[Ingestion of antioxidants and polyamines in patients with severe burns]. / Ingesta de antioxidantes y poliaminas en pacientes con quemaduras graves.

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.

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.

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.

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.

[Polyamines in the gastrointestinal tract]. / Poliaminas en el tracto gastrointestinal.

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.

[Importance of the polyamines: review of the literature]. / Importancia de las poliaminas: revisión de la literatura.

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.