Stimulation of protein, RNA, and nucleotide synthesis in lymphocytes after abdominal surgery is not affected by postoperative amino acid supply.

The effects of abdominal surgery on protein, RNA, and de novo purine nucleotide synthesis in lymphocytes, and modification of these changes by postoperative amino acid supply, were investigated in 24 patients undergoing cholecystectomy (n = 12) or removal of gastric cancer (n = 12). Mono-nuclear cells were isolated from the peripheral venous blood and incubated with radioactive tracers in vitro. Protein and RNA synthesis, as measured using [14C] glycine and [3H]uridine, respectively, increased postoperatively. Nucleotide synthesis determined by the incorporation of radioactivity from [14C] glycine into nucleotides increased simultaneously. The concentration of 5-phosphoribosyl 1-pyrophosphate (PRPP) estimated by the incorporation of [14C]adenine into nucleotides also increased. These changes were greater and of longer duration in patients with cancer operation than in those with cholecystectomy. In neither case were they affected by the amount of amino acid intake, or increases in energy intake. These results suggest that abdominal surgery stimulates protein and ribonucleic acid (RNA) synthesis in lymphocytes. Increased RNA synthesis may be ensured by increased synthesis of nucleotides, and increased PRPP concentrations appear to regulate the rate of nucleotide synthesis. The responses are apparently dependent upon the severity of surgery, but unrelated to the amount of amino acid supplied postoperatively.

Migration of a Silastic central venous catheter into the right jugular vein: report of two cases.

Silastic catheters commonly used for total parenteral nutrition have advantages including low rates of infection and thrombosis. However, because of flexibility they produce an unusual problem, catheter tip migration. We present two cases of catheter migration into the right jugular vein. In one case, infusion phlebitis developed which required repositioning over a guidewire, and in a second a spontaneous correction occurred.

Anaesthesia, not surgical stress, induces increases in serum concentrations of reverse triiodothyronine and thyroxine during surgery.

Effects of anaesthesia on serum concentrations of thyroid hormones during and soon after abdominal surgery were examined in 29 patients undergoing cholecystectomy (n = 22) or removal of gastric cancer (n = 7). They were given one of the following anaesthetics in combination with nitrous oxide in oxygen: epidural bupivacaine, enflurane, pentazocine, ketamine, halothane, epidural bupivacaine and enflurane. Regardless of type of anaesthesia, T3 decreased significantly during and after surgery. T4 and rT3 increased markedly when either enflurane or halothane was given but not with the other anaesthetic agents; they then decreased toward pre-surgical levels after surgery. There was no correlation between changes in rT3 and those in cortisol or free fatty acids. TSH fluctuated little. These results show that the increases in rT3 and T4 during and soon after surgery are due not to surgical trauma but to inhalational anaesthetics such as enflurane and halothane.

Effects of glucose on fuel utilization and glycerol turnover in normal and injured man.

Rates of fat mobilization (glycerol turnover), and fuel utilization and energy expenditure (indirect calorimetry) were measured in normal subjects and injured or septic patients maintained on high or low iv intakes of glucose as their sole nutrient source during 3-day periods. Regimens were given consecutively to each subject in random order. Concentrations of glucose, glycerol, fatty acids, 3-hydroxybutyrate, urea, insulin, and glucagon were determined in plasma, and of epinephrine and norepinephrine in urine. In normal subjects, there was no increase in energy expenditure with increasing glucose, although estimated costs of glucose storage as glycogen or fat could account for an increase of 4%. Thus, storage costs of glucose do not necessarily constitute an obligatory increase in energy expenditure. Rates of glycerol turnover and fat oxidation, and plasma glycerol concentrations were lower with the high than the low rate of glucose infusion, and lower than values reported by others during fasting or glucose infusion. Rates of fat oxidation were higher and glucose oxidation lower in patients than in controls, even though insulin concentrations were more than twice as high in patients. This confirms previous studies comparing injured and septic patients to depleted patients or historical controls. Triglyceride cycle activity was higher in the injured and septic patients than in normal subjects, and could account for from 6% to 15% of the increase in energy expenditure, in agreement with reports for burn patients.

Stimulation of de novo biosynthesis of purine and pyrimidine nucleotides in the liver of rats following burn injury.

Third-degree burn injury covering 25% of the body surface was imposed on rats. The de novo biosynthesis of purine and pyrimidine nucleotides in the liver of these rats was measured by the incorporation of labeled glycine and bicarbonate into the respective bases. They were increased one day after injury (day 2) and returned to the control values three days after injury (day 4). As expected, the metabolic flow through 5-phosphoribosyl l-pyrophosphate (PPRibP), estimated using [14C]ribose as a tracer, varied in a similar manner. The activities of glutamine phosphoribosylpyrophosphate amidotransferase and carbamoyl-phosphate synthetase II on day 2 did not change significantly. The nucleotide concentrations, effectors of the enzymes, also did not change significantly. The concentrations of PPRibP on days 2 and 4 were 85% higher (P less than .02) and similar to that of controls, respectively, and the elevated concentration was a major factor responsible for the increased nucleotide biosynthesis. Increased synthesis caused the elevation of PPRibP concentrations. There were, however, no significant changes in the factors so far known to regulate PPRibP synthesis.

Short-term effects of varying glucose intake on body composition of malnourished adult patients.

Changes in weight and body content of protein, carbohydrate, fat, total body water, intra- and extracellular water, Na, and K were estimated from balance measurements in malnourished adult patients receiving total parenteral nutrition for consecutive 8-day periods, containing either a low or high carbohydrate content. Total caloric intake was 65% of energy expenditure on the low intake and 119% on the high intake, with a difference of 54% due entirely to carbohydrate. Although there are many assumptions and approximations necessarily involved in multiple balance studies, the accuracy is sufficient to produce useful information in short-term studies of this type. It is particularly useful in looking at differences between diets, since most of the methodologic errors cancel out. The effect of the increased glucose intake was to significantly increase storage, or decrease loss, of fat, carbohydrate, protein, intracellular water, and K. Changes in Na and extracellular water varied widely among patients, but were not affected by the increase in glucose. Most of the increase in K content (83%) was associated with glycogen deposition; a much smaller amount (17%) was associated with protein deposition. Thus, the ratio of K/N deposited (15 mEq of K:1 g of N) was very different from the 3:1 ratio seen in most tissues. Changes in any one constituent of body cell mass may not, therefore, be good indicators of changes in another. Since protein is the most important active component of body cell mass, changes in body cell mass components other than N should be interpreted with caution when used as indices of nutritional therapy.

Effects of increasing glucose intake on nitrogen balance and energy expenditure in malnourished adult patients receiving parenteral nutrition.

The effects of increasing glucose intake on nitrogen balance, energy expenditure and fuel utilization were measured in malnourished adult patients receiving parenteral nutrition with constant nitrogen intake and high or low glucose intakes for 8 day periods. Energy balance, nitrogen balance, weight and temperature were determined daily. Blood samples taken at admission and at the end of days 7 and 8 of each diet were analysed for glucose, fatty acids, urea, insulin, glucagon and thyroid hormones. The effect of increasing glucose intake was to increase nitrogen balance by 0.28 +/- 0.08 (SEM) mg/kJ. A scheme is proposed, based on present and previous findings, of the separate effects of nitrogen and energy intake on nitrogen balance, permitting calculation of rates of repletion of fat and lean body mass from estimates of nitrogen intake and energy balance. Malnourished patients are shown to attain markedly positive nitrogen balances at zero or negative energy balances. Large errors in estimation of energy requirements have little effect on nitrogen balance. Changes in nitrogen balance were entirely due to changes in urea excretion. Creatinine excretion increased 12% with high glucose intake, attributed mainly to increased muscle mass (7%) and body temperature (4%). A 12% increase in resting energy expenditure was only partly due to costs of glycogen storage and lipogenesis; the remainder, about one-half, is probably due to glucose and insulin mediated increases in sympathetic activity. There were marked increases in 3,5,3'-triiodothyronine (T3) concentrations with time, but no difference between the high and low glucose diets. The T3/thyroxine ratio, an index of free T3 concentration, increased much more rapidly on the high than on the low glucose diet. Changes in T3 could not account for the effect of glucose, under these conditions, to increase resting energy expenditure.

[Whole body protein turnover, synthesis and breakdown in patients receiving total parenteral nutrition (TPN) before and after recovery from surgical stress].

This study was conducted to clarify the mechanisms underlying the loss of body nitrogen after trauma. Six patients who underwent abdominal surgery and six for control were studied. The measurement of whole body protein turnover was made on the third and tenth postoperative day during TPN with constant infusion of [15N] glycine according to Picou and Taylor-Roberts. The measurement was also made on six control patients during TPN in non-stressed state. The rates of whole body protein turnover (Q), synthesis (S) and breakdown (B) were calculated from the plateau 15N enrichment of urinary total N, which was analyzed with a mass spectrometer. The values were compared with control and the changes in the individual patients were examined by a paired t-test. Immediately after operation, Q and B were significantly elevated (p less than 0.05 and p less than 0.02, respectively), and reduced with the improvement of N-balance after recovery from stress by 0.95 +/- 0.21 and 0.61 +/- 0.13 g X protein/kg X day, respectively. The changes in Q and B were statistically significant (p less than 0.005 and p less than 0.005, respectively). Whereas, no tendency of alteration in S was found throughout the study. It is concluded that protein turnover rate increases in surgical stress, and that the increased protein catabolism rather than the alteration in synthesis could account for the postoperative nitrogen losses.

Effects of intravenous infusion of a ten percent soybean emulsion on hormones, amino acids and other substrates in blood.

Acute responses in hormone and substrate concentrations to intravenous administration of a fat emulsion were studied in metabolically normal subjects. Eight subjects were infused with either a fat emulsion or an aqueous solution of glycerol for 3 h. Serum triglycerides (TG), free fatty acids (FFA), glucose, glycerol, 3-hydroxybutyrate (3-OH butyrate), insulin, thyroid hormones, plasma glucagon, norepinephrine, and amino acids were measured. The infusion of a fat emulsion induced a 30% increase in glucose and a 22% decrease in alanine together with significant elevations of TG (> 10 mM) and FFA (> 1 mM). A small increase in insulin (4 microU/ml) and a reduction in glucagon (40 pg/ml) were observed. Eight-fold increases in glycerol occurred with both the fat emulsion and glycerol infusions. The administration of a fat emulsion resulted in a 4-fold increase in 3-OH butyrate, whereas glycerol infusion reduced its level by 50%. Glycerol infusion produced no measurable effects on the substrates other than glycerol or 3-OH butyrate. No significant changes were observed in thyroid hormones or norepinephrine after either solution was given. The data suggest that acute elevation of FFA by means of intravenous fat emulsions leads to preferential oxidation of FFA and stimulates hepatic ketogenesis with resulting glucose conservation as well as inhibition of alanine production without many alterations in hormonal concentrations.

Protein-diet-induced elevation of 5-phosphoribosyl 1-diphosphate concentrations in mouse liver associated with increased syntheses of various nucleotides and the possible involvement of glucagon.

Postprandial elevation of 5-phosphoribosyl 1-diphosphate (PPRibP) concentration in the mouse liver (Lalanne, M. and Henderson, J.F. (1975) Can. J. Biochem. 53,394-399) was further studied regarding the effects of protein intake and the underlying mechanisms. The extent and duration of the increase depended on the quantity and quality of proteins ingested. The order of effectiveness of various diets was as follows: 60% casein greater than 20% egg albumin greater than 20% casein greater than 20% gelatin = 20% gluten greater than 20% zein greater than 0% casein. Hepatic purine and pyrimidine biosyntheses de novo, as measured by labelled tracer incorporation, increased with increasing protein intake. Nicotinic acid incorporation into NAD increased equally, whether casein-containing or casein-free diets were given. Therefore, the increase of PPRibP level may be brought about by increase in its synthesis. Administration of glucagon or epinephrine similarly elevated the hepatic level of PPRibP. Somatostatin, known to inhibit secretion of pancreatic hormones, suppressed the casein-diet-dependent PPRibP level increase. Colchicine markedly inhibited the casein-diet- and glucagon-dependent responses, but not the epinephrine effect. It is likely that glucagon is a major factor in mediation of the protein-diet-dependent PPRibP level increase and that the cytoskeleton is involved in the glucagon-mediated response.

Protein synthesis rates in rat muscle and skin based on Lysyl-tRNA radioactivity.

Measurement of protein synthesis in individual organs is important in understanding metabolic changes in injury, sepsis, or starvation. Methods, mostly isotopic, for measuring synthesis are plagued by problems of experimental design and interpretation. Thus it is desirable to use a variety of methods based on different assumptions. The present study is the first to isolate radioactive aminoacyl-tRNA in the study of protein synthesis in muscle and skin. Male rats, 200-300 g, trained to eat chow for 4 hr/day were studied at 2 hr (absorptive) or 16 hr (postabsorptive) after a meal. Under ether anesthesia, a tracer dose of L-[4-5-3H(N)]-lysine was infused at a constant rate. At 20, 30, or 40 min 1 ml of arterial blood was withdrawn and 2-g samples of skin and thigh muscle were quickly excised and frozen. Samples were pooled from 4 to 7 rats for each infusion period. Concentrations and specific activities were determined for plasma lysine, and for free, tRNA, and protein-bound lysine in muscle and skin. Protein renewal rates in absorptive and postabsorptive periods averaged 6 and 9% per day in muscle, and 20 and 35% in skin. The data for muscle confirms results of other methods and suggests little contribution of rapidly turning over protein. The contribution of skin to whole body protein synthesis, about 500 mg . 100 g-1 . day-1, is similar in magnitude to the contributions of muscle, liver, or intestine.

Metabolic and endocrine effects of fasting followed by infusion of five-percent glucose.

Isotonic glucose is often the sole nutrient provided to hospitalized patients with varying degrees of protein calorie malnutrition. To study the effects of such diets uncomplicated by illness, normal human subjects were fasted (6 to 14 days) before receiving an infusion of 5% dextrose (5 to 7 days). Norepinephrine excretion rose steadily-to six times control values-during the first 6 days of the fast and changed little thereafter. It remained high during the first 3 days of glucose infusion and subsequently returned toward normal. The rate of NTau-methylhistidine excretion changed little during the fast but decreased abruptly with glucose infusion. The magnitude of NTau-methylhistidine excretion indicated that undirectional muscle protein degradation was about equal to nitrogen excretion during the fast, and that the decrease in muscle protein degradation could account for the abrupt decrease in nitrogen excretion (from 91 to 30 mg N/kg . day) after glucose infusion. This suggests that the conservation of muscle protein caused by glucose infusion in this setting is affected by decreased degradation rather than by increased synthesis. Changes in NTau-methylhistidine excretion and total nitrogen excretion were more rapid than, and therefore not mediated by, changes in insulin concentration or norepinephrine excretion.