Is it possible to increase bioavailability but not environmental risk of PAHs in bioremediation?

The current poor predictability of end points associated with the bioremediation of polycyclic aromatic hydrocarbons (PAHs) is a large limitation when evaluating its viability for treating contaminated soils and sediments. However, we have seen a wide range of innovations in recent years, such as an the improved use of surfactants, the chemotactic mobilization of bacterial inoculants, the selective biostimulation at pollutant interfaces, rhizoremediation and electrobioremediation, which increase the bioavailability of PAHs but do not necessarily increase the risk to the environment. The integration of these strategies into practical remediation protocols would be beneficial to the bioremediation industry, as well as improve the quality of the environment.

Effect of interface fertilization on biodegradation of polycyclic aromatic hydrocarbons present in nonaqueous-phase liquids.

The main goal of this study was to use an oleophilic biostimulant (S-200) to target possible nutritional limitations for biodegradation of polycyclic aromatic hydrocarbons (PAHs) at the interface between nonaqueous-phase liquids (NAPLs) and the water phase. Biodegradation of PAHs present in fuel-containing NAPLs was slow and followed zero-order kinetics, indicating bioavailability restrictions. The biostimulant enhanced the biodegradation, producing logistic (S-shaped) kinetics and 10-fold increases in the rate of mineralization of phenanthrene, fluoranthene, and pyrene. Chemical analysis of residual fuel oil also evidenced an enhanced biodegradation of the alkyl-PAHs and n-alkanes. The enhancement was not the result of an increase in the rate of partitioning of PAHs into the aqueous phase, nor was it caused by the compensation of any nutritional deficiency in the medium. We suggest that biodegradation of PAH by bacteria attached to NAPLs can be limited by nutrient availability due to the simultaneous consumption of NAPL components, but this limitation can be overcome by interface fertilization.

[NT-proBNP in chronic obstructive pulmonary disease patients]. / NT-proBNP en pacientes con enfermedad pulmonar obstructiva crónica.

BACKGROUND: Brain natriuretic peptide (BNP) is produced and released mainly from ventricles. It has several physiological actions. BNP has been shown to be useful for diagnosis and prognosis in heart failure. The aim of this study is to analyse NT-proBNP levels in chronic obstructive pulmonary disease (COPD) patients and to distinguish factors which could modify these levels. PATIENTS AND METHODS: A descriptive and prospective study was made. COPD patients admitted due to acute exacerbation of this disease at the Hospital Universitario Lozano Blesa (Zaragoza, Spain) were included from November 1st 2004 to May 1st 2007. We included 99 patients; they had not suffered heart failure and they did not present any exclusion criteria. Blood samples were taken to determine NT-proBNP concentrations. RESULTS: Mean age was 74 years and 79% of patients were men. Medium value of NT-proBNP was 1289 pg/ml. Mean body mass index (BMI) was 27.19. There were significant differences between NT-proBNP in patients with or without atrial fibrillation and depending on their age, but there were no differences between men and women nor between patients with or without renal insufficiency. CONCLUSION: COPD patients present high serum levels of NT-proBNP during acute exacerbations and these are modified with age and atrial fibrillation. NT-proBNP could be a prognostic factor identifying COPD patients at special risk, or with a worsening clinical evolution.

Compliance with an oral hyperproteic supplement with fibre in nursing home residents.

BACKGROUND: Undernutrition is a common problem in older individuals that may be related to a low protein dietary intake. Oral supplements may improve the health status in this population, but their use may be limited by compliance and side effects. OBJECTIVES: To evaluate effects of an oral supplement of protein and fibre on compliance, on nutritional status, and on intestinal habits in nursing home residents. METHOD: A prospective observational study was carried out in 66 Spanish nursing homes. 358 subjects undernourished or at risk of undernutrition requiring nutritional supplements. After informed consent was given, subjects received 2 daily cartons (400 ml) of a liquid oral supplement rich in protein and fibre along 3 months. Supplement intake compliance was measured at baseline and after 6 and 12 weeks. Nutritional status was assessed using the Mini- Nutritional Assessment (MNA), weight, and Body Mass Index (BMI). Changes in intestinal habits and digestive symptoms were also recorded, as well as subject's supplement acceptance. RESULTS: Compliance with the supplement intake was 97.46% at 6 weeks and 96% at 12 weeks of follow-up. Significant changes (p<0.0001) were found in nutritional status: mean value of MNA improved from baseline (MNA=14.0+/-3.9) after 12 weeks (MNA=17.0+/-4.0), as well as weight (+2.1 kg, a 4.1% increase). The BMI did not change significantly (BMI=21.43 at baseline; BMI=21.78 at 12 weeks). Undernutrition prevalence (MNA<17) decreased from 76.4 to 46.6% (p<0.0001). Intestinal habits showed a significant improvement in defecation frequency (from 4.7 to 6.1 stools per week, p<0.0001) and faeces consistency (from 53.2% to 74.5% reporting formed soft stools, p<0.0001). 48.9% of the subjects considered to have better intestinal habits after 6 weeks and 50.5% after 3 months of supplementary food intake, the rest reporting no change. Vomits and flatulence were also significantly reduced (p<0.0001). CONCLUSION: The administration of an oral hyperproteic supplement with fibre in aged subjects who are undernourished or at risk of malnutrition can be done in nursing homes with a high level of compliance. Supplements improve their nutritional status and their intestinal habits.

Pancreatic duct secretion: experimental methods, ion transport mechanisms and regulation

The pancreatic ductal tree conveys enzymatic acinar products to the duodenumand secretes the fluid and ionic components of pancreatic juice. The physiology ofpancreatic duct cells has been widely studied, but many questions are still unansweredconcerning their mechanisms of ionic transport. Differences in the transportmechanisms operating in the ductal epithelium has been described both among differentspecies and in the different regions of the ductal tree. In this review we summarizethe methods developed to study pancreatic duct secretion both in vivo and invitro, the different mechanisms of ionic transport that have been reported to date inthe basolateral and luminal membranes of pancreatic ductal cells and the regulationof pancreatic duct secretion by nervous, endocrine and paracrine influences(AU)

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Pancreatic duct secretion: experimental methods, ion transport mechanisms and regulation.

The pancreatic ductal tree conveys enzymatic acinar products to the duodenum and secretes the fluid and ionic components of pancreatic juice. The physiology of pancreatic duct cells has been widely studied, but many questions are still unanswered concerning their mechanisms of ionic transport. Differences in the transport mechanisms operating in the ductal epithelium has been described both among different species and in the different regions of the ductal tree. In this review we summarize the methods developed to study pancreatic duct secretion both in vivo and in vitro, the different mechanisms of ionic transport that have been reported to date in the basolateral and luminal membranes of pancreatic ductal cells and the regulation of pancreatic duct secretion by nervous, endocrine and paracrine influences.

Calcitriol improves streptozotocin-induced diabetes and recovers bone mineral density in diabetic rats.

Vitamin D analogs exert a preventative effect on experimental diabetes, but whether or not they are able to halt progress of established diabetes is not yet known. Moreover, it is widely accepted that diabetes may induce osteoporosis, but the efficacy of vitamin D on diabetic osteoporosis is not clear. In order to help clarify these issues, we have tested the efficacy of calcitriol streptozotocin-induced diabetes. Streptozotocin (60 mg/Kg body weight) was injected in 3-month-old Wistar rats, randomly distributed into two groups: vehicle (olive oil) treated diabetic rats (D) and diabetic rats treated with 1.25-(OH)2D3 250 mg, three times a week (DT). Control animals (C) were treated with vehicle alone. The experiment lasted 8 weeks. The histology of the pancreata was evaluated. Blood glucose and calcium and phosphate in serum and urine were measured. Finally, bone mineral density (BMD) of tibia and lumbar vertebrae were evaluated. After 8 weeks, diabetes persisted in 85% of the diabetic rats (D group), but in only 45% of vitamin D-treated group (DT). At the end of the experiment, DT animals were separated into two groups, those still remaining diabetic (DT-NR) and reversed animals (DT-R). Moreover, bone loss was observed in diabetic animals (D), whereas BMD of DT-R rats showed similar values to those of controls (C). Our results suggest that 1.25(OH)2D3 improves diabetes and, as such, may recover BMD in streptozotocin-induced diabetic rats.

Chemotaxis in polycyclic aromatic hydrocarbon-degrading bacteria isolated from coal-tar- and oil-polluted rhizospheres.

Abstract The limited mass transfer in polycyclic aromatic hydrocarbon (PAH)-contaminated soils during bioremediation treatments often impedes the achievement of regulatory decontamination end-points. Little is known about bioavailability of these hydrophobic pollutants in phytoremediation systems. This work attempts to evaluate, for the first time, chemotaxis as a bioavailability-promoting trait in PAH-degrading bacteria from the rhizosphere. For this aim, 20 motile strains capable of degrading different PAHs were isolated from rhizosphere soils contaminated with coal tar and oil. Three representative Pseudomonas strains were selected, on the basis of their faster growth and/or range of PAHs degraded, for detailed chemotaxis studies with PAHs (naphthalene, phenanthrene, anthracene, and pyrene), bacterial lipopolysaccharide and root exudates from seven different plants. The chemotactic response was quantified with a new densitometric method. The results indicate that chemotaxis is a relevant mobilizing factor for PAH-degrading rhizosphere bacteria.

Bioavailability of solid and non-aqueous phase liquid (NAPL)-dissolved phenanthrene to the biosurfactant-producing bacterium Pseudomonas aeruginosa 19SJ.

The biodegradation of phenanthrene by the biosurfactant-producing strain Pseudomonas aeruginosa 19SJ was investigated in experiments with the compound present either as crystals or dissolved in non-aqueous phase liquids (NAPLs). Growth on solid phenanthrene exhibited an initial phase not limited by dissolution rate and a subsequent, carbon-limited phase caused by exhaustion of the carbon source. Rhamnolipid biosurfactants were produced from solid phenanthrene and appeared in solution and particulate material (cells and phenanthrene crystals). During the carbon-limited phase, the concentration of rhamnolipids detected in culture exceeded the critical micelle concentration (CMC) determined with purified rhamnolipids. The biosurfactants caused a significant increase in dissolution rate and pseudosolubility of phenanthrene, but only at concentrations above the CMC. Externally added rhamnolipids at a concentration higher than the CMC increased the biodegradation rate of solid phenanthrene. Mineralization curves of low concentrations of phenanthrene initially dissolved in two NAPLs [2,2,4,4,6,8,8-heptamethylnonane and di(2-ethylhexyl)phthalate] were S-shaped, although no growth was observed in the population of suspended bacteria. Biosurfactants were not detected in solution under these conditions. The observed mineralization was attributed not only to suspended bacteria, but also to bacterial populations growing at the NAPL-water interface, mineralizing the compound at higher rates than predicted by abiotic partitioning. We suggest that rhamnolipid production and attachment increased the bioavailability of phenanthrene, so promoting biodegradation activity.

Protective effect of long term high fiber diet consumption on rat exocrine pancreatic function after chronic ethanol intake.

The effects of ethanol administration on exocrine pancreas have been widely studied, but little is known about the effect of dietary fiber in combination with chronic ethanol on exocrine pancreatic function. The aim of this work was to examine the chronic effects of a high fiber diet, ethanol ingestion, and a combination of both on the function of the rat exocrine pancreas. Four groups of rats were fed for six months the following diets: 1.- NW: standard laboratory diet; 2.- FW: high fiber diet (15% cellulose); 3.- NE: standard laboratory diet and 20% ethanol in the drinking water; and 4.- FE: high fiber diet and 20% ethanol. Cholecystokinin (CCK) and acetylcholine (Ach) effects on amylase release and intracellular calcium mobilization in pancreatic acini were studied. In rats fed a 20% ethanol (NE), both the basal amylase release and the basal [Ca(2+)](i) were significantly increased; nonetheless, CCK and Ach-induced amylase release were significantly reduced compared with control rats. Ach- but not CCK-stimulated [Ca(2+)](i) increase in NE rats was significantly decreased compared with NW. In rats fed a combination of ethanol and a high fiber diet (FE) all the parameters under study were not significantly affected compared to control rats (NW). In conclusion, high fiber consumption does not alter the function of the exocrine pancreas. However, it ameliorates the deleterious effect of chronic ethanol consumption on pancreatic amylase secretion and, at least partially, reverses the ethanol-induced alterations on [Ca(2+)](i) in the rat exocrine pancreas.

Nitric oxide stimulates tyrosine phosphorylation of p125(FAK) and paxillin in rat pancreatic acini.

Some of the effects of several oncogenes, integrins, growth factors, and neuropeptides are mediated by tyrosine phosphorylation of the non-receptor tyrosine kinase p125(FAK) and the cytoskeletal protein paxillin. We have demonstrated that different stimuli cause tyrosine phosphorylation of p125(FAK) and paxillin in rat pancreatic acini. The aim of the present study was to determine whether exogenous NO activates this pathway. We demonstrate that in isolated rat pancreatic acini, a NO donor, sodium nitroprusside (SNP) stimulates, in a dose- and time-dependent way, tyrosine phosphorylation of p125(FAK) and paxillin. The same effects could be observed after incubating acini with 8-Br-cGMP. Moreover, the stimulation caused by SNP was completely abolished by two different guanylyl cyclase inhibitors, methylene blue, and LY-83583. These inhibitors also diminished unstimulated phosphorylation of p125(FAK) and paxillin. We conclude that in rat pancreatic acini exogenous NO causes p125(FAK) and paxillin tyrosine phosphorylation that is mediated by a guanylyl cyclase-dependent pathway.

Influence of chronic ethanol consumption on the muscarinic cholinergic control of rat pancreatic acinar cells.

There are a number of hypothetical explanations for the actions of ethanol on the exocrine pancreas; among them, the cholinergic hypothesis has received special attention. According to this hypothesis, chronic alcohol consumption induces alterations in the control of exocrine pancreatic function resulting in cholinergic hyperstimulation of pancreatic acinar cells and their muscarinic receptors. Our aim was to investigate the cholinergic control of pancreatic enzyme secretion and the number and affinity of muscarinic receptors in the pancreatic acinar cells of rats subjected to chronic ethanol ingestion. We also investigated whether a high-fibre diet modifies the actions of ethanol on these aspects of the exocrine pancreatic function. Four groups of rats received either a standard or a high fibre diet, and either water or 20% (v/v) ethanol. After 6 months of treatment, isolated pancreatic acini were used for the determination of carbachol-stimulated amylase secretion and for the analysis of muscarinic receptors, using 1-[N-methyl-3H]scopolamine as a radioligand. Neither chronic ethanol intake nor a high fibre diet caused any apparent alteration in pancreatic histology, neither did them modify plasmatic amylase levels. Chronic alcoholization resulted in a significant increase in the amylase released from pancreatic acini in response to carbachol stimulation, but it did not affect either the number or the affinity of pancreatic acinar muscarinic receptors. The actions of ethanol are not significantly modified by the simultaneous consumption of a high fibre diet.

Effect of humic fractions and clay on biodegradation of phenanthrene by a Pseudomonas fluorescens strain isolated from soil.

The mineralization of phenanthrene in pure cultures of a Pseudomonas fluorescens strain, isolated from soil, was measured in the presence of soil humic fractions and montmorillonite. Humic acid and clay, either separately or in combination, shortened the acclimation phase. A higher mineralization rate was measured in treatments with humic acid at 100 microg/ml. Humic acid at 10 microg/ml stimulated the transformation only in the presence of 10 g of clay per liter. We suggest that sorption of phenanthrene to these soil components may result in a higher concentration of substrate in the vicinity of the bacterial cells and therefore may increase its bioavailability.

Low bone density with normal bone turnover in ovariectomized and streptozotocin-induced diabetic rats.

Diabetes and estrogen deficit are known causes of osteopenia, diabetes being associated with a low bone turnover and estrogen deficit with a high bone turnover. In the present work, we studied the effect of combined ovariectomy and diabetes on bone mineral content (BMC) and bone mineral density (BMD) and several bone markers in the rat. Four groups of rats were studied: control (C), ovariectomized (O), diabetic (D), and ovariectomized and diabetic (DO). Twelve weeks after starting the experiments, BMC and BMD of the first six lumbar vertebrae were measured; a bone formation marker (BGP) and a bone resorption marker (free collagen cross-links, PYD) were also analyzed. Diabetic rats showed diminished gain in bone mass, BMC (D: 0.417 +/- 0.028 g, DO: 0.422 +/- 0.020 g) and BMDs (D: 0.171 +/- 0.006 g/cm2, DO: 0.174 +/- 0.006 g/cm2) both being significantly (P < 0.001) lower than those of control (C: BMC 0.727 +/- 0.024 g and BMD 0.258 +/- 0.004 g/cm2) and ovariectomized (O: BMC 0.640 +/- 0.044 g and BMD 0.240 +/- 0.009 g/cm2) groups. Moreover, the BMC and BMD of the C group were significantly (P < 0.05) higher than that of the O group. BGP and PYD levels were significantly (P < 0.01) higher in the O group (BGP: 138.2 +/- 16.8 ng/ml, PYD: 270.2 +/- 17.8 nM/mM) than those found in the control rats (BGP: 44.7 +/- 4.8 ng/ml, PYD: 165.6 +/- 12.5 nM/mM); the D group showed significantly (P < 0.01) lower values (BGP: 27.4 +/- 14.6 ng/ml, PYD: 55.0 +/- 7.4 nM/mM) than those of the control group. The DO group showed similar levels (BGP: 43.4 +/- 5.1 ng/ml, PYD: 146.7 +/- 14.6 nM/mM) to those found in the C group. Although bone marker levels in the O and D groups were in accordance with those expected in these situations, in the DO group the corresponding levels are apparently "normal." Also, the decrease of gain in bone mass observed after combining estrogen deficit and diabetes (DO group) did not seem to be more marked than that caused by diabetes alone.

Impairment of intracellular calcium homoeostasis in the exocrine pancreas after caerulein-induced acute pancreatitis in the rat.

1. We have measured intracellular calcium concentrations in basal conditions and in response to cholecystokinin-octapeptide and acetylcholine in pancreatic acini isolated from rats with caerulein-induced acute pancreatitis and compared them with those in control rats. 2. We also measured amylase secretion in basal conditions and in response to cholecystokinin-octapeptide in both groups. 3. In pancreatic acini from rats with pancreatitis the basal intracellular calcium concentration was significantly increased (134.9 +/- 7.1 nmol/l compared with 71.8 +/- 2.9 nmol/l, P < 0.001). Moreover, the maximum values of intracellular calcium attained during the stimulation period were equivalent in acini from control and pancreatitic rats with no statistically significant differences. 4. In acini from control rats the differences between the resting levels of intracellular calcium and the maximum intracellular calcium values (delta[Ca2+]i) in response to several concentrations of cholecystokinin-octapeptide showed a clear dose-response relationship, with a half-maximal increase at 0.1 nmol/l and a maximal difference (delta[Ca2+]i = 259 +/- 50 nmol/l) at 1 nmol/l. In contrast, a right-shifted response, with a statistically significant smaller increase, was observed in acini from pancreatitic rats. 5. Basal amylase release was significantly higher in acini from rats with pancreatitis (11.7 +/- 1.0% of total compared with 5.9 +/- 1.1% of total, P < 0.001). In contrast, cholecystokinin-octapeptide and acetyl-choline-evoked amylase secretion was reduced by more than 85% in acini from pancreatitic rats. 6. In conclusion, calcium homoeostasis in pancreatic acinar cells from rats with caerulein-induced pancreatitis seems to be impaired. These results suggest excessive release of acinar free ionized calcium, or damage to the integrity of mechanisms that restore low resting levels of intracellular free ionized calcium, and the consequent calcium toxicity could be the key trigger in caerulein-induced acute pancreatitis.

Description of an automated method for the in vitro measurement of trypsinogen secretion from pancreatic segments.

The characterization of trypsinogen output from superfused pancreatic tissue by an automated spectrophotometric method is described. To test the method we investigated the time-course and the dose-response curve for acetylcholine-induced trypsinogen release from superfused pancreatic segments. We have demonstrated that this method allows the on-line detection and estimation of trypsinogen release with suitability, stability, and sensitivity.

Heterogeneous decrease of bone mineral density in the vertebral column of ovariectomized rats.

The long-term effect of ovariectomy on the loss of bone mineral density (BMD) was evaluated in rats with and without estrogen treatment; BMD was studied in the lumbar and caudal vertebrae, measured by DXA, to find how the losses of BMD occur in the axial skeleton. Seventy female Wistar rats of 3 months of age were divided into four groups as follows: group 1: control animals; group 2: ovariectomized animals; group 3: ovariectomized animals undergoing treatment with estrogen (0.25 mg/kg per week of 17-beta estradiol); group 4: ovariectomized rats undergoing estrogen treatment only during the last 3 months of the experimental period. No significant differences were found among the groups in regard to the BMD values of the caudal vertebrae at either 3 or 6 months. Likewise, in the lumbar vertebrae there were no significant differences among the groups after 3 months. However, at 6 months, a decrease in the BMDs of the ovariectomized animals with respect to the remaining groups was found: 226 +/- 11 mg/cm2 in the ovariectomized group; 262 +/- 14 mg/cm2 in the controls; 255 +/- 4 mg/cm2 in the rats receiving estrogen treatment for 6 months; and 259 +/- 5 mg/cm2 in the animals receiving estrogen for 3 months. The study also reveals the absence of differences in the bone mineral density between the ovariectomized and control rats when the former received estrogen treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Dose-response effects of VIP on the rabbit exocrine pancreatic secretion. Comparison with PACAP-27 actions.

A dose-response study of the effects of vasoactive intestinal peptide (VIP) on the exocrine pancreatic secretion of the rabbit has been made. Furthermore, the actions of VIP and pituitary adenylate cyclase activating peptide (PACAP) on the exocrine pancreatic secretion were compared at a similar molar dose. After the infusion of VIP a linear dose-response relationship for pancreatic flow rate and bicarbonate output, up to the dose of 4 micrograms/kg, was observed. VIP acts as a partial agonist of secretin, the rabbit pancreas being less sensitive to VIP compared with other mammals. Moreover, VIP did not significantly stimulate the pancreatic protein output. PACAP stimulated the hydroelectrolyte fraction of the exocrine pancreatic secretion in a similar manner to that of VIP. Unlike what was observed with VIP, PACAP, on the same molar basis, significantly stimulated the protein and amylase outputs. Furthermore, PACAP releases VIP, so that the action of PACAP on the hydroelectrolyte fraction may be partially mediated by VIP; on the other hand, VIP is not involved in the effect of PACAP on the pancreatic enzyme secretion of this species.

Cholinergic pathways are involved in secretin and VIP release and the exocrine pancreatic response after intraduodenally perfused acetic and lactic acids in the rat.

The response of the exocrine pancreas to intraduodenal perfusion of acetic and lactic acids in normal and previously atropinized rats was studied. Secretin and vasoactive intestinal peptide (VIP) plasma levels in portal plasma were also measured. Intraduodenal perfusion of both acetic and lactic acids significantly stimulated flow rate (from 0.29 +/- 0.03 microliters/min to a maximum of 1.06 +/- 0.08 microliters/min after acetic and from 0.35 +/- 0.05 microliters/min to a maximum of 1.13 +/- 0.12 microliters/min after lactic acid perfusion) and protein output (from 11.16 +/- 2.33 micrograms/min to a maximum of 35.1 +/- 7.4 micrograms/min after acetic and from 8.98 +/- 0.95 micrograms/min to a maximum of 22.5 +/- 1.3 micrograms/min after lactic acid perfusion). Atropine treatment significantly inhibited pancreatic flow rate and protein output after acetic acid perfusion, but no inhibition of flow rate and a slight decrease in the protein output after lactic acid perfusion were seen. With respect to plasma peptide concentrations, significant increases in secretin and VIP levels were found after perfusion of both organic acids; atropine administration significantly decreased plasma secretin levels after acetic acid administration although it did not affect plasma VIP concentrations. By contrast, atropine significantly increased plasma secretin levels, but significantly lower values of plasma VIP concentrations were observed after lactic acid perfusion. Therefore, cholinergic mechanisms are involved in the release of secretin and VIP and different types of control of exocrine pancreatic secretion occur, depending on the features of the intraduodenal stimulant.