Aflatoxins are natural scavengers of reactive oxygen species

The role of aflatoxins (AFs) in the biology of producing strains, Aspergillus sect. Flavi, is still a matter of debate. Over recent years, research has pointed to how environmental factors altering the redox balance in the fungal cell can switch on the synthesis of AF. Notably, it has been known for decades that oxidants promote AF synthesis. More recent evidence has indicated that AF synthesis is controlled at the transcriptional level: reactive species that accumulate in fungal cells in the stationary growth phase modulate the expression of aflR, the main regulator of AF synthesis—through the oxidative stress related transcription factor AP-1. Thus, AFs are largely synthesized and secreted when (i) the fungus has exploited most nutritional resources; (ii) the hyphal density is high; and (iii) reactive species are abundant in the environment. In this study, we show that AFs efficiently scavenge peroxides and extend the lifespan of E. coli grown under oxidative stress conditions. We hypothesize a novel role for AF as an antioxidant and suggest its biological purpose is to extend the lifespan of AFs-producing strains of Aspergillus sect. Flavi under highly oxidizing conditions such as when substrate resources are depleted, or within a host.

Economic evaluation of the randomized European Achalasia trial comparing pneumodilation with Laparoscopic Heller myotomy

BACKGROUND

A recent multicenter randomized trial in achalasia patients has shown that pneumatic dilation resulted in equivalent relief of symptoms compared to laparoscopic Heller myotomy. Additionally, the cost of each treatment should be also taken in consideration. Therefore, the aim of the present study was to perform an economic analysis of the European achalasia trial.

METHODS

Patients with newly diagnosed achalasia were enrolled from to 2003 to 2008 in 14 centers in five European countries and were randomly assigned to either pneumatic dilation (PD) or laparoscopic Heller (LHM). The economic analysis was performed in the three centers in three different countries where most patients were enrolled (Amsterdam [NL], Leuven, [B] and Padova [I]) and then applied to all patients included in the study. The total raw costs of the two treatments per patient include the initial costs, the costs of complications, and the costs of retreatments.

RESULTS

Two hundred and one patients, 107 (57 males and 50 females, mean age 46 CI: 43-49 years) were randomized to LHM and 94 (59 males and 34 females, mean age 46 CI 43-50 years) to PD. The total cost of PD per patient was quite comparable in the three different centers; €3397 in Padova, €3259 in Amsterdam and €3792 in Leuven. For LHM, the total costs per patient were highest in Amsterdam: €4488 in Padova, €6720 in Amsterdam, and €5856 in Leuven.

CONCLUSION

In conclusion, the strategy of treating achalasia starting with PD appears the most economic approach, independent of the health system.

Long-term outcome and risk of oesophageal cancer after surgery for achalasia

BACKGROUND

Few studies have reported very long-term results after surgery for oesophageal achalasia. The aim of the present study was to assess long-term subjective outcomes after cardiomyotomy and partial fundoplication, focusing specifically on the risk of oesophageal cancer.

METHODS

Clinical and demographic information from 228 consecutive patients who had surgery between 1980 and 1992 was extracted from hospital files. Survival status and dates of death were obtained from census offices. Causes of death were obtained from public registries and compared with those of the general population. Symptoms were assessed by means of a questionnaire and endoscopy results were scrutinized.

RESULTS

Among 226 patients who could be traced, 182 of 184 survivors were contacted and the cause of death established for 41 of 42 patients. At a median follow-up of 18.3 years, almost 90 per cent of patients were satisfied with the treatment. Four had developed squamous cell oesophageal carcinoma 2, 8, 13 and 18 years after surgery, one of whom was still alive. The standardized mortality ratio for oesophageal carcinoma was significantly higher than expected in men.

CONCLUSION

Cardiomyotomy and partial fundoplication is an excellent long-term treatment for achalasia. Men with achalasia have an increased risk of developing oesophageal cancer.

Biosensors for determination of total and natural antioxidant capacity of red and white wines: comparison with other spectrophotometric and fluorimetric methods

Research was carried out to experimentally evaluate the antioxidant capacity of several red and white wines using a superoxide dismutase (SOD) biosensor recently developed by the present authors. Measurements were performed by comparing the biosensor response to increasing concentration of the superoxide radical produced in solution by the xanthine/xanthine oxidase system, both in the presence and absence of the test sample.The results were compared with those of two traditional spectrophotometric methods and of a spectrofluorimetric method described in literature.Lastly, also the polyphenol, sulfite and ascorbic acid contents of the different wine samples examined were measured using a tyrosinase biosensor, a sulfite oxidase biosensor and an ascorbate oxidase biosensor, respectively.

Physico-chemical characteristics of olives and olive oil from two mono-cultivars during various ripening phases

The aim of this study was to find a correlation between the chemical and physical parameters in the pulp of the olive, in order to identify the optimum period during the 1998 harvesting period. For this reason various parameters have been monitored: the amount of oil in the pulp during the ripening phase obtained by solvent extraction with n-hexane, the acidity, the peroxide value, the composition of fatty acids and the saturated/unsaturated fatty acid ratio, the composition of the unsaponifiable fraction, the antioxidant capacity, the percentage of oil and the puncture test in two local Croatian olive cultivars. The chemical parameters change during the ripening, in order to control the oxidative changes of the cellular homeostasis of the whole lipophilic fraction that needs a stronger safeguard of the double bonds against the oxidative stress. The modification of the physical characteristics, observed with the puncture test, is related to the chemical changes which occur in the olive during the ripening period and the monitoring of these physical and chemical parameters can help to increase nutritional quality (as antioxidant capacity) and allow for an acceptable amount of oil.

Keratinophilic fungi in the antarctic environment

Results of a study on the diffusion of keratinophilic fungi in an Antarctic environment are given. Nine soil samples collected from as many sites along the coast of Ross Sea, and six dust samples inside the Italian scientific base were examined by direct inoculation and hair baiting methods for soil samples and plate dilution method for dust samples. As regards the variety of species isolated and the counting of the numbers of colonies, plate dilution method proved to be very effective. Aspergillus spp., Cladosporium sp., Dematiaceae, Fusarium sp., Geomyces pannorum v. pannorum, G. pannorum v. vinaceus, Mycelia sterilia, Penicillium spp. were isolated from soil. From the dust the following moulds were isolated: Aphanoascus fulvescens, Aspergillus sp., Beauveria sp., Chrysosporium carmichaelii, Dematiaceae, Geomyces pannorum v. pannorum, G. pannorum v. vinaceus, Malbranchea gypsea, Mycelia sterilia, Nectria inventa, Penicillium spp., Scopulariopsis brevicaulis, Scopulariopsis sp. and Trichophyton mentagrophytes. The presence of four colonies of Trichophyton mentagrophytes is emphasized and correlated with the anthropization process.

Sebacic acid binding to human plasma albumin

Sebacic (decanedioic) acid is a dicarboxylic acid proposed recently as an alternative energy substrate in total parenteral nutrition. In this paper, binding of sebacic acid to defatted human plasma albumin, also in the presence of decanoic acid, was studied by means of equilibrium dialysis. In addition, the binding of sebacic acid in human serum was investigated. Binding to defatted albumin was analysed by a model with two independent classes of sites with different affinity constants. The fitting procedure took into account some of the measurement errors that are likely to affect the equilibrium dialysis technique. We found for sebacic acid one binding site with affinity constant 3.69 x 10(4) M-1 and four to five sites with affinity constant 7.14 x 10(2) M-1. Association constants for decanoic acid are 3-4-fold larger than those of sebacic acid. Data of binding of sebacic acid in human serum suggested that only three to five of the low affinity sites are available for binding. When disodium sebacate is administered i.v. for total parenteral nutrition, a substantial fraction of sebacic anions is likely to be bound in serum.

Metabolic effects and disposition of sebacate, an alternate dicarboxylic fuel substrate

Disodium sebacate is a 10-carbon-atom dicarboxylic acid, proposed as substrate for parenteral nutrition. We investigated its pharmacokinetic profile and thermogenic effect during a short-time infusion (5 h at 10 g/h) in 7 male volunteers. Sebacate in serum and urine was measured by high-performance liquid chromatography. A single-compartment model with two linear elimination routes was fitted. Metabolic measurements (VO2, VCO2, respiratory quotient, metabolic rate) were continuously performed for 8 h (5 h during and 3 h after the infusion) by a canopy indirect calorimeter. The apparent volume of distribution of sebacate was 8.39 +/- 0.69 liters, and the plasma fractional removal rate constant was 0.0086 +/- 0.00077 min-1. The average half-life and plasma clearance were 80.6 min and 72 ml/min, respectively. The increase in metabolic rate, the decrease in respiratory quotient and the changes in ketone body, glucagon and insulin levels during the infusion were not significant. 24-hour catecholamine excretion was within normal limits. Calories administered by sebacate seem to be available for utilization without relevant metabolic side effects.

Use of even-numbered carbon atom dicarboxylic salts in parenteral nutrition as fuel substrate

Sebacic acid (C10), a saturated, straight-chain dicarboxylic acid with 10 carbon atoms in disodic salt form, was given intravenously to two groups of healthy male volunteers in order to evaluate its possible use in total parenteral nutrition. The first group, composed of six subjects, received 1000 mg of sebacate as a bolus; six other subjects (second group) received 10 g of sebacate dissolved in 500 mL of double-distilled water at an infusion rate of 3.33 g/h over 3 hours. The serum sebacate data for each subject were analyzed by computer, using biexponential fit corresponding to a 2-compartment open model. The distribution half-life (t1/2) was 0.34 +/- 0.06 hour and the elimination phase was rather rapid (Ke = 2.10 +/- 0.38/h); the volume of the central compartment was 2.79 +/- 0.54 L and the volume of tissue compartment 3.72 +/- 0.14 L. These data showed a good tissue fixation of sebacate. The plasma clearance was evaluated to be 5.96 +/- 2.19 L/h and the renal clearance was 19.22 +/- 10.69 L/h, indicating that a tubular secretion of C10 takes place. The serum concentration of sebacate raised to the maximal value at the end of the infusion (180 minutes), corresponded to 480.50 +/- 43.02 micrograms/mL. Respiratory and metabolic parameters were evaluated by indirect calorimetry from the beginning of the infusion for 210 minutes. The O2 consumption (VO2 mL/min per square meter) remained essentially unchanged throughout the experiment (from 154.3 +/- 28.3 at 0 to 155.3 +/- 39.5 at time 180 minutes).(ABSTRACT TRUNCATED AT 250 WORDS)

Tissue uptake and oxidation of disodium sebacate in man

In order to better ascertain its possible use as an alternative fuel substrate in total parenteral nutrition, sebacate (Sb) metabolism was studied in seven overnight-fasting healthy male volunteers, who received a constant iv infusion (99 mmoles over 8 hours) of disodium sebacate. Sb oxidation rate was determined using an isotopic sebacate (disodic salt of (1-10)14C-sebacic acid) infusion (100 mu Ci from the fourth to the eighth hour of the cold sebacate infusion). Blood samples were collected during and after sebacate infusion at intervals of 30 minutes and Sb serum concentrations were determined by high performance liquid chromatography. Excreted radioactivity (mu Ci/min) was measured by bubbling the expired air into an apparatus containing 3 mEq hyamine to trap CO2 from a 20-L Douglas-bag. CO2 production and O2 consumption were measured before and at 4 and 8 hours after starting the infusion. Twenty-four hour nitrogen excretion with urine was obtained. The RQ and the percent of calories derived from lipid oxidation were calculated by indirect calorimetry. The Sb serum level at the plateau phase was (mean +/- SD) 4.54 +/- 0.71 mumole/mL, the overall rate of tissue uptake was 180.89 +/- 4.50 mumole/min, and the percent oxidation was 6.14 +/- 0.44%. At the end of Sb infusion the RQ dropped to 0.839 +/- 0.043, the percent of calories due to sebacate oxidation was 1.59 +/- 0.52%, and the calories derived from lipids increased to 37.77 +/- 12.90%. These data show that a definite amount of the sebacate infused is oxidized in human tissues.

Pharmacokinetic analysis of azelaic acid disodium salt. A proposed substrate for total parenteral nutrition

Azelaic acid was the first dicarboxylic acid proposed as an alternative energy substrate in total parenteral nutrition. In this study, the pharmacokinetics of azelaic acid were investigated in 12 healthy volunteers, 7 receiving a constant infusion (10g over 90 min) and 5 a bolus dose (1g). The 24h urinary excretion and plasma concentration in blood samples taken at regular intervals were assayed by gas-liquid chromatography. Experimental data were analysed by a 2-compartment nonlinear model that describes both tubular secretion and cellular uptake in Michaelis-Menten terms. A high value of urinary excretion (mean 76.9% of infused dose) and a mean clearance of 8.42 L/h were found, suggesting the presence of tubular secretion. Estimating the population mean of the pharmacokinetic model parameters gave a maximal cellular uptake of 0.657 g/h. The model predicts that 90% of the maximal uptake should be reached in the plateau phase of a constant infusion of 2.2 g/h. The presence of extensive and rapid losses through urinary excretion, and the low estimated value of the maximal cellular uptake, indicate that azelaic acid is not suitable as an energy substrate for total parenteral nutrition.

Preliminary studies of a dicarboxylic acid as an energy substrate in man

Azelaic acid (Az), a straight saturated chain nine carbon dicarboxylic acid, was administered in saline form to six healthy male volunteers by iv route. Serum levels of Az and urinary amounts of both azelaic and pimelic (C7) acids were measured by an improved gas liquid chromatographic method. Stoichiometric analysis of Az metabolism was compared with that of glucose and palmitic acid. The respiratory quotient (RQ) as well as the ATP/CO2 ratio of Az were quite similar to that of palmitic acid. Therefore, Az oxidation is associated with a low cost of ATP synthesis in terms of carbon dioxide production. At the infusion rate used (7.5 g/hr) more than 50% of the administered dose was excreted in the urine. However, the remaining portion was cleared from the plasma in 200 min suggesting an uptake by body tissues which was also confirmed by indirect calorimetric analysis.

Free fatty acids: a stimulus for mucin hypersecretion in cholesterol gallstone biles

The concentration of free fatty acids, phosphatidylcholine and lysophosphatidylcholine, and the fatty acid composition as well as the levels of the mucins, analyzed by an improved GLC method, were examined in ten biles from patients with cholesterol gallstones (pathological biles) and in ten control biles. In pathological biles the amounts of free fatty acids and phosphatidylcholine, were significantly higher (8.99 +/- 1.09) vs. 2.75 +/- 0.62 micrograms/mg) and lower (6.62 +/- 0.71 vs. 21.91 +/- 3.86 micrograms/mg), respectively, than in control biles, indicating that a relationship exists between the two lipid fractions. Lysophosphatidylcholine concentrations remained unchanged in the two groups (1.02 +/- 0.55 micrograms/mg in pathological biles vs. 1.32 +/- 0.57 micrograms/mg in control biles). The increased levels of free fatty acids were directly correlated (r = 0.73, P less than 0.05) with biliary hypersecretion of mucus glycoproteins. Acetylglucosamine and acetylgalactosamine were significantly higher in pathological biles than in control biles (1.91 +/- 0.67 vs. 0.60 +/- 0.13 microgram/mg). The nucleating potency of the increased amounts of mucins, coupled with lowered levels of phosphatidylcholine, might play a very important role in stone formation and precipitation.

Stimulation of aflatoxin biosynthesis by lipophilic epoxides

Epoxy fatty acids added to the culture media either with the inoculum or at the end of exponential growth phase stimulated aflatoxin production by toxigenic strains of Aspergillus flavus and Aspergillus parasiticus. This effect did not appear when the unsaturated fatty acids used for the synthesis of the epoxides and the polyhydroxyacids (which can be considered to be derived from the opening of the oxirane ring) replaced the epoxides in the culture media. No significant differences were detected in the lipid fractions (diglycerides, sterols, triglycerides, free fatty acids, sterol esters) extracted from the mycelia grown in the presence of any of the fatty acid derivates.