Predicting total urinary nitrogen excretion from urinary urea nitrogen excretion in multiple-trauma patients receiving specialized nutritional support

OBJECTIVE: We investigated the accuracy of methods to estimate total urinary nitrogen (TUN) excretion from urinary urea nitrogen (UUN) excretion for patients who have multiple trauma and receive specialized nutritional support. METHODS: Fifty-five critically ill, adult patients who had multiple trauma and were receiving specialized nutritional support were evaluated. A 24-h urine collection for urea nitrogen and total nitrogen was performed 4.4 +/- 2.6 d after admission to the trauma intensive care unit. Patients with significant renal impairment, liver dysfunction, or obesity (>150% of ideal body weight) were excluded from study entry. Eight publications that examined the relation between TUN and UUN were evaluated for bias and precision in estimating TUN from UUN. RESULTS: TUN was 20.8 +/- 10.8 g/d with an average difference of 3.8 +/- 2.8 g/d between TUN and UUN. Linear regression analysis comparing TUN with UUN indicated a significant correlative relation (TUN = 1.1 x UUN + 2; r = 0.958, P < 0.001). The difference between TUN and UUN varied based on UUN: for UUN lower than 10 g/d, TUN minus UUN was 1.5 +/- 1.0 g/d; for UUN 10 to 20 g/d, TUN minus UUN was 4.1 +/- 3.2 g/d; and for UUN higher than 20 g/d, TUN minus UUN was 5.3 +/- 1.9 g/d (P < 0.001). Six methods were biased toward underpredicting TUN, one method was unbiased, and one was biased toward overpredicting TUN. A practical method for estimating TUN from UUN was developed: TUN = UUN + 2 for those with UUN lower than 10 g/d and TUN = 1.1 x UUN + 2 for those with UUN of at least 10 g/d. CONCLUSIONS: Our method, the modified Velasco method, UUN/0.84, and UUN/0.85 provided reasonable estimates of TUN from UUN in critically ill, adult patients who had multiple trauma and were receiving specialized nutritional support; however, our method requires further validation.     

Influence of branched-chain amino acid supplementation on urinary protein metabolite concentrations after swimming

OBJECTIVE: The influence of branched-chain amino acid (BCAA) supplementation on urinary urea nitrogen, hydroxyproline (HP), and 3-methylhistidine (3MH) concentrations after 25 min of breast stroke exercise (65-70% maximum heart rate reserved, 65-70% HRRmax) followed by a 600 m crawl stroke competition was investigated in a double-blind, counter-balanced study. METHODS: Male university students (19-22 years old) majoring in physical education participated in the study. Based on the previous swimming time of a 600 m crawl stroke, the participants were divided into two groups: placebo (n = 9, BMI = 24.2 +/- 2.1 kg/m2; 12 g of glucose/day; in capsules) and BCAA (n = 10, BMI = 22.7 +/- 1.5 kg/m2; 12 g of BCAAs/day; in capsules: leucine 54%, isoleucine 19%, valine 27%) groups. The participants maintained a regular dietary intake (except the prescribed breakfast on day 15) and exercise activity at a moderate/low intensity (60-70% HRRmax, swimming and rowing, approximately 1.5 hour/day) during the 15-day study. A prescribed exercise program was performed on day 15. Urinary and blood samples were collected before, during, and after the prescribed exercise for the measurements of the urinary urea nitrogen, HP, and 3MH concentrations in urine, as well as the glucose, lactate, glutamine, alanine, and BCAA concentrations in plasma. RESULTS: Two weeks of dietary supplementation did not induce any changes in the plasma glucose and total BCAA concentrations of either group, nor in the urinary urea nitrogen, HP, and 3MH concentrations in urine. On day 15, after 25 min of breast stroke exercise and a 600 m crawl stroke competition, plasma glucose concentration decreased significantly (p < 0.05) whereas plasma lactate concentration increased significantly (p < 0.05) in both groups. The exercise program prescribed in the study did not affect urinary urea nitrogen, HP, and 3MH concentrations. Twenty hours after the competition, however, a significant increase in the concentrations of urinary urea nitrogen, HP, and 3MH was found in the placebo group (p < 0.05), but not in the BCAA group. CONCLUSIONS: The results obtained in this study suggest that swimming induced muscle proteolysis was prevented by BCAA supplementation. The mechanism could be attributed to the availability of ammonia provided by the oxidation of supplemented BCAAs during exercise.     

Amino acid metabolism during total parenteral nutrition in healthy volunteers: evaluation of a new amino acid solution

The aim of this study was to determine the metabolism and the tolerance of a new amino acid (AA) solution administered under conditions mimicking cyclical parenteral nutrition (PN) in humans. Eight healthy volunteers received peripheral PN for 10 h providing 10.5 mg N x kg(-1) x h(-1) and 2.0 kcal x kg(-1) x h(-1) (glucose-to-lipids ratio: 70/30%). For adaptation, a non-protein energy intake was increased progressively for 90 min; thereafter, AA infusion was started and maintained at a constant rate for 10 h. Plasma and urine concentrations of all the AAs were measured before, during and after the PN. For each given AA, the relation between plasma variations at the steady-state and infusion rate, plasma clearance (Cl), renal clearance (Clr), re-absorption rate (Reab) and, retention rate (Reten) were determined. The nitrogen balance (DeltaN) was calculated during the PN period. The results are presented as means+/-sem. All plasma AA concentrations decreased during the starting period of non-protein energy intake. The plasma AA concentrations reached a steady-state within 3 h upon AA infusion, except for glycine and lysine (6 h). At the steady state, the plasma concentrations of the infused AAs were closely correlated to their infusion rate (y= -18.3+1.5x, r(2)=0.92). The plasma glutamine concentration was maintained during the PN, which indicates that the solution might stimulate the de novo synthesis of this AA. When the PN was stopped, plasma levels of the AAs decreased, most of them returning to their basal levels, or significantly below for lysine (P<0.05), alanine (P<0.05), proline (P<0.01) and glutamine (P<0.05). No volunteer showed any adverse effect during the infusion period. DeltaN was: 0.8+/-0.5 gN/10 h. Metabolic characteristics for essential AAs were: Cl<0.5 l min(-1), Clr <1.5 ml x min(-1) Reab >or= 99%, Reten >or=99% and for non-essential AAs: Cl <0.6 l x min(-1) except aspartate (2.8+/-0.3 l x min(-1)), Clr < 3 ml x min(-1) except glycine (6.8+/-0.7), aspartate (8.2+/-3.5) and histidine (8.8+/-1.3); Reab >or= 98% except glycine (95+/-1), aspartate (94+/-2) and histidine (94+/-1), Reten >or=97% except histidine (94+/-1), glycine (95+/-3). These results indicate that in healthy subjects, the amounts of AAs provided by the new solution were well balanced for an intravenous administration, and so were well utilized without excessive urinary excretion. The present study provides useful metabolic parameters for a further evaluation in disease.     

Proposal of a new formula to calculate total urinary nitrogen from urea urinary nitrogen

Urea urinary nitrogen (UUN) and total urinary nitrogen (TUN) were determined in 15 patients to study their relationship mainly in highly catabolic patients. The subjects were: 7 multiple trauma, 3 autologous bone-marrow transplant, 1 tetanus, 4 postcholecystectomy patients; 180 determination were made, 111 of which in highly catabolic phase (TUN > 15 g/day). TUN and UUN are well correlated (r = 0.9742; p < 0.001) in the range 3 to 52 g/ day of TUN. Urea represents the 83.2 +/- 9.4% (M +/- SD). A double-linear formula to calculate TUN from UUN is proposed (for UUN 15 g/ day: TUN = UUN x 1.17 + 0.7; for UUN > 15 g/ day: TUN = UUN + 4). The least square procedure was used to compare the differences between measured and calculated TUN, and the results obtained with the proposed double-linear formula were compared with that obtained employing pre-existing formulas (Lee's and Mackenzie's). Considering all ranges of values studied (3-52 g of TUN) the results obtained were significantly different (p < 0.005); dividing the levels of TUN in 15 g; 16-29 g and 30 g, the results were always better, but the statistical significancy was not always reached.     

Continuous versus cyclic parenteral nutrition during bone marrow transplantation: assessment and follow-up

The aim of this prospective, randomized clinical trial was to compare the efficacy of parenteral nutrition (PN) in adult bone marrow transplant (BMT) patients on a continuous (CON) versus a cyclic (CYC) regimen. Twelve patients received CON PN and 12 CYC PN. The groups were homogeneous. CON PN received 27.2 +/- 3.7 kcal/kg/day and for CYC PN 25.9 +/- 4.2 kcal/kg/day (P= 0.45). The duration of PN was 20.4 +/- 7.9 days and 27.3 +/- 13.4 days respectively (P = 0.14). There were no differences between initial and final body weights, either within or between groups. The initial pre-albumin levels were 16.1 +/- 7.5 mg/dl and 20.1 +/- 4.9 mg/dl in CON PN and CYC PN, respectively (P= 0.22), and these were maintained throughout the study. Blood glucose levels did not differ between groups. Measures of liver function were moderately increased, but with no significant differences between groups. There were no significant differences regarding the efficacy of PN or the appearance of complications between CON PN and CYC PN in patients with BMT.     

Influence of calorie source on the physiological response to parenteral nutrition in malnourished rabbits

The present study was designed to investigate whether calorie source influences sodium and water metabolism and sympathetic activity during parenteral nutrition (PN). 20 New Zealand rabbits were starved until a mean weight loss of 18% was achieved and then re-fed for 6 days with 2 formulae of PN with different glucose-fat proportions. In the Glucose group (n = 9), 70% of non-protein calories were given as glucose while in the Lipid group (n = 11), 70% of non-protein calories were administered as lipids. Rabbits with a high glucose intake showed significantly higher weight gain (151 +/- 87 vs. 52 +/- 7 g, P = 0.01), water cumulative balance (542 +/- 132 vs. 411 +/- 87 ml; P = 0.02) and urinary metanephrine excretion (0.42 +/- 0.12 vs. 0.30 +/- 0.1 mumol/d, P = .03). Only in this group, urinary metanephrines correlated positively with water and sodium balances (r2 = 0.6; P = 0.02 and r2 = 0.7; P = 0.009 respectively). The Glucose group showed 2 different responses and in a second experiment 10 additional rabbits were added to this group to allow a statistical analysis of the response pattern: half of the animals increased their extracellular water (ECW) compartment while the remaining animals did not. The former group had higher sodium balance (13.9 +/- 8 vs. 4.3 +/- 5; P = 0.004) and wet lung weight (8.9 +/- 0.9 vs. 7.9 +/- 0.8; P < 0.05) after re-feeding and, at the beginning of PN, their serum aldosterone concentration were also higher (221 +/- 11 vs. 130 +/- 47 pmol/l; P < 0.05). In conclusion, glucose based PN appears to increase sympathetic activity and induce spurious weight gain due to markedly positive wate and sodium balances. Plasma aldosterone concentration at the end of starvation period influences sodium retention and ECW expansion during high glucose re-feeding.     

Body burdens of lead in hypertensive nephropathy

Chronic lead exposure resulting in blood lead concentrations that exceed 1.93 mumol/l (40 micrograms/dl) or chelatable urinary lead excretion greater than 3.14 mumol (650 micrograms) per 72 h has been associated with renal disease. A previous study had found greater chelatable urine lead excretion in subjects with hypertension and renal failure than in controls with renal failure due to other causes, although mean blood lead concentrations averaged 0.92 mumol/l (19 micrograms/dl). To determine if chelatable urinary lead, blood lead, or the hematologic effect of lead (zinc protoporphyrin) were greater in hypertensive nephropathy (when hypertension precedes elevation of serum creatinine) than in other forms of mild renal failure, we compared 40 study subjects with hypertensive nephropathy to 24 controls having a similar degree of renal dysfunction due to causes other than hypertension. Lead burdens were similar in both the study and control groups as assessed by 72-h chelatable urinary lead excretion after intramuscular injection of calcium disodium EDTA (0.74 +/- 0.63 vs. 0.61 +/- 0.40 mumol per 72 h, respectively), and by blood lead (0.35 +/- 0.23 vs. 0.35 +/- 0.20 mumol/l). We conclude that subjects from a general population with hypertensive nephropathy do not have greater body burdens of lead than renal failure controls.     

A simple method for estimating nitrogen balance in hospitalized patients: a review and supporting data for a previously proposed technique

Total urinary nitrogen (TUN) and urinary urea nitrogen (UUN) in a 24-hour urine collection were measured under a variety of clinical and nutritional conditions in 81 patients for 564 study days. The difference between TUN and UUN averaged 1.8 +/- 0.9 g/day (range 0.0-5.8 g/day) and was independent of the absolute value for UUN. Since UUN was found to correlate linearly with TUN (R = 0.98) over a wide range of values, it is possible to estimate an approximate TUN excretion by adding a constant to the nitrogen excreted as urea. On the basis of the measured mean difference, we suggest using an estimate of 2 g of nitrogen per day. We feel this will not seriously under- or overestimate urinary nitrogen excretion in the calculation of nitrogen balance for the clinical management of nutritional support therapies. Since all hospitals can perform this routine test, it provides an effective, simple, and rapid method to follow accurately the protein catabolic response during disease and response to nutritional therapy. This method, without the supporting data presented here, has previously been recommended [Blackburn et al, 1977, JPEN 1:11-22] and has become a widely used technique for nutritional assessment.     

Hepatic de novo lipogenesis in stable low-birth-weight infants during exclusive breast milk feedings and during parenteral nutrition

BACKGROUND: Low-birth-weight (LBW) infants have high energy requirements and are dependent on high fat intake to maintain adequate postnatal growth. Fat energy is transported in plasma as triglycerides, which are either derived from the diet or from de novo lipogenesis (DNL). It is our hypothesis that DNL plays an important physiologic role in adapting to exclusive breast milk (EBM) feeding or to parenteral nutrition (PN). METHODS: We studied hepatic de novo lipogenesis in 14 LBW (<34-week gestation) appropriate for gestational age and receiving either EBM feedings or full PN support. Stable isotope tracer [2-(13)C] acetate was administered for 72 hours to achieve an estimated 10% enrichment of daily fat intake. Fatty acids were extracted from plasma for gas chromatography-mass spectrometry analyses. RESULTS: Percent new synthesis of palmitate was 13.1% +/- 2.5% in the EBM group and 14.9% +/- 0.7% in the PN group (NS), stearate was 11.1% +/- 2.7% in the EBM group and 10.6% +/- 14% in the PN group (NS) and cholesterol was 12.7% +/- 2.1% in the EBM group and 17.4% +/- 4.6% in the PN group (NS) after 72 hours of tracer administration (mean +/- SEM). The plasma lipid fatty acid composition in palmitate, oleate, and stearate with intake of 3.6 +/- 0.6 g/kg/d of IV lipids (ILs) was similar to EBM-feeding infants taking 6.3 +/- 0.13 g/kg/d of fat. CONCLUSIONS: De novo lipogenesis is active in stable LBW infants maintaining standard postnatal growth. Hepatic DNL permits newborn infants to meet the fat energy needs of peripheral tissues for growth and storage and to maintain plasma fatty acid composition in adaptation to different dietary fat intake.     

Status of lipidsoluble antioxidants and TRAP in patients with Crohn's disease and healthy controls.

OBJECTIVE: To assess the status of lipidsoluble antioxidants (carotenoids, tocopherols, ubiquinone), retinol and their correlation with TRAP (total radical-trapping antioxidant potential) in patients with Crohn's disease. DESIGN: Prospective case-control study. SETTING: Clinic of Internal Medicine IV/Department of Gastroenterology and Hepatology, University of Vienna Medical School. SUBJECTS/METHODS: Plasma antioxidant concentrations were determined in patients with Crohn's disease (n = 24) to evaluate the antioxidant capacity compared to healthy controls (n = 33). Additionally, plasma TRAP (total radical-trapping antioxidant potential) was measured in 13 patients and 22 controls. RESULTS: All investigated carotenoids (alpha-carotene, beta-carotene and cryptoxanthin) were significantly decreased in patients with Crohn's disease (10.2 +/- 9.3, 16.2 +/- 12.4 and 7.8 +/- 5.5 microg/dl) compared to controls (13.3 +/- 5.1, 34.7 +/- 18.8 and 48.5 +/- 38.4 microg/dl respectively), whereas gamma-tocopherol and ubiquinone were significantly elevated in patients (0.14 +/- 0.07 microg/dl and 82.3 +/- 41.5 microg/dl, controls: 0.09 +/- 0.04 microg/dl and 60.8 +/- 30.0 microg/dl, respectively). Retinol and alpha-tocopherol did not significantly differ from controls. The total radical-trapping antioxidant potential (TRAP) was significantly lower in patients (1.11 +/- 0.28 micromol/l) compared to controls (1.34 +/- 0.26 micromol/l). Antioxidants were neither related to duration or severity of disease nor to disease activity. CONCLUSIONS: In patients with Crohn's disease several plasma antioxidant parameters are altered and the total radical-trapping antioxidant potential is decreased.     

Influence of Branched-Chain Amino Acid Supplementation on Urinary Protein Metabolite Concentrations after Swimming

Objective: The influence of branched-chain amino acid (BCAA) supplementation on urinary urea nitrogen, hydroxyproline (HP), and 3-methylhistidine (3MH) concentrations after 25 min of breast stroke exercise (65–70% maximum heart rate reserved, 65–70% HRRmax) followed by a 600 m crawl stroke competition was investigated in a double-blind, counter-balanced study.

Methods: Male university students (19–22 years old) majoring in physical education participated in the study. Based on the previous swimming time of a 600 m crawl stroke, the participants were divided into two groups: placebo (n = 9, BMI = 24.2 ± 2.1 kg/m²; 12 g of glucose/day; in capsules) and BCAA (n = 10, BMI = 22.7 ± 1.5 kg/m²; 12 g of BCAAs/day; in capsules: leucine 54%, isoleucine 19%, valine 27%) groups. The participants maintained a regular dietary intake (except the prescribed breakfast on day 15) and exercise activity at a moderate/low intensity (60–70% HRRmax, swimming and rowing, ～1.5 hour/day) during the 15-day study. A prescribed exercise program was performed on day 15. Urinary and blood samples were collected before, during, and after the prescribed exercise for the measurements of the urinary urea nitrogen, HP, and 3MH concentrations in urine, as well as the glucose, lactate, glutamine, alanine, and BCAA concentrations in plasma.

Results: Two weeks of dietary supplementation did not induce any changes in the plasma glucose and total BCAA concentrations of either group, nor in the urinary urea nitrogen, HP, and 3MH concentrations in urine. On day 15, after 25 min of breast stroke exercise and a 600 m crawl stroke competition, plasma glucose concentration decreased significantly (p < 0.05) whereas plasma lactate concentration increased significantly (p < 0.05) in both groups. The exercise program prescribed in the study did not affect urinary urea nitrogen, HP, and 3MH concentrations. Twenty hours after the competition, however, a significant increase in the concentrations of urinary urea nitrogen, HP, and 3MH was found in the placebo group (p < 0.05), but not in the BCAA group.

Conclusions: The results obtained in this study suggest that swimming induced muscle proteolysis was prevented by BCAA supplementation. The mechanism could be attributed to the availability of ammonia provided by the oxidation of supplemented BCAAs during exercise.     

Blood lead levels and bone turnover with weight reduction in women

High bone turnover states are known to raise blood lead levels (BPb). Caloric restriction will increase bone turnover, yet it remains unknown if weight reduction increases BPb due to mobilization of skeletal stores. We measured whole blood Pb levels ((206)Pb) by inductively coupled plasma mass spectrometry in 73 women (age 24-75 years; BMI 23- 61 kg/m(2)) before and after 6 months of severe weight loss (S-WL), moderate weight loss (M-WL), or weight maintenance (WM). Baseline BPb levels were relatively low at 0.2-6.0 microg/dl, and directly associated with age (r=0.49, P<0.0001). After severe WL (-37.4+/-9.3 kg, n=17), BPb increased by 2.1+/-3.9 microg/dl (P<0.05), resulting in BPb levels of 1.3-12.5 microg/dl. M-WL (-5.6+/-2.7 kg, n=39) and WM (0.3+/-1.3 kg, n=17) did not result in an increase in BPb levels (0.5+/-3.2 and 0.0+/-0.7 microg/dl, M-WL and WM, respectively). BPb levels increased more with greater WL (r=0.24, P<0.05). Bone turnover markers increased only with severe WL and were directly correlated with WL. At baseline, higher calcium intake was associated with lower BPb (r=-0.273, P<0.02), however, this association was no longer present after 6 months. Severe weight reduction in obese women increases skeletal bone mobilization and BPb, but values remain well below levels defined as Pb overexposure.     

肝硬化大鼠肝部分切除术后肠外营养时氨基酸溶液的选择及评估

目的探讨肝硬化大鼠肝部分切除术后肠外营养时氨基酸溶液的选择及评估。方法6只正常大鼠作为正常对照组熏24只肝硬化大鼠随机分为肝硬化术前组、肝硬化肝部分切除术后1天组、肝部分切除术后行复方18种氨基酸溶液的肠外营养5天组、肝部分切除术后行富含支链氨基酸穴BCAA雪的氨基酸溶液的肠外营养5天组,每组6只。检测大鼠肝功能、血糖及血清生长激素穴GH雪、胰岛素样生长因子-1穴IGF-1雪、胰岛素样生长因子结合蛋白-3穴IGFBP-3雪,肝组织行Ki67免疫组化染色,结果判断计数采用Ki67指数。结果与复方18种氨基酸溶液的肠外营养比较,富含BCAA的氨基酸溶液的肠外营养5天后血清谷丙转氨酶穴ALT雪、碱性磷酸酶穴ALP雪水平降低熏GH水平也降低熏而IGF-1、IGFBP-3水平升高穴P<0.05雪熏但肝Ki67指数无显著性差异穴P>0.05雪。血清GH水平与谷草转氨酶穴AST雪、ALT、ALP呈正相关熏与白蛋白穴ALB雪呈负相关穴P<0.05雪熏而血清IGF-1、IGFBP-3水平与AST、ALT、ALP呈负相关熏与ALB呈正相关穴P<0.05雪。结论肝硬化肝部分切除术后肠外营养应选择富含BCAA的氨基酸溶液,检测血清GH、IGF-1、IGFBP-3有助于对营养素选择的评估。     

Effect of administered human growth hormone on protein metabolism in septic rats

The effect of administered human growth hormone (hGH) on protein metabolism in septic rats was investigated. Fifty-three male Wistar rates with SVC cannulation were divided into four groups. Group I (n = 10) underwent sham-operation. Sepsis was induced by cecal ligation in group II (n = 19), group III (n = 10), and group IV (n = 14). Isocaloric, isonitrogenous glucose/amino acids were infused for 4 days. hGH was administered in group III (100 mU/day) and group IV (200 mU/day) every day. Cumulative nitrogen balance (mg/kg) in group IV was significantly higher than in group II (p less than 0.01): group I, 1264 +/- 355; group II, 117 +/- 693; group III, 92 +/- 735; group IV, 1001 +/- 279. Cumulative urinary excretion of 3-methylhistidine (3-MH, mg/kg) did not differ between group II and group IV: group I, 6.2 +/- 0.9; group II, 12.0 +/- 2.2; group III, 13.4 +/- 2.9; group IV, 10.5 +/- 2.3. Serum albumin level in group IV (1.8 +/- 0.2 g/dl) was significantly higher than in group II (1.5 +/- 0.2 g/dl) (p less than 0.01). Blood urea nitrogen level in group IV (12.6 +/- 2.3 mg/dl) was significantly lower than in group II (18.8 +/- 7.4 mg/dl) (p less than 0.05). Although serum levels of glucose, insulin, triglyceride, and phospholipid were higher in sepsis groups than in sham-operated group, those levels did not differ among sepsis groups. Administration of hGH, 200 mU/day, resulted in marked nitrogen retention and had little effect on 3-MH excretion.(ABSTRACT TRUNCATED AT 250 WORDS)     

Vitamin D requirement in infants receiving parenteral nutrition

The adequacy of low dose vitamin D (25 IU/dl) parenteral nutrition (PN) solution was studied in 18 infants. All infants had surgical indications for PN. The birth weights were 2810 +/- 135 g and gestational ages 37.4 +/- 0.5 wk (mean +/- SEM). Duration of study ranged from 5 to 175 days. Thirteen infants were studied for up to 6 weeks and five infants for 71 to 175 days. Results showed that studied infants maintained growth along normal percentiles for weight, length, and head circumference. Vitamin D status as indicated by serum 25 hydroxyvitamin D (25 OHD) rose from 15 +/- 1.9 ng/ml to 26 +/- 2.8 ng/ml, mean +/- SEM (p less than 0.001) after 9 days, and remained normal up to 6 months. Five infants with biochemical liver dysfunction also had normal serum 25 OHD concentrations, indicating the hepatic 25 hydroxylation process was not severely impaired. Serum total and ionized calcium, phosphorus, and vitamin D-binding protein concentrations were normal. Serum magnesium was mildly elevated in five infants (2.6 to 3 mg/dl) on one occasion and resolved spontaneously. Serum alkaline phosphatase (AP) concentrations rose above baseline values in 12 of 17 infants, but remained within normal range (less than 400 IU/liter at 30 degrees C). Another infant with markedly elevated AP values died from liver dysfunction. Radiographs of the forearms were normal except for marked demineralization in one infant in spite of normal 25 OHD concentrations. We conclude that 25 IU vitamin D/dl of nutrient infusate is adequate to maintain normal vitamin D status, as indicated by normal serum 25 OHD concentrations in infants receiving PN for as long as 6 months.     

Endotoxin-mediated hepatic lipid accumulation during parenteral nutrition in rats

OBJECTIVE: To assess the effect of endotoxemia on hepatic lipid content during parenteral nutrition (PN) in rats. METHODS: Twenty male Sprague-Dawley rats (185-230 gm) were randomized to receive PN (n=9) or PN plus a continuous infusion of E. coli 026:B6 lipopolysaccharide (LPS; n= 11). All animals received isocaloric (170 kcal/kg/day), isonitrogenous (1.1 g N/kg/day), glucose-based PN for the next 78 hours. After 30 hours of adaptation to TPN, the animals were randomized to receive PN or PN plus LPS at 6 mg/kg/day for the remaining 48 hours of study. The animals were euthanized and the livers were harvested. RESULTS: Liver weight increased significantly (by 60%) from 7.5+/-0.6 g to 12.1+/-2.4 g (p < or = 0.01) in the animals who received PN versus LPS, respectively. The proportion of liver water remained the same for PN and LPS groups (72.9+/-3.2% versus 72.3+/-3.8%, respectively, p = N.S.). However, liver fat increased disproportionately (by about 130%) from 0.20+/-0.05 g to 0.46+/-0.20 g (p < or = 0.01) total fat weight or from 9.6+/-1.8% to 13.6+/-4.1% (p < or = 0.02) lipid content (g/g) of the dry liver weight for the PN and LPS groups, respectively. CONCLUSION: Endotoxin, when given concomitantly with parenteral nutrition, increases hepatic lipid accumulation and thus augments the development of parenteral nutrition-associated fatty liver in rats.     

Use of parenteral nutrition in patients receiving isolated kidney or simultaneous pancreas/kidney transplantation

BACKGROUND: There is little information available on the use of parenteral nutrition (PN) in patients after a kidney (KID) or simultaneous pancreas-kidney (SPK) transplantation. This study examined the indications and use of PN in these patients. METHODS: Retrospective study of 25 patients (12M/13F; mean age: 51 +/- 11 years old) receiving PN after KID or SPK transplantation. Patients were divided in 2 groups according to the number of PN days (group A = <7 days and group B = >7 days). RESULTS: Overall mortality was 16% (group A: 0/7; group B: 4/18). Postoperative ileus (n = 7), intestinal fistula (n = 5), and nausea/vomiting (n = 4) were the most common indications for PN. Functional disorders accounted for 56% (14/25) of the indications for PN. Factors differentiating group A (7/25; median = 5 [4-6] days) from group B (18/25; median =9 [7-31] days) included a significantly higher preoperative serum albumin, SPK transplantation for the first time, and diagnosis of ileus as the indication for PN initiation. CONCLUSIONS: Functional disorders of the digestive tract are the primary reason for initiation of PN in isolated KID and SPK transplantation patients. Well-nourished patients undergoing their first SPK transplantation who develop postoperative ileus usually do not need nutrition intervention.     

The impact of parenteral nutrition on the body composition of patients with acute pancreatitis

BACKGROUND: Nutrition support by the enteral route is now the preferred modality in patients with severe acute pancreatitis. Parenteral nutrition is now required to supplement enteral nutrition when the latter is not able to provide the full nutritional requirement. We report the changes in body composition, plasma proteins, and resting energy expenditure (REE) during 14 days of parenteral nutrition (PN) in patients with acute pancreatitis. METHODS: Total body protein (TBP), total body water (TBW), and total body fat (TBF) were measured by neutron activation analysis and tritium dilution before and after PN. Fat-free mass (FFM) was derived as the difference between body weight and TBF. REE was measured by indirect calorimetry. Protein index (PI) was the ratio of measured TBP to TBP, calculated from healthy volunteers. RESULTS: Fifteen patients with acute pancreatitis (11 men, 4 women; median age 56, range 30-80 years) were studied. Thirteen patients had severe acute pancreatitis (Atlanta criteria), and 1 patient died. The gains in body weight (1.05 +/- 0.77 kg), TBW (0.49 +/- 0.87 kg), TBP (0.20 +/- 0.22 kg), FFM (0.73 +/- 0.92 kg), TBF (0.32 +/- 0.95 kg), and REE (146 +/- 90 kcal/d) after 14 days of PN were not significant. Plasma prealbumin increased by 46.5% (p = .020). When patients (n = 6) with intercurrent sepsis and recent surgery were excluded, there were significant increases in TBP (0.65 +/- 0.17 kg, p = .005) and PI (0.060 +/- 0.011, p = .0006). CONCLUSIONS: Body composition is preserved in acute pancreatitis during 14 days of PN. In patients without sepsis or recent surgery, PN is able to significantly increase body protein stores.     

Plasma lipid concentrations in college students performing self-selected exercise

Plasma cholesterol and other blood lipids were determined in 64 college juniors and seniors during January and February 1989 (before exercise) and again during April and May 1989 (after exercise). A 14-week period of self-selected exercise was interposed between the before and after exercise cholesterol determinations. Cholesterol concentrations ranged from 127-273 mg/dl (before exercise) to 131-261 mg/dl (after exercise) in this group of students who were 22 +/- 1 years of age. There were no statistically significant differences in cholesterol concentrations between the genders. Students could be further subdivided into groups with low (144 +/- 3 mg/dl, n = 12), medium (176 +/- 6 mg/dl, n = 35), and high (224 +/- 6 mg/dl, n = 17) concentrations of cholesterol. Only students in the high cholesterol group experienced a significant reduction in total cholesterol and low-density-lipoprotein cholesterol after 14 weeks of exercise. High-density-lipoprotein cholesterol concentrations were significantly higher in women than in men in both the medium and high cholesterol subgroups before and after exercise. From these results it appears that a significant fraction of the young adult college population could be at increased risk of coronary heart disease because of inappropriately high concentrations of cholesterol. Moreover, self-selected exercise, if engaged in regularly, can reduce blood cholesterol significantly in students with high cholesterol concentrations.     

Esophageal zinc content in human squamous esophageal cancer

Zinc and vitamin A are known to interact, and deficiencies have been associated with carcinogenesis in experimental animals and humans. Since we previously have demonstrated decreased plasma zinc and vitamin A levels in patients with esophageal cancer, we wished to examine endoscopically obtained epithelial tissue for vitamin A and zinc content. This was not feasible for vitamin A, but using newly developed techniques for zinc analysis of small tissue samples, we measured esophageal epithelial zinc as well as plasma zinc and plasma vitamin A in 21 patients with esophageal cancer, 17 patients with esophagitis, and 12 normals. Mean plasma zinc in the esophageal cancer group (56 +/- 3 micrograms/dl) (mean +/- SEM) was significantly less than in the esophagitis group (72 +/- 5 micrograms/dl) and the normals (78 +/- 5 micrograms/dl). Mean plasma vitamin A in the esophageal cancer group (32 +/- 3 micrograms/dl) was significantly less than the esophagitis group (57 +/- 4 micrograms/dl) or the normals (58 +/- 5 micrograms/dl). There was no significant difference in tissue zinc content (measured as micrograms zinc/g wet weight of tissue, mean +/- SEM) among cancerous tissue (57 +/- 5 micrograms/g) and adjacent normal tissue (61 +/- 4 micrograms/g), esophagitis tissue (66 +/- 6 micrograms/g) and adjacent normal tissue (61 +/- 6 micrograms/g), or normal esophageal tissue (59 +/- 6 micrograms/g). We conclude that deficiencies of zinc or vitamin A may be cofactors in the induction of human esophageal cancer, but a mechanism cannot be accounted for by differences in epithelial zinc content.