Past and current trends in soy supplementation: a bibliographic study

The aim was to determine in what areas the therapeutic application of soy predominates in clinical trials and to assess the emerging fields of its use by means of an analysis of bibliographic resources. A search was performed in the MEDLINE database up to 31 december 2004, limited to the Title/Abstract field, and Clinical Trials as the type of publication. The abstracts from the publications selected (n=86) were reviewed and different variables were assessed. A total of 3280 subjects were included: 15% men and 59% women (71% postmenopausal). The studies were performed basically in healthy individuals (71%). Twenty five percent of the studies investigated plasma levels of different metabolites and 21% determined hormone or lipid profiles. After the year 2000 a new population focus was detected, with the publication of two studies in elite gymnasts and judoists, with positive results. The present observations indicate that soy supplementation in the competitive sports elite may be an emerging application.

[Preoperative chemotherapy and total parenteral nutrition in colon cancer]

AIM

The objective of this study was to determine the effect of TPN after surgery in patients with colon carcinoma and preoperative chemotherapy.

MATERIAL AND METHOD

The study included 27 patients, 16 men and 11 women, with a mean age of 62.1 +/- 11.2 years. The patients were divided into two groups according to whether they had undergone chemotherapy (Group A; n = 11) or not (Group B, control; n = 16) prior to surgery. Almost two thirds of the patients were in stage III of the disease. Among those receiving this treatment, 60% were given 5-fluorouracil plus leucovorin at a dose of 5.5 +/- 2.7 cycles/patient and the others received different regimens. TPN was established early with a mean of 11.7 +/- 9.2 days. The clinical and nutritional assessment was performed before surgery and at the end of TPN administration.

RESULTS

The mean body mass index (BMI) was 24.1 +/- 2.2 kg/m2. Comparison between the groups before the start of TPN showed statistically significant differences in red blood cell and platelet counts (P = .013 and P = .02, respectively). These differences had disappeared at completion of TPN, suggesting that this treatment can reverse the hematological changes induced by chemotherapy.

CONCLUSION

In patients who receive chemotherapy before surgery and in whom TPN it was indicated the combination of these two treatments could be beneficial.

Dipeptidyl-peptidase IV in patients with short bowel syndrome

BACKGROUND & AIMS

The aim of this study was to determine serum dipeptidyl peptidase IV (DPP IV) levels in a population of short bowel syndrome (SBS) patients, who had achieved intestinal adaptation.

METHODS

DDP IV reference values were determined in a healthy population (n=47). The SBS study group consisted of 30 patients (17 men, 13 women; 53.2+/-13.2 years). The criteria for inclusion were a remnant small bowel <200cm with or without colon resection. The time interval between resection and DPP IV measurement was >24 months except in 4 patients, in which it was 13-24 months (total mean: 64.7+/-47.3 months). Nutritional support was exclusively oral in 17 patients, oral plus cyclic TPN in 12 and TPN alone in one patient.

RESULTS

The reference range for DPP IV was 10-23U/l (mean: 16.01+/-3.2). In the group of SBS patients, mean serum DPP IV was 14.02+/-3.6U/l and mean body mass index 22.07+/-4.1kg/m(2). Eleven patients (36.6%) had hyperphagia and mean DPP IV in this group was 15.2+/-4.9U/l.

CONCLUSIONS

Measurement of DPP IV levels in this limited series of SBS patients who had reached intestinal adaptation showed normal levels and did not provide additional clinical information. Further analysis in the earlier postoperative period will determine whether this enzyme has a role as an indicator of evolution in these patients.

[Ingestion of antioxidants and polyamines in patients with severe burns]

Starting the first 24 hours after burn injury, energy supply, antioxidants and polyamines were assessed in 25 severe burn patients (20 men and 5 women) with a mean age of 45.6 +/- 20.4 years. Nutritional assessment was performed at 7, 15 and 21 days and was compared with a control group (n = 30). In 21 patients the burned body surface area was 20%-50% and in four patients it was greater than 50%. A mean decrease in energy supply of approximately 40% versus the calculated theoretical value was found in the three periods: 1,186 +/- 32; 1,117 +/- 589 and 1,331 +/- 578 kcal. In the first 15 days antioxidant ingestion was slightly lower than the recommended daily allowance for vitamin C: 60 mg versus 57 +/- 32, 57 +/- 53 and 75 +/- 53 mg, and was lower during the entire period for vitamin E: 10 mg versus 5.0 +/- 2.9; 4.5 +/- 3.0 and 5.3 +/- 3.4 mg; selenium: 40 microg versus 22.8 +/- 13.7; 22.5 +/- 9.8 and 25.7 +/- 11.2 microg and zinc: 12 mg versus 7.3 +/- 3.0, 6.8 +/- 4.8 and 8.4 +/- 5.3 mg. Taurine ingestion decreased on day 15 and significantly increased on day 21: 65.7 +/- 30 mg, 50.9 +/- 25 and 72.0 +/- 29 mg (p < 0.05). Ingestion of total polyamines did not differ significantly from the values observed in the control group and were as follows: day 7, total 45.2 +/- 23.0 umol, putrescine 16.7 +/- 10.2, spermidine 13.5 +/- 7.6 and spermine 13.6 +/- 8.8; day 15: total 41.1 +/- 38.5 and 14.9 +/- 4.0, 11.7 +/- 9.4 and 10.89 +/- 9.0; day 21: total 39.1 +/- 35.3 and 15.4 +/- 16.9, 12.3 +/- 11.4 and 17.3 +/- 16.8 umol, respectively.

Validation of an in vitro nutrition model using an enteral formula in aged neutrophils

The aim of the study is to validate a cell culture model appropriate for assessing the effects of standard nutritional formulas on neutrophil functionality in vitro. The model consists of aged cells exposed to a commercial nutritional formula containing solely LCT as lipid component. Preliminary experiments determined dosage of formula and culture interval. Neutrophils were isolated from a pool of whole blood in healthy volunteers (18-55 years old) and cultured with and without addition of a commercial enteral diet with 3.5% lipids (equivalent to 0.04, 0.08, 0.2 and 0.4 mM of intraassay LCT) for 18, 42 or 76 hours. Based on cell viability results, doses of 0.2 and 0.4 mM LCT and culture time of 18 hours were established for subsequent experiments. Neutrophil functionality was evaluated by phagocytosis (NBT test), MDA production (lipoperoxidation index) and DNA fragmentation. Optic microscopy showed higher percentages of pre-apoptotic cells and a significant increase in DNA fragmentation as compared to controls only with an LCT concentration of 0.4 mM (p < 0.05). Interestingly, cell cultures with both 0.2 and 0.4 mM of added LCT showed significant decreases in malonyldialdehyde (MDA) release as a lipoperoxidation marker. This nutrition model of neutrophils and in vitro complete enteral commercial diet is relatively simply to execute and can be applied to different pathological conditions in which the aim is to study changes in neutrophil functionality.

Effects of taurine on polymorphonuclear phagocytosis activity in burned patients

This study determines the effects of taurine (Tau) on phagocytosis of polymorphonuclear neutrophils (PMN) isolated from normal subjects (n = 41) and severely burned patients (n = 20). Phagocytosis was measured by nitroblue of tetrazolium (NBT) reduction in samples with and without latex bead stimulation. Taurine was added at doses of 0.2, 0.4, 0.8 and 1.6 mM to stimulated samples. In control cells there were statistically significant increases in phagocytosis after addition of Tau 0.8 mM and 1.6 mM to as compared to samples without Tau addition (295 +/- 23% and 330 +/- 35% vs. 248 +/- 18%; mean +/- S.E.; p < 0.05). A statistically significant increase in phagocytosis was observed in cells from the burned population after addition of Tau 1.6 mM (288 +/- 38% vs. 198 +/- 13%; mean +/- S.E.; p < 0.05). No changes in phagocytosis were found in cells from a subgroup of burn patients (n = 13) followed over 7, 15 and 21 days. These results indicate that taurine supplementation in vitro at doses of 0.8 to 1.6 mM improves the phagocytic capacity of neutrophils in healthy subjects and in patients with severe burn injury, mainly when neutrophil function is unaltered.

Plasma urea-cycle-related amino acids, ammonium levels, and urinary orotic acid excretion in short-bowel patients managed with an oral diet

BACKGROUND AND AIMS

The small intestine contains several enzymes involved in arginine synthesis and converts glutamine to citrulline, the major compound for endogenous arginine synthesis. This study was conducted to assess the plasma status of urea-cycle intermediates and orotic urinary excretion in short-bowel patients.

METHODS

Thirteen stable short-bowel syndrome patients (7 men; 60.2+/-15.2 years) were studied. Patients were divided into moderately resected (Group A; n=6) and severely resected (Group B; n=7) according to their remnant bowel length (Group A: 61-150 cm; Group B: < or =60 cm). All subjects were consuming an oral diet plus dietetic supplements. Plasma urea-cycle amino acids, ammonium and urinary orotic acid were determined.

RESULTS

Plasma glutamine levels were significantly higher in both patient groups than in the control group (P<0.001). Regarding citrulline, Group B levels were significantly lower vs. controls (P<0.001). Comparisons between patient groups showed higher arginine in Group A (P<0.05) and non-statistically lower citrulline in Group B. Blood ammonium and orotic urinary excretion were normal.

CONCLUSIONS

Although plasma citrulline and glutamine alterations were found, patients showed no hyperammonemia or orotic aciduria, which suggests a certain degree of adaptation in arginine and related amino acid metabolism, when an adequate dietary supply of arginine is provided.

Role of putrescine in cell proliferation in a colon carcinoma cell line

OBJECTIVES

Putrescine, the precursor for higher polyamine biosynthesis, is necessary for cell growth in mammals. Ornithine decarboxylase (ODC) activity and polyamine production are increased in neoplastic cells. Using colon cancer cell line derived from a tumor with high metastatic potential (CT-26), our objective was to study the effect of exogenous putrescine on ODC regulation, polyamine metabolism, and cell proliferation.

METHODS

Cells cultured with fetal calf serum were exposed to 100, 550, and 1000 microM putrescine for 24 h.

RESULTS

Intracellular free putrescine, determined by high-performance liquid chromatography, showed a statistically significant increase in exposed cells compared with controls and a significant correlation with levels of the metabolite present in the medium (r = 0.93; P < 0.001). Bromodeoxyuridine incorporation into newly synthesized DNA, a marker of cell proliferation, showed a statistically significant increase in the three putrescine groups as opposed to the control group. In samples with added aminoguanidine, significant increases in DNA synthesis were observed in the 550- and 1000-microM putrescine groups as opposed to the control group. Spermidine and spermine intracellular contents in all three putrescine-treated groups remained below control levels. No statistical differences in ODC enzymatic activity or ODC mRNA content were observed. Newly incorporated putrescine stimulated colon tumor cell growth.

CONCLUSIONS

Because neither enhanced conversion into the higher polyamines nor aminoguanidine inhibition of proliferation was observed, we suggest that this effect can be attributed to the putrescine molecule itself.

Antioxidant capacity in severely burned patients

Total antioxidant capacity (TAC) was measured after severe burns (non-electric with one exception) in two groups of patients: group A, 24 subjects (19 men and five women) 20-67 years old and group B, eight subjects (six men and two women) 20-54 years old, admitted to the Major Burns Unit of hospital general Vall d'Hebron over a period of nine months. Albumin, uric acid and antioxidant capacity analyses were carried out within 24 hours after injury in both groups, and additionally at 1, 7, 15 and 21 days in group B. Total antioxidant capacity was measured by inhibition of blue-green colour of the ABTS+ cation (600 nm) and compared with reference values obtained in healthy, sex and age-matched volunteers (n = 50). Results showed statistically increased mean antioxidant capacity values at 24 hours (Group A: 1.36 +/- 0.22 mmol/L; Group B: 1.66 +/- 0.39) as compared with reference values (range, 1.0 to 1.44 mmol/L), representing 42% of patients in group A and 50% in group B (overall mean 46%), with no correlation with severity of the burn. The longitudinal study (Group B) showed no correlation between total antioxidant capacity values and time (r = -0.171; ns). A statistically significant correlation was found between albumin and time (r = 0.438; p < 0.05), indicating a clear tendency toward normalisation of plasma albumin values during healing. There was no correlation among total antioxidant capacity, percentage of burned surface and clinical evolution, suggesting a poor sensitivity of the method for the study of this pathology.

Intestinal ornithine decarboxylase in short bowel syndrome patients with oral diet

The major consequence of extensive intestinal resection is loss of absorptive surface area, which results in malabsorption of nutrients; this condition is known as short-bowel syndrome (SBS). Patients with extensive small intestinal resection and colectomy leading to jejunostomy have the most severe SBS. Ornithine decarboxylase (ODC) plays a central role in cell proliferation and in the process of gut adaptation. Polyamine synthesis in crypt cells mediates the action of extracellular growth factors on DNA synthesis and mitotic activity. The aim of this study was to examine ODC expression and activity, diamine oxidase (DAO) activity and polyamine levels in the jejunal mucosa and red blood cells of SBS patients with a jejunostomy. The study group consisted of 6 patients (4 men and 2 women, mean age 55.8+/-9.8 years), who had undergone extensive small bowel resection and colectomy. All patients were maintained on cyclic parenteral nutrition and non-restricted oral nutrition. Two groups of patients operated on for unrelated reasons were included as the jejunum control group (n=6) and the ileum control group (n=13). Non statistical differences were observed in polyamine levels of red blood cells versus the control group (spermidine: 21.0+/-3.6 vs. 17.7+/-1.1 and spermine: 17.1+/-8.6 vs. 13.2+/-1.6 nmol/ml RBC, respectively). No significant decreases in putrescine and spermidine levels were observed between the groups, but spermine levels in SBS jejunum were significantly lower than the controls (P<0.05). In SBS patients a significant decrease in ODC and DAO activity were observed vs jejunum. A significant decrease in ODC-mRNA abundance was found for the SBS patients as compared to the two control groups (P<0.05). These results suggest that in SBS patients with jejunostomy intestinal adaptation may be impaired.

Serum leptin concentrations in patients with short-bowel syndrome

BACKGROUND

Short-bowel syndrome is a state of severe malabsorption resulting from absence or removal of the small bowel for several causes. A number of short-bowel patients develop hyperphagia. Leptin, a protein secreted from adipose tissue, signals the amount of energy stores to the brain.

OBJECTIVE

To study body composition and leptin regulation in short-bowel patients and to determine whether or not leptin concentrations are linked with hyperphagia.

DESIGN

We studied 25 short-bowel patients (remnant bowel less than 150 cm) and 31 controls and 10 oral nutrition. Fifteen patients received total parenteral nutrition and 10 oral nutrition. Anthropometric measurements, body composition (by bioelectrical impedance), and cholesterol, triacylglycerol and leptin concentrations were studied in all subjects.

RESULTS

There were no differences between short-bowel patients and controls in anthropometric variables, body composition, or leptin concentrations. Leptin concentrations were higher in short-bowel women than men (9.21+/-8.54 vs. 3.22+/-1.86 ng/ml, P=0.01). Leptin concentrations correlated positively with age (r=0.4, P=0.045), body mass index (r=0.52, P=0.007), fat mass (r=0.67, P=0.001) and body fat (r=0.68, P=0.0001); there were no correlations with other body composition parameters. We found no correlations between parenteral or oral nutrition and body composition parameters, or between leptin concentrations and the presence of hyperphagia. Logistic regression analysis showed that body fat correctly identified leptin concentrations in 60% of patients.

CONCLUSIONS

Body composition, leptin concentrations and leptin regulation in patients with short-bowel syndrome are similar to those of controls. Leptin concentrations do not correlate with hyperphagia in short bowel-patients.

[Polyamines in the gastrointestinal tract]

Polyamines are extremely important for cell growth, a fact that is reflected in the strict control of their synthesis and breakdown. In the small intestine, the polyamines play a fundamental role in all processes involving tissue regeneration, such as healing of stress-related ulcers, post-hepatectomy hepatic regeneration, adaptation syndrome after fasting and all processes with enterocyte hyperplasia or hypertrophy. In the gastrointestinal tract, there is a polyamine gradient in the villi-crypt cell axis and along the digestive tube, itself; the segments with greatest luminal content are the jejunum and the colon. Endogenous polyamine synthesis is stimulated by the diet and normal bacterial flora, which, in turn, regulate the amount and concentration of polyamines. Other hormonal and active peptide components (e.g. gastrin, epidermal growth factor, growth hormone) also have an influence on the pathway of polyamine synthesis. The interaction of these factors as related to the intestinal adaptive response is reviewed.

In vitro effects of melatonin on cell proliferation in a colon adenocarcinoma line

The effect of melatonin on inhibition of cell growth was studied in CT-26, a murine colon carcinoma-derived cell line. Cells growing in exponential phase were exposed to low (10(-7)-10(-10) M) and high doses (1, 2 and 3 x 10(-3) M) of melatonin during 24 h. Synthesis of DNA was measured by 5-bromo-2'-deoxyuridine incorporation. There was no effect at low doses, but a statistically significant correlation was found between the decrease in DNA synthesis and the dose of melatonin used (r = -0.52, P < 0.001). This implied the following percentages of inhibition: 1 mM, 22%; 2 mM, 25%; 3 mM, 47%. Potential cell membrane damage by high doses of melatonin was investigated by lactate dehydrogenase measurement and no significant levels were observed. Analysis with a single saturation technique showed no detectable oestradiol receptors in this cell type; therefore, we can assume that the effects occurring with the addition of melatonin were not mediated by modulation of this hormone on oestrogen receptors. The decreases in cell growth were attributed to a moderate, but significant antiproliferative action of melatonin on this non-hormone-dependent cell line.

In vitro effects of melatonin on cell proliferation in a colon adenocarcinoma line

The effect of melatonin on inhibition of cell growth was studied in CT-26, a murine colon carcinoma-derived cell line. Cells growing in exponential phase were exposed to low (10(-7)-10(-10) M) and high doses (1, 2 and 3 x 10(-3) M) of melatonin during 24 h. Synthesis of DNA was measured by 5-bromo-2'-deoxyuridine incorporation. There was no effect at low doses, but a statistically significant correlation was found between the decrease in DNA synthesis and the dose of melatonin used (r = -0.52, P < 0.001). This implied the following percentages of inhibition: 1 mM, 22%; 2 mM, 25%; 3 mM, 47%. Potential cell membrane damage by high doses of melatonin was investigated by lactate dehydrogenase measurement and no significant levels were observed. Analysis with a single saturation technique showed no detectable oestradiol receptors in this cell type; therefore, we can assume that the effects occurring with the addition of melatonin were not mediated by modulation of this hormone on oestrogen receptors. The decreases in cell growth were attributed to a moderate, but significant antiproliferative action of melatonin on this non-hormone-dependent cell line.

[Importance of the polyamines: review of the literature]

The polyamines, putrescine, spermidine and spermine, are low-molecular weight substances, synthesized in eucariot cells from their immediate precursor, ornithine. These nitrogen compounds are essential for growth. The organism's endogenous supply is obtained through the diet or by synthesis in the intestinal flora. The polyamines are found in fruits and vegetables, foods of animal origin (milk, eggs, fish, and meat) and fermented food products (cheese, beer, and sauerkraut). Being nitrogenated compounds, they are considered as "minor" components of the diet. Ornithine decarboxylase, a short-half life enzyme, is the key to polyamine biosynthesis. Cellular polyamines are found in free or conjugated forms, the latter made possible, above all, by the presence of positive charges in their molecules. Their particular structure facilitates interaction with anions and binding to nuclear and membrane structures, particularly phospholipids, proteins and DNA. The organism's requirements for these substances are elevated during phases of intense growth or increased demand; thus, the nutritional supply can be crucial during the evolution of processes that involve a high degree of loss combined with deficits in endogenous biosynthesis. Increased tissue and organ polyamine concentrations correlate with diseases of neoplastic origin. It has been hypothesized that polyamine inhibition could be a therapeutic mechanism for such conditions. The supply of polyamines in artificial nutrition has not been measured and there are few data on the effects of artificial nutrition on circulating levels or the usual sites of storage in the body.

Bibliographic information retrieval in the field of artificial nutrition

The enormous amount of data available for clinical and research purposes has made information searching a complex task. We have designed a study to determine which bibliographic databases provide appropriate information for the field of artificial nutrition. Of the 149 databases consulted in the preliminary search, 15 were found to contain an appreciable number of titles related to our field. As a general result, we found that MEDLINE had the largest number of titles but other databases oriented toward more specific topics contained references that were unique to them. The results show that an exhaustive search for any topic concerning artificial nutrition must be done on MEDLINE, EMBASE and Current Contents (75% productivity). These can be complemented with others according to their specialization in the subject to be treated. To obtain productivity over 75%, from five to seven databases must be consulted, according to the item under study.

Modification of organ protein synthesis after surgical stress by low energy diets with different lipid/glucose ratios

The aim of this work was to study the effects of low energy parenteral diets with different lipid/glucose ratios on rat liver and jejunal mucosa protein synthesis. The studied diets were: L0 (100% glucose, control diet), L25 (25% lipids: 75% glucose), L50 (50% lipids: 50% glucose) and L75 (75% lipids: 25 % glucose). All diets were isoenergetic and isonitrogenated, with a standard amino acid content. The diets were assayed in 93 rats with open femoral fracture immobilized by Kirschner pin insertion. The diets were administered for 4 days. On the fifth day, liver and jejunal mucosa protein synthesis were determined. Highest liver protein synthesis rates were obtained with the diet compositions: lipid/carbohydrate ratio: 25% lipids and 75% carbohydrates (expressed as energy ratio). A higher proportion of lipids significantly decreases liver protein synthesis (p <0.05). Jejunal mucosa protein synthesis followed the same pattern, with the same statistical differences.

Modification of organ protein synthesis after surgical stress by low energy diets with different supplements

We have studied the effects of hypocaloric diets with different supplements on liver and jejunal mucosa protein synthesis. The supplements assayed were medium chain triglycerides (diet MCT, with 50% carbohydrates: 25% long chain triglycerides (LCT): 25% medium chain triglycerides (MCT), standard amino acids), branched-chain amino acids (diet BCA, identical to control diet L50, with 15.3% of nitrogen replaced by branched-chain amino acids) and glutamine (diet GLN, identical to diet L50, with 15.3% of nitrogen replaced by glutamine). The control diet (L50) had 50% carbohydrates: 50% LCT and standard amino acids. The diets were assayed on 86 rats with femoral fracture immobilized by Kirschner pin insertion. Nutrition was administered for 4 days. On the fifth day, liver and jejunal mucosa protein synthesis was determined. A branched-chain amino acid supply in a proportion higher than 21.2% of amino acid nitrogen significantly decreased liver and jejunal mucosa protein synthesis, while the same amount of glutamine did not modify it. MCT had no effect on jejunal mucosa protein synthesis, while it was decreased significantly in the liver.

Evaluation of immune markers in asymptomatic AIDS patients receiving fish oil supplementation

The effects of oral fish oil (FO) supplementation (8 g/day, capsules) on nutritional status and selected immune markers (CD4/CD8 ratio, IL-1beta, erythrocyte MDA release, dehydroepiandrosterone sulfate [DHEA-S]) were studied in a homogeneous group of asymptomatic HIV-infected patients during 6 weeks. All subjects were classified clinically as A2 according to the CDC revised criteria (mean CD4 count 290 +/-123 cells/mm(3)) and were receiving zidovudine retroviral treatment. The calculated mean energy intake was 3437 +/- 372 Kcal/d, composed of 14% protein, 38% lipids and 48% carbohydrates, and was not modified during the study. The anthropometric parameters, and hematological and plasma biochemistry data showed non-significant changes after FO supplementation. Mean malonyldialdehyde (MDA) release before treatment was: unstimulated 71.5 +/- 37 and stimulated 350.9 +/- 79.8 nmol/g Hb. After FO supplementation (T(6)) MDA release showed unstimulated values of 96.1 +/- 62, and a significant increase after stimulation of 614.1 106.4 nmol/g Hb, which was, however, within the normal range. In the patient's samples, IL-1beta levels in the unstimulated blood culture showed a statistical increase with respect to the normal range before (T(0)) and after (T(6)) FO supplementation with a slight decrease after (mean 49.8 vs 40.9 pg/ml). The stimulated IL-1beta levels after treatment showed a statistically significant decrease that was maintained within the normal range (T(0): 797.7 vs T(6): 535.6 pg/ml). Taken collectively, these results suggest a tendency toward improvement in immune function.

Protein synthesis in specific tissues during sepsis

BACKGROUND

The hypothesis that fractional protein synthesis rates (Ks) are tissue-specific and bidirectional during sepsis was tested in an animal model.

MATERIAL AND METHODS

Ks in liver, triceps muscle, and diaphragm were measured in septic (n = 27) and control rats (n = 26). Sepsis was induced by a reproducible model established in our laboratory (intraperitoneal injection of sterile NaOH 0.75 N at 0.075 ml/100 g of body weight). Ks were measured using the flooding-dose method in tissue obtained from the diaphragm, liver, and from the triceps muscle.

RESULTS

In hepatic and diaphragmatic tissue, Ks were significantly higher in the septic animals (Ks: 112.2 +/- 8 and 5.4 +/- 1.9, respectively) than in control animals (Ks: 78.5 +/- 13 and 2.9 +/- 1.7, respectively). In the triceps, Ks were significantly lower in septic animals (Ks: 2.9 +/- 1.4) than in control animals (Ks: 5 +/- 1.8).

CONCLUSION

The results suggest that in septic animals the rate of protein synthesis is enhanced in tissues of priority, such as the liver, and varies in response to differences in muscle activity.

[Epidermal growth factor: is its application in nutrition feasible?]

Epidermal growth factor (EGF) was isolated in 1969 by Stanley Cohen in the submaxillary gland of the rat, and its structure was described by Taylor and Cohen in 1972. EGF is a 53-residue polypeptide, weighing 6372 daltons. It is synthesized in a precursor form, as Prepro-EGF, and is secreted into the saliva, intestine and urine. The degradation of EGF takes place primarily in the liver and secondarily in the digestive tract and kidney. EGF is a powerful mitogen, acting upon several types of cells. The epidermal growth factor receptor (EGF-R) is a 170,000 dalton glycoprotein which binds equally to EGF and transforming growth factor alpha (TGF-alpha), a constituent closely homologous to EGF. Presently, published studies concerning the use of EGF in parenteral and enteral nutrition are limited to experimental animals, in which clear effects on cellular proliferation have been observed. It has an important function in the digestive tract, protecting the gastric mucosa from stress and necrotizing agents. Thus, it might be useful in a new nutritional strategies, serving to combine the clearly beneficial effects provided by protein intake (non amino acid with those of the intestinal trophic and growth factors, in both parenteral and enteral nutrition.

Epidermal growth factor excretion in burned rats

Evidence for epidermal growth factor (EGF) involvement in the physiological response to burns was sought from urinary levels of EGF, urea and creatinine in male rats using a standardized thermal skin injury model (25 per cent body surface) and treated with fluid resuscitation. Postmortem, the skin lesions were studied by microscopy to guarantee the absence of inflammatory complications. Statistically significant differences were observed in body weight, urea and creatinine excretion when compared to the basal values. When EGF excretion results were evaluated as raw data (expressed as ng/mg of creatinine or ng/day) compared to basal levels, no statistically significant differences were observed. However, when the results were expressed as percentage increases with respect to the basal values, a statistically significant increase was found over the first 7 days postinjury (P = 0.029).

Effect of vitamin C and vitamin E analog on aged fibroblasts

Human dermal fibroblasts were cultured and aged in vitro. Survival of young and aged fibroblasts was determined in the presence and absence of different concentrations of two vitamins. Vit C at doses of 5, 12.5, 25 and 50 mumol/L and water-soluble Vit E (Trolox) at 1, 5, 10 and 50 mg/L, were added 30 minutes before oxidative stress, consisting of exposure to 5 mM hydrogen peroxide for 30 minutes. A non-radioactive cell proliferation cytotoxicity assay (MTT) was used to determine the protective effect of the vitamins studied. Vit C produced a clear cytoprotective effect on aged cells over the entire range of doses applied. The protection provided by Vit E, was less pronounced.

Effect of medium chain triglycerides (MCT) on jejunal mucosa mass and protein synthesis

The effects of medium chain triglycerides (MCT) on jejunal mucosa mass and protein synthesis were compared with results from previous experiments with rats fed by parenteral nutrition or enteral nutrition. Other published studies have also been analysed. Three experimental models were studied. In the traumatic model, production of a femoral fracture was followed by Kirschner pin insertion into the medullary canal of both fragments at reduction. (Forty ras were fed enteral nutrition and 93 were given parenteral nutrition.) A second model entailed resection under ether anaesthesia using the technique described by Higgins. (Fifty five rats were fed enteral nutrition and 28 with parenteral nutrition.) A third model entailed a terminolateral portocaval shunt under anaesthesia with pentobarbital. (Sixty nine rats were treated this way and then given enteral nutrition.) Proportions of medium chain/long chain triglycerides (LCT) were as follows: 0/100, 20/80, 40/60, 50/50, and 92/8 for enteral nutrition and 0/100, 30/70, 50/50, and 70/30 for parenteral nutrition. Faecal losses of alpha amino nitrogen, protein, total fats, and free fatty acids were analysed together with the quantitative intake, weight gain of the rats, jejunal mucosal mass, and protein synthesis in relation to the MCT proportion ingested or given by enteral nutrition or parenteral nutrition. From analysis of our results and those of others, several conclusions could be drawn. Firstly, the route of administration of MCT is extremely important and enterocytes might be considered one of the main target sites. Secondly, a high proportion of MCT (more than 80%) offers no advantage for jejunal mucosa and produces undesirable side effects. Thirdly, the effect of MCT on jejunal mucosal protein synthesis depends on the metabolic state. Finally, an increase in jejunal mucosal mass directly correlated with MCT concentrations, but no correlation was found between mass and protein synthesis. A positive correlation, however, between MCT proportion and enzyme activity (alkaline phosphatase and sucrase) in the brush border membrane was seen as well as a positive correlation with the concentration of phospholipids in the microvilli.

[The effect of sepsis on liver protein synthesis]

A study was made of the possible influence of sepsis on liver protein synthesis in septic and control rats, fed either parenterally (TPN) or with water and feed available "ad libitum". Liver protein synthesis was determined using the single massive dose method. In experiment I, the septic and control animals received TPN for twenty-four hours: in experiment II water and food was available to them "ad libitum". Twenty-four hours after the sepsis occurred, the animals were injected with a massive dose of 14C-labelled leucine, and slaughtered by decapitation. The septic animals with water and feed available "ad libitum" were fasted voluntarily without any intake. This group of fasted septic animals was the only one which lost weight. Liver protein synthesis increased in septic animals in comparison with the control animals, whether receiving TPN (112.2 +/- 8/78.5 +/- 13) or with "ad libitum" nutrition (97.2 +/- 15/60.8 +/- 8). The increased liver protein synthesis in the septic animals was modified (although with reduced significance) by parenteral nutrition (112.2 +/- 8/97.2 +/- 15). Our results suggest that sepsis increases liver protein synthesis, and that this protein synthesis may be enhanced by parenteral nutrition.

[Total abdominal irradiation. Choice of experimental dosage]

Radiation therapy induces morphological and functional changes in small intestine leading to nutrient malabsorption. The aim of this study was to determine the effect of total abdominal irradiation on body weight in rats. The study was performed in four groups of animals treated at increased levels of radiation: 400, 600, 800 and 1,000 cGy. The decrease in body weight observed was similar at the caloric and nitrogen intake and were more pronounced as the dose of radiation increased.

[Nutritional support in liver transplantation]

Given the malnutrition present in patients suffering from advanced hepatic illness, as well as the implications of this in the post-hepatic transplant period, a study was made of various biochemical parameters (prealbumin, retinol-bound protein, zinc, magnesium, cholesterol and amino acid pattern) as indicators of the nutritional condition of a series of 15 patients who underwent hepatic transplants and required total parenteral nutrition (TPN) during the first 10 post-transplant days. Before the transplants were carried out, all the patients studied showed a decrease in all evaluated parameters. Ten days after the transplant, and having been fed parenterally during this time, the different parameters corrected themselves, with the exception of cholesterol. TPN, administered with enrichment of branched amino acids by 35%, practically normalized the plasma amino acid pattern.

Effect of different MCT/LCT ratios on protein synthesis in injured rats fed parenterally

The effect of the lipidic composition of the diet on the proteic synthesis of the male Sprague-Dawley rats fed parenterally for four days has been studied. All animals received identical nitrogen and caloric intake, but the ratio of medium to long-chain triglycerides (MCT/LCT) varied: group 1, control (0/100); group 2 (30/70); group 3 (50/50) and group 4 (70/30). Hepatic and jejunal protein synthesis were determined with L-(1-14C)-leucine. In groups 1, 3 and 4 muscle protein synthesis was measured with L-(3,4-3H)-phenylalanine. In liver, there were no significant differences in the fractional synthesis rate among the groups. In jejunum, the control group showed a higher fractional synthesis rate with statistically significant differences among the groups. In muscle, group 3 presented the highest fractional synthesis rate with statistically significant differences (p less than 0.05).

Influence of fat emulsions in parenteral nutrition on visceral protein synthesis: study in hepatectomized rats

The aim of this study was to evaluate the effect of total parenteral nutrition (TPN) with 100% long-chain triglyceride (LCT) (group A) and 50/50% medium/long-chain triglyceride (MCT/LCT) (group B) fat emulsions on visceral protein synthesis in 70% hepatectomized rats. The rats were fed TPN continuously for 7 days posthepatectomy. Protein synthesis was measured in the liver and jejunal mucosa with the flooding dose method. All rats received the same caloric and nitrogen intake, without statistically significant differences. The only difference between the two groups was the proportion of MCT to LCT in the diets. Hepatic and jejunal mucosa protein synthesis were significantly higher in group B, fed 50/50% MCT/LCT. These results suggest that fat emulsions with 50/50% MCT/LCT significantly enhance visceral protein synthesis after partial hepatectomy.

[The use of immunologic parameters to assess the effectiveness of parenteral nutrition. Preliminary study]

Malnutrition leads to cellular and humoral immunological response disorders. A study protocol on malnourished patients has been designed in order to assess immune response mechanisms that may be altered due to malnutrition and may or may not recover once normal metabolic conditions have been restored prior to starting the patient on parenteral feeding and control. The immune response was assessed especially regarding immunoglobulin, lymphocyte subsets and mitogen response levels. It is important to know the different malnutrition-related immunologic disorders, disorders secondary to diseases that hinder correct oral feeding, and immunologic tests may be used to assess nutritional parameters. The malnourished patients included in this trial has to be free of any other immunologic or neoplastic disease, and not receive immune response suppression therapy. The trial patients showed lower total and relative CD3 and CD4 lymphocyte values at the onset of the study, although the former lymphocyte subset recuperated sooner at the expense of increasing CD8 lymphocytes, while CD4 lymphocytes still remained low after 15 days of parenteral nutrition. Immunoglobulin levels remained within normal limits. The mitogen response capacity, which was sensibly low at the beginning, recuperated in 50% of the cases treated with parenteral nutrition. This parameters may be used as an index to assess the nutritional status of these patients. The cases studies allowed us to conclude that there was a decrease in CD4 cells and mitogen response in malnourished patients. After 15 days of parenteral nutrition, the cells did not recuperate but their function measured in terms of phytohemagglutinin, was normal in 50% of the cases.

Influence of the qualitative caloric composition of enteral diets on liver protein synthesis in normal and operated rats

Protein synthesis L-(l-14C) leucine in liver was studied. Normal (n = 40) and operated (n = 40) Sprague-Dawley rats with an initial body weight of 161.18 +/- 12 g were divided into four groups (n = 10), respectively. Each group, subjected to the same conditions of temperature, light, noise and movement received a different commercial formula for human enteral nutrition and water for 8 days (normal rats) and six days (operated rats). All rats received the same caloric and protein intake per ml (l kcal; 6-7.10(-3) g protein), with no statistically significant differences among groups. The differences in diets were merely qualitative. The tolerance to all diets was similar, with rats attaining the expected weight. Losses of protein, alpha aminic nitrogen, total fat and non sterified fatty acid in faeces were negligible. In normal rats, different results in liver protein synthesis were obtained. No mass/synthesis rate correlation was found. Under these conditions it would appear that these results are due to the different diets used. In operated rats, a significantly different liver protein synthesis per gram of body weight was obtained, but not per gram of organ weight. These results suggest that the influence of the qualitative caloric intake, in the stress phase, is less than in the normal state.

Valuation of protein metabolism and albumin in patients submitted to peripheral parenteral nutrition (PPN)

A protein breakdown study was carried out in ten post-operative patients, 24 hours after operation and after five days of peripheral parenteral nutrition; five of these patients were in a good nutritive condition (group A) and five were suffering from malnutrition and were critically ill (group B). Results indicate that the administration of amino-acids achieved a decrease in the degree of protein breakdown in the two groups under study, and also it was observed that better use was made of the nitrogen administered, particularly by the liver when the nitrogenous supply is completed with carbohydrates such as glucose. The difference obtained in values between the oxidized leucine and the leucine administered suggests that there is an endogenous donor pool, and the differences existing between breakdown and leucine oxidation values indicate that in group A, nourished solely with amino-acids, breakdown is lesser and oxidation greater than in group B, nourished with amino-acids and glucose, which suggests that there is more stimulation to re-use the amino-acids in this group.

Intralipid and free plasmatic tryptophan in vitro

In an attempt to investigate the role of the lipidic emulsion Intralipid in the development of metabolic encephalopathy in a patient showing high free tryptophan levels, the relationship between lipidic emulsion and free tryptophan was examined in in vitro experiments. The addition of intralipid to normal serum produces an immediate increase in non-esterified fatty acids and a parallel rise in free tryptophan. Moreover, when serum with intralipid is incubated at 37 degrees C, the lipases release new non-esterified fatty acids and the free tryptophan increases proportionally. The non-esterified fatty acid content of intralipid was found to be 12 +/- 2 mEq X 1(-1). An inverse correlation was seen between free tryptophan and different serum albumin concentrations. It is concluded that intralipid causes an increase in free tryptophan levels. It is known that in vivo free tryptophan modulates 5-hydroxytryptamine synthesis and thus may be considered a possible causal agent for encephalopathy.