Implications of full-scale implementation of an anammox-based process as post-treatment of a municipal anaerobic sludge digester operated with co-digestion.

The feasibility of treating the supernatant of a municipal sludge digester supplemented with co-substrates by means of an anammox-based process (ELAN(®)) was tested in Guillarei (NW of Spain). Ammonia concentration measured in the supernatant of the sludge digester varied in the range 800-1,500 g N/m(3) due to the fact that the sludge produced in the plant was co-digested with wastes coming from surrounding food industries. Treating this supernatant in the ELAN(®) reactor, nitrogen removal rates up to 1.1 kg N/(m(3) d) were reached in experiments run in a pilot plant reactor operated in batch mode. No nitrite oxidation was registered after several months of operation despite the average dissolved oxygen (DO) concentrations being 1.5 g O2/m(3) and the temperature reaching values as low as 18 °C. By keeping the DO set point at 1-2 g O2/m(3) and tuning the hydraulic retention time, the stability of the process was guaranteed and the presence of co-substrates in the anaerobic digester did not affect negatively the operation of the autotrophic nitrogen removal process. Due to the success of the pilot plant experiment, an upscale of the process to full scale is proposed. Mass balances applied to Guillarei wastewater treatment plant revealed that in the main stream line the average denitrification rate calculated with the data of year 2011 was 226 kg N/d. Since the nitrogen removal efficiency is limited by the amount of readily biodegradable organic matter available to carry out denitrification in the water line, the implementation of an anammox-based process to treat the supernatant seems the best option to improve the effluent quality in terms of nitrogen content. The nitrogen removal rate in the sludge line would be 30 times higher than the one in the water line. The implementation of the process would improve the energetic balance and the nitrogen removal performance of the plant.

Estudio experimental sobre los efectos de la quercetina en la disfunción orgánica y cognitiva originada por radiación ionizante / Experimental study about the effects of quercetin on the organic and cognitive dysfunction induced by ionizing radiation

Objetivo: Comprobar el efecto de la incorporación de quercetina por vía oral sobre las alteraciones comportamentales, bioquímicas e histológicas de una dosis subletal de rayos X en la rata. Material y método: Se irradiaron a cuerpo entero con 6 Gy de rayos X ratas Wistar macho suplementadas o no con 50 mg/kg de quercetina. Se obtuvieron imágenes por RM a los dos, siete, 15 y 30 días tras la irradiación, y se observó el comportamiento exploratorio mediante open field antes y después de la irradiación. Los animales se sacrificaron a los siete y 30 días, obteniéndose muestras de sangre, cerebro, médula espinal y médula ósea. Resultados: Se observó un fuerte descenso en el recuento eritrocitario, leucocitario y plaquetario a los siete días, recuperándose a los 30 días los recuentos leucocitario y plaquetario, sin efecto de la quercetina. La RM mostraba focos de microsangrado consistentes con los hallazgos histológicos de infiltración celular por alteraciones neurovasculares, más evidentes en animales no suplementados. La quercetina atenuó estas alteraciones y revertió la disminución de la actividad exploratoria ocasionada por la irradiación. Conclusiones: El uso preventivo de quercetina podría mejorar los síntomas comportamentales y disminuir el daño tisular a corto plazo tras sesiones de radioterapia (AU)

Objective: To assess the effect of oral quercetin supplementation on the behavioral, biochemical, and histological alterations by a sublethal X-ray dose in rats. Materials and method: Male Wistar rats, supplemented with 50 mg/kg quercetin or solvent, were whole-body irradiated with 6 Gy X-rays. MRI was obtained at 2, 7, 15, and 30 days post-irradiation. Open field exploratory behavior was observed before and after irradiation. Rats were sacrificed at 7 and 30 days post-irradiation, and blood, brain, spinal cord, and bone marrow samples were obtained. Results: Red cell, white cell, and platelet counts strongly decreased at 7 days post-irradiation. White cell and platelet counts recovered at 30 days post-irradiation, with no effect by quercetin. MRI shows focal microbleeds consistent with the histological findings of cell infiltration by neurovascular alterations, more evident in non-supplemented rats. Quercetin improved these changes and reverted the decrease in exploratory activity due to Xirradiation. Conclusions: Preventive use of quercetin could improve early behavioral symptoms and decrease tissue damage appearing shortly after radiotherapy (AU)

Evaluation of the potential protective effects of ad libitum black grape juice against liver oxidative damage in whole-body acute X-irradiated rats.

AIMS: The aim of this study was to evaluate the potential protective effects of ad libitum black grape (Vitis labrusca) juice against liver oxidative damage in whole-body acute X-irradiated rats. MAIN METHODS: Animals were fed ad libitum and drank voluntarily black grape juice or placebo (isocaloric glucose and fructose solution) for 6 days before and 15 days following a 6 Gy X-irradiation from a 200 kV machine. KEY FINDINGS: Irradiated animals receiving placebo showed a significant increase in the concentration of thiobarbituric acid-reactive substances (TBARS), a marker of lipid peroxidation, as well as a significant decrease in both Cu/Zn superoxide dismutase (Cu/ZnSOD) and glutathione peroxidase (GPx) activity and reduced glutathione concentration (GSH). Black grape juice supplementation resulted in a reversal of lipid peroxidation, Cu/ZnSOD activity, and GSH concentration, towards values not significantly differing from those in non-irradiated, placebo-supplemented rats. Poly(ADP-ribose) polymerase (PARP-1) and Cu/ZnSOD changes in protein expression were observed for irradiated rats. No change in p53 expression or DNA fragmentation was found. SIGNIFICANCE: Ad libitum black grape juice intake is able to restore the liver primary antioxidant system against adverse effects due to whole-body acute X-irradiation in rats after 15 days post-irradiation. The results support using antioxidant supplements as a preventive tool against radiation-induced harm.

Effect of melatonin supplementation on food and water intake in streptozotocin-diabetic and non-diabetic male Wistar rats.

The effect of orally supplemented melatonin (MT) at 1 mg/kg bw for 4 weeks on feeding behavior of non-diabetic and diabetic male Wistar rats has been studied by computerized meal pattern analysis. Exogenous MT has a satiating effect in non-diabetic rats, but not in diabetic animals. The changes in feeding behavior induced by MT in non-diabetic animals are related to changes in meal frequency, size and duration leading to lower total food intake during the scotophase. MT administration to diabetic rats resulted in lower drinking time and higher faecal output, without further behavioral effects. We conclude that the notorious metabolic changes occurring in the streptozotocin-diabetic rat can overcome most of the underlying effects of MT supplementation. The possible MT usage for therapeutical purposes could benefit from the lack of behavioral alterations in diabetic animals.

Radiomodifying effect of organic grape juice supplementation on hematological parameters and organ weight in whole-body X-irradiation in rats.

The aim of this study is testing black grape juice as a radiomodifier against whole body X-irradiation using an animal model. Sixteen male Wistar rats were divided into four groups where two were irradiated by X-rays from a 200 kV machine specially designed to biological samples. Animals were fed ad libitum and drank voluntarily 2-10 ml a day of grape juice or placebo (isocaloric glucose and fructose solution) for one week before and two weeks after 6 Gy X-irradiation when they were sacrificed. Results have shown a significant liver weight loss in irradiated placebo group only while grape juice one has presented no losses. Hematological analysis showed typical abnormalities for ionizing radiation exposure, including early leucopenia and anemia. The intake of grape juice induced an increase in granulocyte percent count.

[Experimental models on hemorragic shock]. / Modelos experimentales sobre shock hemorrágico.

This review addresses the pathophysiology and treatment of hemorrhagic shock, a condition produced by rapid and significant loss of intravascular volume. Hemorrhagic shock may lead sequentially to hemodynamic instability, decreases in oxygen delivery, decreased tissue perfusion and cellular hypoxia. Multiple organ failure, a systemic inflammatory process that leads to dysfunction of different vital organs, is a frequent complication after hemorrhagic shock and accounts for a high incidence of mortality. The pathogenesis of organ injury secondary to hypovolemic insults is still not completely understood, but both experimental studies and clinical observations indicate that macrophages are activated by translocated endotoxin-bacteria and ischemia/reperfusion. Activated Kupffer cells release pathologically active substances such as inflammatory cytokines, reactive oxygen species, and nitric oxide, all of which may participate in the mechanisms of hemorrhagic shock. Moreover, increased free radical production during hemorrhagic shock and resuscitation gives place to an increase in oxidative stress that would contribute to the organ damage. In the last few years, a number of experiments have been performed in an attempt to understand the pathophysiology and treatment of hemorrhagic shock. Different studies have shown positive effects on hemorrhagic shock treatment by antioxidant, amino acid, and lipid administration.

Appetite depression in sheep experimentally infected with Fasciola hepatica L.

The purpose of this study was to determine the effects of experimental fasciolosis at various stages of development on the daily food intake of sheep. Five male Churra sheep, 4 months of age, were infected orally with 300 Fasciola hepatica metacercariae over a 30 day period. There was a significant increase in serum glutamate dehydrogenase (GLDH) activity from 40 days post-infection and in aspartate aminotransferase (AST) activity from 60 days post-infection. Both enzyme activities reached maximum levels in the serum of infected animals at 80 days and then progressively decreased. Serum gamma-glutamyltransferase (GGT) activity was significantly increased from 80 to 120 days post-infection. Glycaemia was significantly decreased from 60 days post-infection. The average daily food intake was shown to steadily decrease until approximately 100 days. The coincidence of decreased food intake with the period of significant increase, both in AST and GLDH activities, indicated that damage caused around the time of migration of immature flukes through the liver parenchyma may be involved in appetite depression.

Influence of ethanol on gastric absorption and metabolism of albendazole and mebendazole.

The effect of ethanol administration on gastric absorption in rats of two benzimidazole derivatives has been studied. The ethanol administration was carried out as both acute (5%, 10% and 15% w/v of ethanol in the perfusion solution), and chronic (15, 30 and 120 days) forms. Two benzimidazole derivatives were used: albendazole (ABZ) and mebendazole (MBZ). The administration of ethanol did not affect the kinetic mechanism of the absorption process (simple diffusion) but the absorption rate decreased in all treatments except in 5% acute ethanol, presumably due to the improved solubility of the drugs. Plasma, bile and liver levels after gastric perfusion suggest a possible interference of ethanol metabolism with drug hepatic metabolism.

Abdominal chemo- and mechanosensitivity in ruminants and its role in the control of food intake.

Ruminant animals have evolved a large and complex set of stomachs which allow fermentation of fibrous food by symbiotic micro-organisms. These stomachs are well innervated and generate signals which are thought to be important in the control of voluntary food intake. Tension receptors in the muscular wall of the rumen and reticulum are slowly adapting and provide a measure of distension while epithelial receptors are rapidly adapting and provide information on the fibrousness of the digesta; they are involved in the control of stomach motility and voluntary food intake in order to prevent excessive distension. The epithelial receptors are also sensitive to the chemical nature of the digesta, particularly acidity. There are mechano- and chemoreceptors in the abomasum (true stomach) and duodenum and chemoreceptors in the liver, all of which have been implicated in the control of intake. It is relatively easy to prepare and maintain ruminants with a rumen fistula and many studies have shown the effects of such manipulations as distension of balloons in the rumen on voluntary intake. With fibrous, slowly digested feeds intake is primarily limited by rumen distension. With more rapidly digested feeds, however, the products of digestion play an important role in controlling intake. Short-chain fatty acids are the main products of fermentation and infusion of their salts into the rumen depresses food intake to a much greater extent than infusion into the general circulation. Acetate or propionate given into the rumen are more effective, mole for mole, than butyrate but must be given at rates exceeding the natural rate of production in order to have a significant effect. It has been suggested that much of the effect of sodium acetate is via the increase in the osmolality of rumen fluid but there is considerable uncertainty as to the physiological significance of osmotic effects, especially when animals have free access to water and can prevent excessive increases in tonicity by increasing their water intake. Other constituents of rumen fluid have been implicated in the control of food intake, particularly lactic acid and nitrogenous compounds, especially as these can be found in fermented feeds such as silage. The omasum controls the flow of digesta to the abomasum; it is therefore well placed to control rumen fill and thus intake but there has been little study in this area and this is also true for the abomasum.(ABSTRACT TRUNCATED AT 400 WORDS)

Comparative study on gastric absorption of albendazole and mebendazole in rats.

1. A study was carried out to determine the kinetics of the gastric absorption of two wide spectrum benzimidazole anthelmintics, albendazole and mebendazole. 2. The method used was gastric recirculation of solutions containing the drugs in concentrations ranging from 0.5 to 100 mM. 3. The results obtained showed that absorption corresponds to first order kinetics, with diffusion constants of 0.0087 min-1 for albendazole and 0.0077 min-1 for mebendazole. 4. Blood levels of the drugs for the whole range of concentrations were always higher in the case of albendazole.

Kinetic mechanism for the intestinal absorption of ofloxacin.

The absorptive behaviour of ofloxacin, a quinolone antibacterial agent, was studied following recirculation in small intestine of both male and female rats, at initial doses ranging from 0.125 to 5 mg mL-1. A saturable Michaelis-Menten process is suggested to explain the intestinal absorption. No significant differences were found in the absorption parameters per metabolic weight unit.

Prediction of the effect of ofloxacine on intestinal absorption: effect of the body weight and substrate concentration.

1. The effect of body weight and initial concentration on the rat small intestinal absorption of DL-8280 (ofloxacine) is studied using a recirculating perfusion technique and an improved HPLC method. 2. A prediction equation is developed under statistical and physiological considerations which correlates both factors with the intestinal absorption rate parameter Kapp.

Intestinal absorption of acidic beta-lactam antibiotics: contribution of ionized and un-ionized forms.

The effect of the pH of dissolutions of weakly acidic beta-lactam antibiotics on their intestinal absorption has been studied by quantification of the contribution of the ionized and un-ionized antibiotic forms to the whole absorptive process. In vivo recirculation in both sexes of adult Wistar rats was performed with buffer solutions at different pH values and samples were analyzed by high-performance liquid chromatography (HPLC).

A BASIC program for determination of numerical density of cytoplasmic compartments--I. Analysis of spherical particles.

The mean diameter of spherical-like particles is determined by a BASIC program taking into account how the sampled diameters are distributed. In this way the numerical density of the cytoplasmic compartments is obtained. Also calculations considering Holmes' effect are provided.

A BASIC program for determination of numerical density of cytoplasmic compartments--II. Analysis of ellipsoids and cylindrical particles.

A BASIC program is presented to obtain the numerical density, shape coefficient (beta) and kappa factor for the size distribution of a series of diameters measured from E.M. micrographs. Also its minimal sample size can be estimated.

Stereological parameters from the analysis of the cell micrographs either by manual point-counting methods or by using a semi-automatic system: a BASIC program for ZX-Spectrum personal computer.

A BASIC program is presented which calculates stereological parameters from the data obtained by the analysis of cell micrographs, either by manual point-counting or semi-automatic analysis methods.

Computer programs to obtain HPLC parameters of beta-lactam antibiotics.

Listings of BASIC and TI-59 programs are included to obtain the HPLC retention factors for beta-lactam antibiotics at given antibiotic pK's, pH, and capacity factor values, which are useful in considering the different chromatographic behaviour of antibiotics as the pH varies.

Isolation and kinetic properties of pyruvate kinase activated by fructose-1,6-biphosphate from Salmonella typhimurium LT-2.I.

Pyruvate kinase, activated by fructose-1,6-biphosphate from Salmonella typhimurium LT-2, has been isolated and purified to homogeneity. The enzyme, similar to that from Escherichia coli, is a tetramer with an approximate molecular weight of 240,000. The native enzyme shows optimum pH 6.8 (T = 30 degrees C). The enzymatic reaction does not require K+ ions; while Mg2+ or Mn2+ are essential for its activity. The non-activated enzyme shows sigmoid kinetics to phosphoenolpyruvate with a Hill coefficient of 2.73; the activated enzyme becomes michaelian with KSADP y KSPEP 0.25 and 0.08 mM, respectively. Both substrates excess and ATP cause enzyme inhibition. In agreement with the experimental results a steady-state random-ordered hybrid Bi-Bi mechanism with two dead-end complexes is proposed.