Improved albumin synthesis in postoperative patients by amino acid infusion

Effects of amino acids and albumin administration on albumin metabolism in surgically stressed rats: A basic nutritional study

BACKGROUND

Nutrition therapy and administration of albumin preparations are common in postsurgical patients. However, the effects of these interventions on albumin metabolism are unclear. We elucidated the effect of postoperative albumin and/or parenteral nutrition administration on it.

METHODS

Sprague-Dawley rats underwent surgery involving intestinal rubbing followed by intestinal exposure. Subsequently, they were administered experimental solutions for 48 h, their blood samples were collected at 24 and 48 h, and livers were excised at 48 h. Based on experimental solutions, rats were divided into five groups: non-surgical (Non-surg); glucose and electrolyte solution (GE); amino acid, glucose, and electrolyte solution (AGE); GE + rat serum albumin (Alb) (GE + Alb); and AGE + Alb. Their plasma albumin concentrations; albumin fractional synthesis rate (ALB FSR); mercaptoalbumin/total albumin ratio (MA ratio); and messenger RNA (mRNA) expressions of albumin and hepatocyte nuclear factor-1 (HNF-1) in the liver were measured.

RESULTS

The GE and AGE groups showed significant decline in albumin concentrations. ALB FSR was significantly enhanced in the AGE group compared with the GE group. The mRNA expression of albumin was similar to ALB FSR in all groups and that of HNF-1 was significantly decreased in the GE + Alb and AGE + Alb groups compared with the Non-surg group. The MA ratio in the AGE group was similar to the Non-surg group.

CONCLUSION

The administration of amino acids comprising parenteral nutrition after surgery augmented ALB FSR and maintained the MA ratio only without simultaneous albumin administration.

Protein Loss after Radical Mastectomy as a Cause of Postoperative Hypoalbuminemia

The concentrations of serum albumin and the cumulative loss of albumin through the drainage tubes were followed in 14 patients who underwent radical mastectomy for cancer. The concentration of serum albumin declined during the postoperative period, and the nadir was on the 5th day. On the first 5 days a good correlation was observed between hypoalbuminemia and loss of albumin from the wound. After this period, hypoalbuminemia persisted unchanged although small quantities of albumin continued to be lost through the drains. It is concluded that in surgery complicated by abundant serum discharge, the albumin loss may be the main cause of postoperative hypoalbuminemia.

Effect of Supportive Intravenous Hyperalimentation on the Nutritional Status of Cancer Patients

The effect of intravenous hyperalimentation on the nutritional status of 84 cancer patients treated at the Istituto Nazionale Tumori, Milan, has been evaluated. The body weight increased in 78 % of patients, mid upper arm circumference in 93 %, triceps skinfold in 73 %, mid upper arm-muscle circumference in 73 %, creatinine/height index in 30 %, serum albumin in 32 %, transferrin in 35 %, total peripheral lymphocytes in 38 %. Lymphocyte blastogenesis increased in 74 % of the patients examined and skin tests were converted from negative to positive in about 20 % of patients. In addition 8 out of 18 patients responsive to IVH benefited from chemotherapy and/or radiotherapy indicating that the nutritional repletion of the host did not significantly affect the growth of the tumor. These findings support the opinion that neoplastic cachexia may depend partially on malnutrition and can be often reversed by IVH. Moreover, IVH might have an adjunctive role as potentiator of chemotherapy which however must be confirmed by clinical trials.

Protein sparing therapies in acute illness and obesity: a review of George Blackburn's contributions to nutrition science

Protein sparing therapies were developed to mitigate the harms associated with protein-calorie malnutrition and nitrogen losses induced by either acute illness or hypocaloric diets in patients with obesity. We review the development of protein sparing therapies in illness and obesity with a focus on the pioneering contributions of George Blackburn, MD, PhD. He recognized that protein-calorie malnutrition is a common and serious clinical condition and developed new approaches to its treatment in hospitalized patients. His work with stable isotopes and with animal models provided answers about the physiological nutritional requirements and metabolic changes across a spectrum of conditions with varying degrees of stress and catabolism. This led to improvements in enteral and parenteral nutrition for patients with acute illness. Blackburn also demonstrated that lean body mass can be preserved during weight loss with carefully designed very low calorie treatments which became known as the protein sparing modified fast (PSMF). We review the role of the PSMF as part of the comprehensive management of obesity.

Albumin and whole-body protein synthesis respond differently to intraperitoneal and oral amino acids

Patients with peritoneal dialysis are at risk for malnutrition and hypoalbuminemia, which are indicators of poor outcome. Recently, it was shown that dialysis solutions containing amino acids (AAs) and glucose improve protein anabolism in peritoneal dialysis patients. We determined if the same solutions could increase the fractional synthesis rate of albumin along with whole-body protein synthesis. Changes in the fractional albumin synthetic rate reflect acute change in hepatic albumin synthesis. A random-order cross-over study compared the effects of Nutrineal (AA source) plus Physioneal (glucose) dialysate with Physioneal alone dialysate. Eight patients in the overnight fasting state were compared to 12 patients in the daytime-fed state. Fractional albumin synthetic rate and whole-body protein synthesis were determined simultaneously using a primed-continuous infusion of L-[1-(13)C]-leucine. Fractional albumin synthesis on AAs plus glucose dialysis did not differ significantly from that on glucose alone in the fasting or the fed state. Protein intake by itself (fed versus fasting) failed to induce a significant increase in the fractional synthetic rate of albumin. Conversely, the oral protein brought about a significant stimulation of whole-body protein synthesis. Our findings show that the supply of AAs has different effects on whole-body protein synthesis and the fractional synthetic rate of albumin.

Dynamics of albumin synthesis after major rectal operation

BACKGROUND

Major abdominal operations were found to be associated with long-lasting metabolic changes, such as accelerated release of stress hormones and carbohydrate turnover. It is unknown currently whether acute changes of hepatic protein metabolism persist in a similar way. We wanted to determine the long-term dynamics of albumin synthesis and its relationship to whole body protein breakdown and albumin concentration after major rectal operations.

METHODS

We used stable isotope tracer techniques to determine albumin synthesis and whole body protein breakdown (rate of appearance of leucine, Ra) in postoperative patients about 1 week after low anterior rectal resection and also during convalescence (about 4 months after operation), and in healthy controls. Consecutive blood sampling was carried out during continuous isotope infusion (1-[(13)C]-leucine, 0.16 micromol/kg min).

RESULTS

Serum albumin concentrations were close to the lower normal limit in patients early after operation but were comparable to controls in convalescent patients. Simultaneously, albumin synthesis was increased in the early postoperative phase (0.53 +/- 0.0.5%/h) compared with convalescent patients (0.32 +/- 0.04) and controls (0.28 +/- 0.04) (P < .01 each). A significant inverse correlation could be found between plasma albumin concentration and corresponding rates of albumin synthesis. Early after operation patients showed an increased leucine Ra (3.25 +/- 0.23 micromol/kg min) that was greater than that of convalescent patients (2.37 +/- 0.06 micromol/kg min, P < .05). Leucine Ra in both patient groups were greater than the rates in controls (2.01 +/- 0.07 micromol/kg min, P < .01) Albumin synthesis correlated weakly with whole body protein breakdown rate.

CONCLUSIONS

Albumin synthesis and total body protein breakdown are increased after major abdominal operation, but albumin synthesis returns to control values only during convalescence. Hypoalbuminemia after rectal operations may be associated with high rates of albumin synthesis and is, therefore, not necessarily an indicator of insufficient hepatic function or poor nutritional status in that particular situation.

Cysteine and glutathione in catabolic conditions and immunological dysfunction

The conspicuous increase in the plasma cysteine disulphide/thiol ratio in elderly persons and cancer patients indicates a shift of the plasma redox state. The most important redox buffers in skeletal muscle tissue and blood plasma, i.e. glutathione and albumin, respectively, are significantly decreased in different models of cachexia. Treatment with N-acetyl cysteine, i.e. a thiol-containing antioxidant, was found to increase the plasma albumin level and to ameliorate the loss of body cell mass in cancer patients and healthy individuals. The treatment of HIV infection with N-acetyl cysteine, in contrast, serves mainly as a tool to ameliorate the physiological and immunological consequences of the virus-induced cysteine deficiency.

The effects of short-term parenteral nutrition on human liver protein and amino acid metabolism during laparoscopic surgery

BACKGROUND

This study was undertaken to elucidate the specific effects of short-term artificial nutrition on human liver protein metabolism.

METHODS

Thirty patients undergoing elective laparoscopic cholecystectomy were studied: a control group (n = 16) and a group that received total parenteral nutrition (TPN; n = 14). The nutrition consisted of a balanced i.v. solution of nutrients (17.5 nonprotein kcal/kg body wt, 50% fat, 50% carbohydrates, and 0.1 gN/kg) that was discontinued when the investigation was finished, after a total infusion time of 8.6 +/- 1.0 hours. A liver biopsy specimen was taken as soon as possible after surgery was started, for the determination of the free hepatic amino acid concentrations. In 16 of the patients, L[2H5]phenylalanine was given by i.v. to determine the fractional synthesis rate of total liver protein in a second liver biopsy specimen taken approximately 30 minutes later.

RESULTS

The fractional synthesis rate of total liver protein was 15.2% +/- 4.7%/d in the TPN group (n = 7), which was not different from that of the control group (17.7% +/- 3.8%/d, n = 9). However, the free hepatic concentrations of alanine (p < .05) and the essential amino acids increased (p < .001) in the TPN group, whereas the total hepatic amino acid concentrations were comparable between the groups.

CONCLUSION

Thus short-term TPN induced specific changes of the free hepatic amino acid concentrations, whereas total liver protein synthesis remained unaffected by the nutrition.

Effect of essential amino acid supplementation in acute renal failure

The effect of intravenous (i.v.) essential amino acids (EAA) in the treatment of acute renal failure was evaluated in 50 patients. Thirty patients (Group A) received daily 13.4 g of i.v. EAA solution [Nephramine (Don Baxter, McGraw) 250 ml/d]+dopamine i.v. 2 micrograms/kg/min + 20% hypertonic glucose solution 500 ml/d as compared with twenty patients (Group B) who received dopamine i.v. 2 micrograms/kg/min + 20% hypertonic glucose solution 500 ml/d. In Group A patients showed lower daily increase in blood urea nitrogen (BUN) (p < 0.05), higher serum total protein and albumin levels on the 15th day of the posttherapy period (p < 0.001), lower complication rate (p < 0.005), lower mortality rate (p < 0.005) and a reverse relation between serum total protein concentration, duration of oliguria and age (p < 0.01, r2 = 0.26; p < 0.001, r2 = 0.32). These data suggest that treatment of such patients with i.v. EAA solutions significantly improves survival.

[Nutrition proteins and muscular catabolism in severely burnt patients. Comparative effects of small peptides or free amino acids]

The beneficial effects of high caloric and protein enteral diet on wound healing and prevention of infection in severely burned patients is well documented. However, the relative proportion of each nutrient and especially the form of nitrogen supply have not yet been clearly established. The aim of this study was to compare, in severely burned patients, the efficiency of a partial protein hydrolysate and free amino acid formula during a 15-day enteral feeding. Twenty burned patients ranging in age from 18 to 67 years with a mean burn size of 40 +/- 12% of total body surface area, of which 31 +/- 14% was deep dermal, were studied prospectively and randomised in two groups. Group A received the free amino acid diet which was obtained by hydrolysis of the protein hydrolysate given to Group B (60% small peptides). All diets contained a nitrogen source of similar amino acid composition. Nitrogen balance was measured daily and serum protein concentrations were determined on days 0, 4, 8, 11 and 15. Anthropometric parameters, urinary 3 methylhistidine/creatinine ratio and plasma amino acid concentration were assessed on days 0, 8 and 15. Daily and cumulative nitrogen balance at D15 did not differ between the two groups. In group A, the circulating visceral proteins increased at all times of the study without decrease of acute phase reactant, whereas only transthyretin and retinol binding protein increased at D11 and D15 with a significant decrease of C-reactive protein at the same time in the other group.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum visceral protein levels reflect protein-calorie repletion in neonates recovering from major surgery

Protein catabolism resulting from acute metabolic stress causes significant postoperative decreases in visceral proteins, including albumin (Alb) and prealbumin (PA). Although clinical trials have suggested an advantage of PA over Alb in monitoring the visceral protein response to nutritional supplementation following surgery, the capability of the neonate to generate such a response has yet to be evaluated. Therefore, this study was undertaken to determine if PA is superior to Alb in assessing postoperative repletion of the visceral protein pool in neonates. Serum Alb and PA levels were measured and energy balance (EB) and protein intake (PI) were recorded in 10 neonates less than 48 hours after major surgery and again following 4 consecutive days of positive EB. Resting energy expenditure (REE) was measured using indirect calorimetric methodology. Mean PI (g/kg/d) was lower (0.78 +/- 0.78) and mean EB (kcal/kg/d) was negative (-2.92 +/- 10.05) less than 48 hours postoperatively compared with mean PI (2.52 +/- 0.57; P = .0006) after 4 consecutive days of positive EB (34.84 +/- 16.5; P = .0004). Mean percent change (mean% delta) from negative EB to positive EB was significantly greater for PA (100%; P = .0002) as compared with Alb (18.5%). These data appear to support the conclusion that serial serum PA levels are superior to Alb to monitor the visceral protein response to nutritional supplementation in neonates following surgery.

Elevation of albumin synthesis rates in nephrotic patients measured with [1-13C]leucine

Eight patients with a nephrotic syndrome and a histologically-proven kidney disease were compared to age- and sex-matched healthy volunteers. Albumin synthesis rates were measured after injection of 13C-labelled leucine (57 mg/kg body wt, 19.4 atoms%). Plasma volume was determined with 125I-albumin. The fractional synthesis rate of albumin was 7.9 +/- 0.4%/day in control subjects in comparison with a marked elevation to 18.4 +/- 2.0%/day (P less than 0.001) in nephrotic patients. The absolute synthesis rate was 145 +/- 9 mg/kg/day in control subjects compared with 213 +/- 17 mg/kg/day (P = 0.005) in the nephrotic patients. There was a statistically significant correlation between ASR and urinary albumin loss (P = 0.035) and serum cholesterol concentration (P = 0.007). The calculated oncotic pressure was significantly lower in the nephrotic group than in the controls (P less than 0.001), but was without correlation with ASR.

Albumin metabolism in the nephrotic syndrome: the effect of dietary protein intake

The nephrotic syndrome is characterized by increased urinary excretion of albumin and other serum proteins, accompanied by hypoproteinemia and edema formation. Nephrotic patients have lower serum albumin concentrations than do patients undergoing continuous ambulatory peritoneal dialysis when albumin and protein losses are the same in both groups, suggesting that nephrotic patients may not maximally adapt to loss of protein. The fractional rate of albumin catabolism is increased in nephrotic patients, possibly as a result of increased albumin catabolism by the kidney, but the absolute albumin catabolic rate is decreased in nephrotic patients. The rate of albumin synthesis may be increased, but not sufficiently to maintain normal serum albumin concentration or albumin pools. Augmentation of dietary protein in nephrotic rats directly stimulates albumin synthesis by increasing albumin mRNA content in the liver, but also causes an increase in glomerular permeability to macromolecules so that much if not all of the excess albumin synthesized is lost in the urine. When dietary protein is restricted, the rate of albumin synthesis is not increased either in nephrotic patients or in rats, despite severe hypoalbuminemia. Although dietary protein supplementation may lead to positive nitrogen balance, dietary protein supplementation alone does not cause an increase in serum albumin concentration or body albumin pools, and may instead cause further albumin pool depletion because of changes induced in glomerular permselectivity. The use of angiotensin-converting enzyme inhibitors may blunt the increased albuminuria caused by dietary protein supplementation and allow albumin stores to be increased.

Perioperative nutritional support in the cancer patient

Cancer patients in whom elective surgical intervention is planned are frequently malnourished. Moreover, the tumor itself may be responsible for additionally altering metabolism in the host, although the mechanisms by which this occurs are not clear. All preoperative cancer patients should be carefully surveyed for indices of malnutrition. Patients with a history of inadequate oral protein and calorie intake, an unintentional weight loss of greater than 10 pounds, or a serum albumin level of less than 3.5 gm per dl should undergo a thorough nutritional assessment, including anthropometric measurements, 24-hour urinary urea nitrogen and creatinine measurements, and recall skin antigen testing. Surgical risk may be predicted by using indices that are sensitive and specific in assessing preoperative parameters of malnutrition. Adequate nutritional support for 7 to 10 days prior to surgery should be provided to all patients falling into the high-risk category and has been shown to significantly reduce the rate of postoperative complications and death in this group. Generally, a serum albumin of less than 3 gm per dl, a recent unintentional weight loss of greater than 10 to 15 per cent of normal body weight, and/or skin test anergy should be considered to designate high risk. In the formulation of a nutritional plan, estimates of daily energy requirements are essential and can be made by use of the Harris-Benedict equation, metabolic cart measurements, and perhaps 24-hour urinary creatinine values. Generally, 30 to 45 kcal per kg of body weight with 1.2 to 1.5 gm of protein per kg of body weight daily, regardless of the route of delivery, will provide adequate nutritional support. Patients should be fed by the enteral route if possible. Although oral intake is preferable, many malnourished cancer patients will be unable to achieve necessary protein and calorie requirements in this manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Improved protein kinetics and albumin synthesis by branched chain amino acid-enriched total parenteral nutrition in cancer cachexia. A prospective randomized crossover trial

A prospective randomized crossover trial was conducted to determine the effect of a branched chain amino acid (BCAA)-enriched solution on whole body leucine kinetics and fractional rates of albumin synthesis in patients with intra-abdominal metastatic adenocarcinoma. Ten malnourished cancer patients were provided isonitrogenous amounts of both a conventional total parenteral nutrition (TPN) formula containing 19% BCAA and a BCAA-enriched TPN formula containing 50% of the amino acids as BCAA in a random order. Whole body protein turnover was determined by a 10 hour continuous infusion of leucine 14C. Increased whole body leucine flux (68 +/- 5 mumols/kg BW/hr versus 145 +/- 11; mean +/- SEM; P less than 0.001) and oxidation (13 +/- 2 mumols/kg BW/hr to 46 +/- 5; P less than 0.001) were determined on the BCAA-enriched TPN. Increased whole body protein synthesis (2.2 +/- 0.2 g protein/kg BW/day versus 3.9 +/- 0.3; P less than 0.005) and leucine balance (2.5 +/- 0.4 g leucine/d versus 6.5 +/- 0.6; P less than 0.001) were also observed in patients receiving the BCAA-enriched TPN solution. Leucine release from protein breakdown was not statistically elevated (1.65 +/- 0.18 g protein/kg BW/d versus 2.48 +/- 0.40; P greater than 0.05) but, incorporation of leucine 14C into plasma albumin was significantly elevated (2.37 +/- 0.23 mumols/g/hr to 4.21 +/- 0.33; P less than 0.001) when the patients received BCAA-enriched TPN. Despite the better leucine balance, the improvement in the 24-hour urinary nitrogen balance was not statistically significant (6.6 +/- 3.9 g protein/d versus 11.4 +/- 2.9; control versus BCAA-enriched; P = 0.15). BCAA-enriched formulas improve whole body leucine kinetics, fractional rates of albumin synthesis, and leucine balance, and thus may favorably influence protein metabolism in cancer cachexia.

Lack of modulation of postoperative immunosuppression by isotonic amino acid infusion

Effects of an isotonic amino acid solution on the immune defence systems of surgical patients were studied. Twenty-two patients admitted for major abdominal operations were randomly allocated into two groups. Eleven of them received 1 liter of 3% amino acid solution daily for 5 days postoperatively, while 11 control patients received balanced 5% glucose-containing electrolyte solutions. Immune variables were studied preoperatively and at 1, 3 to 4, and 6 to 7 days postoperatively. These studies included leukocyte and differential counts, T (OKT3+), B (sIg+), T helper/inducer (OKT4+) and suppressor/cytotoxic (OKT8+) cell determinations, measurement of in vitro lymphocytic responses to phytohemagglutinin (PHA), pokeweed mitogen (PWM) and Staphylococcus aureus Cowan I (StaCw) in cultures of separated lymphocytes, and to PHA, concanavalin A (Con A), and PWM in whole blood cultures. B lymphocyte functions were studied by measuring synthesis of immunoglobulins IgG, IgM, and IgA in the cell culture medium when lymphocytes were stimulated with PWM alone and in the presence of Con A or hydrocortisone. Postoperative amino acid infusion slightly improved the capacity of lymphocytes to synthetize and secrete IgG and IgM. By contrast, no improvement was seen in cell counts or lymphocyte transformation patterns.

Post operative stimulation of cell mediated immunity

The consequences of altered immuno-competence resulting from anaesthesia and surgery are potentially hazardous to the patient with malignant disease. Malnutrition also produces reduction in cell mediated immunity, a condition which is commonly incurred in patients with neoplastic disorders. Numerous agents have been claimed to stimulate the immune responses but few have proved to be of practical value. This paper reports the use variously of protease inhibitors, using Aprotinin, and post operative nutritional therapy, following major surgical resection for carcinoma - specifically as regards their influence on parameters believed to relate to cell mediated immunity. No clinical, metabolic or immunologic benefit was identified from either method of post operative stimulation of cell mediated immunity, although this study did confirm post operative depression of these parameters. The significance of these changes is unclear but there is no evidence to support an immunological mechanism for either of these approaches being of benefit in clinical practice.

Use of urea kinetics in the nutritional care of the acutely ill patient

In acutely ill patients nitrogen balance is often assessed clinically from measurements of protein intake and urinary urea nitrogen. We have utilized urea kinetic modeling to measure urea generation rates, protein catabolic rates and nitrogen balance in 19 acutely ill patients with varying degrees of renal dysfunction and have studied the effect of varying caloric intake on protein balance during a period of fixed protein intake. In patients with measured creatinine clearances equal to or greater than 50 ml/min there was a highly significant correlation between nitrogen balance estimates derived from urea kinetic modeling and those obtained from urinary urea nitrogen (R = 0.939; p less than 0.001). When creatinine clearance measurements were between 20 to 50 ml/min the correlation between the two estimates was poorer (R = 0.337; p less than 0.001). In patients whose creatinine clearance was below 20 ml/min the correlation between measurements was worse still (R = 0.229; p less than 0.002). To determine the effects of increasing caloric intake on protein catabolic rate seven acutely ill patients were studied. When caloric intake was increased from 27.8 to 34.2 kcal/kg/day while on a fixed protein intake of 1.27 g/kg/day there was a significant fall in protein catabolic rate from 1.39 to 0.99 g/kg/day (p less than 0.002). As urea kinetic modeling takes into account changes in blood urea nitrogen, extrarenal losses of urea and the urinary urea pool, it is the preferred method for measuring protein balance in acutely ill patients particularly those with poor renal function. Serial monitoring of protein catabolic rates permits easy continuous assessment of the effect of increasing caloric intake on protein sparing during parenteral hyperalimentation.

The effect of isotonic amino acid infusions on serum proteins and muscle breakdown following surgery

Twenty patients undergoing major surgical procedures received constant infusion (21/day) of either 3.5 per cent amino acid (AA) or 5 per cent dextrose (D5W) solutions in addition to other fluid requirements for 4 postoperative days. Ketosis was evident in AA patients as a mean daily beta-hydroxy butyrate excretion of 2.16 +/- 1.39 mmol and respiratory quotient of 0.708 +/- 0.013 compared with 0.28 +/- 0.45 mmol/day and 0.754 +/- 0.015 respectively in the D5W group. The serum total protein and albumin concentrations (but not those of transferrin and prealbumin) were significantly higher in the AA than the D5W group on day 4. However, the mean fluid balance for days 3 and 4 was significantly less positive in AA patients. The mean daily nitrogen balance of -6.6 +/- 7.7 gN/day in AA patients and -9.5 +/- 5.8 gN/day in D5W patients was not significantly different. Mean daily 3-methyl histidine excretion (38.2 +/- 12.3 mumol/mmol creatinine) in AA patients was significantly higher than in D5W patients (31.2 +/- 10.8 mumol/mmol creatinine). With no improvement in nitrogen balance, an increase in muscle protein breakdown and the possibility that decreased fluid retention explains the higher serum total protein and albumin levels, this study fails to demonstrate improved protein sparing by isotonic amino acid infusions following surgery.

Effects of carbohydrate-containing and carbohydrate-restricted hypocaloric and eucaloric diets on serum concentrations of retinol-binding protein, thyroxine-binding prealbumin and transferrin

The effects of diet on the serum concentrations of albumin, transferrin, thyroxine-binding prealbumin (TBPA) and retinol-binding protein (RBP) were studied in 3 groups of obese subjects (Groups I-III) and 1 group of normal weight subjects (Group IV). Group I subjects ate either a 830 kcal carbohydrate-containing diet (CCD) or carbohydrate-restricted diet (CRD), Group II and III subjects ate a hypocaloric CRD. Subjects in Group IV ate a eucaloric CRD. Serum albumin concentrations did not change in any of the 4 groups. Only the subjects in Group II had a statistically significant decrease in serum transferrin concentration 6 wk after starting the hypocaloric, CRD. Group I individuals eating the CRD and the subjects in Groups II, III and IV had significant decreases in the serum concentrations of TBPA and RBP after 1 wk which persisted without further change during the remaining 3-5 wk of the diets. Group I subjects eating the CCD had a significant decrease in TBPA concentration at 1 and 6 wk. The RBP serum concentration was significantly decreased after 1 wk on the diet, but was not significantly different from the control diet period at 6 wk. The magnitude of the decreases in serum concentrations of TBPA and RBP in the Group I subjects eating the CRD were significantly greater than in the Group I subjects eating the CCD. Thus, ingestion of a hypocaloric, CRD by obese individuals results in decreased serum concentrations of TBPA and RBP. Isocaloric substitution of carbohydrate for fat reduces this effect. Dietary carbohydrate apparently modulates the serum concentrations of TBPA and RBP, independently of caloric intake, since ingestion of a eucaloric CRD by normal weight individuals also decreased the serum concentration of the two visceral proteins.

The effects of nitrogen and energy intake on the metabolism of normal, depleted and injured man: Considerations for practical nutritional support

This article illustrates how the nutritional and metabolic effects of a range of protein and energy intakes depend on the clinical state of the patient and how these considerations may be used to provide guidelines for nutritional support. First, it is necessary to define states and mechanisms of malnutrition and then discuss the biochemical processes which underlie nutritional rehabilitation.

The metabolic effects of isotonic amino acid infusion in surgical sepsis

28 normally nourished adult male and female patients who had undergone major elective surgery were maintained on dextrose-free isotonic amino acid solutions as their sole nutritional support. In the 6 days after surgery, 15 patients had no septic complications, 9 developed superficial sepsis, and 4 developed a deep seated collection of pus or deep sepsis. Patients without infection developed and maintained a fasting metabolic fuel profile within the first 3 days and increasingly spared protein. Superficial sepsis caused a small depression in serum ketone body concentrations but did not otherwise alter the fasting profile. Moreover nitrogen balances and plasma albumin and transferrin concentrations were unaltered by superficial sepsis which is not the response usually recognised with infection. Metabolic adaptation to the fasting state was lost in patients with deep sepsis and nitrogen losses were increased with greater decreases in plasma albumin and transferrin.

Prognostic nutrition factors in lung cancer patients

To examine the effect of nutritional support via intravenous hyperalimentation (IVH) on tolerance, response, and survival, a prospective study of patients with adenocarcinoma of the lung receiving chemotherapy with or without IVH was undertaken. Results indicated a more favorable survival in patients with a greater than 74% initial triceps skinfold and a less than 4% initial weight loss. The effect of IVH was reflected by greater weight gain in those patients receiving nutritional support 10 days prior to chemotherapy or simultaneous with chemotherapy; however, IVH had no significant advantage to improved survival or response.

[Protein-sparing effect of various types of peripheral parenteral nutrition]

A randomized clinical study was performed postoperatively in a total of 47 patients comparing three different concepts of peripheral parenteral nutrition. Substituting 1 g amino acids (AA)/kg b.w. daily, the amount of carbohydrates (CH) was changed solely: gr. II no carbohydrates (sole AA-substitution), gr. III 2 g CH/kg b.w. (hypocaloric nutrition) and gr. IV 5 g CH/kg b.w. (basic nutrition). The influence on protein metabolism was examined by cumulative N-balances, various plasma proteins viscerally synthesized and serum amino acids predominantly utilised in peripheral tissues. In comparison to a non-fed-control group (I), hypocaloric nutrition showed the qualitative most favourable protein-sparing effect. Besides, 87% of N-retention serum levels of plasma proteins and amino acids investigated could be normalized completely. Peripheral basic nutrition also had a 88% rate of N-retention, however, only peripherally utilised amino acids were influenced beneficially whereas the plasma proteins remained depleted. Sole AA-substitution neither affected amino acid levels nor plasma proteins, and the N-retention rate was significantly lowered (67%). Possibly this type of therapy increases protein turnover solely, while true protein-sparing took place only with additional CH supply. However, a positive effect on visceral protein synthesis was observed exclusively with hypocaloric nutrition.

Parenteral nutrition by peripheral vein

Peripheral parenteral nutrition can provide perioperative nutritional support to patients with inadequate oral intake in whom total parenteral nutrition with hypertonic dextrose administered by a central vein cannot be undertaken because of sepsis, subclavian vein thrombosis, or lack of expertise and familiarity. Peripheral parenteral nutrition may be indicated in patients with marginal nutritional status whose postoperative course and period of starvation are unpredictable and in patients being started on a total enteral nutrition regimen. In patients with increased requirements because of stress or malnutrition who need full nutritional support by a peripheral method, the lipid system is indicated. In certain instances, large enough volumes can be infused to provide sufficient calories and protein for nutritional repletion. Protein-sparing therapy is indicated for nutritional maintenance in patients who do not clearly require full support by total parenteral nutrition but who are taking insufficient calories and protein orally. Peripheral parenteral nutrition avoids the risks of subclavian vein catheterization but requires that adequate peripheral veins are available. The metabolic complications are minimal compared with those of total parenteral nutrition, and the nutritional management of the diabetic patient is greatly simplified. Several techniques of preserving peripheral veins and prolonging their use have been discussed.

Albumin in TPN solutions: potential savings from a prospective review

As a result of the common usage of albumin in total parenteral nutrition (TPN) solutions at The Ohio State University Hospitals, a review of the use of this product was performed. Albumin therapy in 18 patients was evaluated using prospective criteria. Therapy was considered appropriate if the serum albumin level was less than or equal to 3.0 g%. Using these criteria, 12 of 18 patients (67%) received albumin in the TPN solution. Of these 12 patients, 7 received albumin unnecessarily. During the 3-week review, a total of 168 vials of 50 ml, 25% albumin (2100 g) were administered to patients with serum albumin concentrations greater than 3.0/100 ml at a cost of $6,014. Over a year, this could mean over $100,00 in costs which could be eliminated. Criteria for use of albumin in malnourished patients receiving TPN are not well established. This study demonstrated that developing simple criteria for the prospective review of albumin in TPN solutions and using them to monitor albumin therapy closely, can result in very significant cost savings to patients receiving TPN.

Protein-sparing therapy during pneumococcal infection in rhesus monkeys

A model was developed in the rhesus monkey to determine if the marked wasting of body proteins associated with sepsis could be prevented by an intravenous supply of various nutritional substrates. All monkeys were given a basic infusion of 0.5 gm of amino acid nitrogen/kg body weight via an indwelling catheter in the jugular vein. Three groups were given diets with no added calories, 85 calories/kg from dextrose or 85 calories from lipid. In each group, six monkeys were inoculated with 3 x 10(8) Streptococcus pneumoniae and four with heatkilled organisms. In the monkeys infused with the amino acids alone, pneumococcal sepsis resulted in a fourfold increase in loss of body proteins compared with calorie-restricted controls. Addition of 85 calories/kg/day of either dextrose or lipid reduced body wasting associated with infectious disease. The calories from lipid were utilized bythe septic host as a source of energy, with a slightly reduced efficiency when compared with the isocaloric infusion of dextrose. The nitrogen sparing of the fat emulsion could not be accounted for by its glycerol content. Therefore, the septic monkey seemed to utilize fatty acids as an energy substrate. It appears that the carbohydrate calories tend to favor the synthesis of peripheral proteins (associated mainly with skeletal muscle), while lipid calories favor synthesis of visceral proteins such as plasma albumin and acute-phase proteins.

Protein-sparing in cystectomy patients

Forty-four patients undergoing radical cystectomy and urinary diversion for invasive bladder cancer were studied prospectively in order to evaluate the substitution of crystalline amino acids (A3W) for dextrose (D5W) in their postoperative fluid management. Nutritional assessment revealed 17 (39%) patients to be malnourished prior to operation; the postoperative complication rate in Group I (D5W) was 33% vs 17% in Group II (A3W). Nitrogen losses in both groups were low, secondary to the large amounts of albumin used postoperatively; however, more exogenous albumin was needed after operation to maintain serum albumin levels in Group I compared with Group II (77.5 +/- 3.1 gm vs 65 +/- 5.2gm). Cell-mediated immunity, determined by reactivity to a battery of recall antigens, revealed that 56% (5) of Group I patients were able to maintain their skin test reactivity throughout the postoperative course compared with 94% (17) in Group II. Four nutritionally depleted patients in Group I required conversion to a forced feeding regimen (IVH), while none of those in Group II required a change in nutritional regimen. Invasive bladder cancer represents a major injury, and preoperative x-ray therapy along with surgical extirpation is associated with considerable nutritional depletion. Early nutritional support in the management of these patients is mandatory, and where hypocaloric feeding regimens are appropriate, the use of A3W in place of D5W solutions would appear to be indicated.

Optimal nutritional support in surgery for bladder cancer: preservation of visceral protein by amino acid infusions

Seventeen patients undergoing 19 major urological operations for bladder cancer or rectal leiomyosarcoma (1 case) were studied after randomization for 3 hypocaloric dietary regimens, preoperative keto-adaptation by a carbohydrate-free, oral protein diet continued in the postoperative period by isotonic amino acid infusions, postoperative amino acid infusions only and 5 per cent dextrose infusions. In these normally nourished patients serum transferrin (plus 13 mg./dl. minus 30 mg./dl., minus 69 mg./dl., p less than 0.05 for the first and combined amino acid groups against the third group) and 2 other short half-life hepatic secretory proteins, prealbumin and retinol-binding protein, represented sensitive indexes of visceral protein and nutritional support, superior to nitrogen balance, anthropometric assays, delayed hypersensitivity skin test reactivity and serum albumin. Near isotonic amino acid infusions were more effective in preserving visceral protein status than 5 per cent dextrose but preoperative keto-adaptation was not shown to have any increased benefit over protein-sparing therapy given only after an operation.

Changes in protein synthesis after trauma: importance of nutrition

The effect of trauma (femur fracture) on protein synthesis in rats given four different parenterally administered nutrient formulations ("diets") was investigated. Diet I was a maintenance formulation. It contained sufficient amino acids and glucose to keep the rats in nitrogen balance but was inadequate to support growth. Diet II was amino acids only, diet III was severely hypocaloric glucose, and diet IV was diet I minus the amino acids. The rats received parenterally all nutrients for the duration of the 4-5 day study. Twenty-four hours posttrauma, the fractional synthesis rates of liver, lung, heart, kidney, and muscle were estimated by infusing [15N]glycine for 17.5-19 h. (T.P. Stein, J.C. Oram-Smith, M.J. Leskiw, H.W. Wallace, L.C. Long, and J.M. Leonard. The effects of protein and calorie restriction on protein synthesis in the rat. Am. J. Physiol. 230: 1321-1326, 1976.) Two trends were found: i) on the amino acid-containing diets (I and II), most protein synthesis rates were increased posttrauma. Lung was the exception: no change was found; ii) rats on the amino acid deficient diets (III and IV) showed a decrease in the fractional muscle and lung synthesis rates posttrauma. We concluded that in this rat trauma model the requirement is mostly for amino acid nitrogen posttrauma.