Novel nonylphenol-degrading bacterial strains isolated from sewage sludge: Application in bioremediation of sludge.

Nonylphenol (NP) is an anthropogenic pollutant frequently found in sewage sludge due to the insufficient degrading effectiveness of conventional WWTPs and has attracted attention as an endocrine disruptor. The aim of this study was to isolate specific NP-degrading bacteria from sewage sludge to be used in the degradation of this contaminant through bioaugmentation processes in aqueous solution and sewage sludge. Up to eight different bacterial strains were isolated, six of them not previously described as NP degraders. Bacillus safensis CN12 presented the best NP degradation in solution, and glucose used as an external carbon source increased its effect, reaching DT50 degradation values (time to decline to half the initial concentration of the pollutant) of only 0.9 days and a complete degradation in <7 days. Four NP metabolites were identified throughout the biodegradation process, showing higher toxicity than the parent contaminant. In sewage sludge suspensions, the endogenous microbiota was capable of partially degrading NP, but a part remained adsorbed as bound residue. Bioaugmentation was used for the first time to remove NP from sewage sludge to obtain more environmentally friendly biosolids. However, B. safensis CN12 was not able to degrade NP due to its high adsorption on sludge, but the use of a cyclodextrin (HPBCD) as availability enhancer allowed us to extract NP and degrade it in solution. The addition of glucose as an external carbon source gave the best results since the metabolism of the sludge microbiota was activated, and HPBCD was able to remove NP from sewage sludge to the solution to be degraded by B. safensis CN12. These results indicate that B. safensis CN12 can be used to degrade NP in water and sewage sludge, but the method must be improved using consortia of B. safensis CN12 with other bacterial strains able to degrade the toxic metabolites produced.

Bioremediation of a trifluralin contaminated soil using bioaugmentation with novel isolated bacterial strains and cyclodextrin.

Trifluralin (TFL) is a highly persistent with a strong adsorption capacity on soil particles herbicide. This study was to isolate microbial consortia and bacterial strains from a soil with a historical application of pesticides to evaluate their potential to degrade TFL in soil. Different bioremediation techniques were considered for increasing the effectiveness of TFL degradation in soil. These techniques consisted of: i) biostimulation, using a nutrients solution (NS); ii) bioaugmentation, using a natural microbial consortium (NMC), seven individual bacterial strains isolated from NMC, and an artificial bacterial consortium formed by the seven TFL-degrading bacterial strains (ABC); iii) bioavailability enhancement, using a biodegradable compound, a randomly methylated cyclodextrin, RAMEB. Biostimulation using NS leads up to 34 % of soil TFL biodegraded after 100 d. When the contaminated soil was inoculated with NMC or ABC consortia, TFL loss increased up to 62 % and 74 %, respectively, with DT50 values (required time for the pollutant concentration to decline to half of its initial value) of 5.9 and 11 d. In the case of soil inoculation with the isolated individual bacterial strains, the extent of TFL biodegradation ranged widely from 2.3 % to 55 %. The most efficient bacterial strain was Arthrobacter aurescens CTFL7 which had not been previously described in the literature as a TFL-degrading bacterium. Bioaugmentation with CTFL7 bacterium was also tested in the presence of RAMEB, provoking a drastic increase in herbicide biodegradation up to 88 %, achieving a DT50 of only 19 d. Cyclodextrins had never been tested before for enhancement of TFL biodegradation. An ecotoxicity assay was performed to confirm that the proposed bioremediation techniques were also capable to reduce toxicity. A Microtox® test showed that after application A. aurescens CTF7 and A. aurescens CTF7 + RAMEB, the TFL-contaminated soil, which initially presented acute toxicity, became non-toxic at the end of the biodegradation experiments.

Dissipation of a mix of priority PAHs in soils by using availability enhancers. Effect of aging and pollutant interactions.

A remediation strategy using three non-toxic availability enhancers (two cyclodextrins and a rhamnolipid biosurfactant) was applied to various soils artificially contaminated with a mix of Polycyclic Aromatic Hydrocarbons (PAHs) considered priority pollutants at two levels of contamination: only with 7 low molecular weight PAHs (LMW PAHs, 5 with 3-ring and 2 with 4-ring - fluoranthene and pyrene) or with 14 PAHs (from 3 to 6 rings). Natural attenuation of PAHs in all soils showed degradation capacity for the LMW PAHs, with a final content of LMW PAHs <5% of their initial concentration. Conversely, the rest of PAHs (high molecular weight PAHs, HMW) remained in the soils (61% - 83.5%), indicating abiotic dissipation of HMW PAHs due to formation of non-extractable residues in soils. The influence of the presence of HMW PAHs on the degradation of the 7 LMW PAHs was also tested, showing a general decrease in the time to obtain 50% dissipation (DT50), statistically significant for acenaphthene, acenaphthylene and fluorene. Availability enhancers showed different effects on PAHs dissipation. 2-hydroxypropyl-ß-cyclodextrin (HP) decreased DT50 of some of the lighter PAHs, whereas the rhamnolipid (RL) caused a slight DT50 increase due to its initial toxicity on native soil microorganisms, but showing later high degradation rate for LMW PAHs. On the contrary, randomly methylated-ß-cyclodextrin (RAMEB) slowed down PAHs degradation due to its high adsorption onto soil surface, blocking the desorption of PAHs from the soils. The high number of experimental factors not studied simultaneously before (soil type, co-contamination, availability enhancers and incubation time) allowed to conduct a statistical analysis which supported the conclusions reached. Principal Component Analysis separated the studied PAHs in 3 groups, in relation with their molecular weight and Kow. The first principal component was related with LMW PAHs, and separate the inefficient RAMEB from the other availability enhancers.

The chaperonin CCT controls T cell receptor-driven 3D configuration of centrioles.

T lymphocyte activation requires the formation of immune synapses (IS) with antigen-presenting cells. The dynamics of membrane receptors, signaling scaffolds, microfilaments, and microtubules at the IS determine the potency of T cell activation and subsequent immune response. Here, we show that the cytosolic chaperonin CCT (chaperonin-containing TCP1) controls the changes in reciprocal orientation of the centrioles and polarization of the tubulin dynamics induced by T cell receptor in T lymphocytes forming an IS. CCT also controls the mitochondrial ultrastructure and the metabolic status of T cells, regulating the de novo synthesis of tubulin as well as posttranslational modifications (poly-glutamylation, acetylation, Δ1 and Δ2) of αß-tubulin heterodimers, fine-tuning tubulin dynamics. These changes ultimately determine the function and organization of the centrioles, as shown by three-dimensional reconstruction of resting and stimulated primary T cells using cryo-soft x-ray tomography. Through this mechanism, CCT governs T cell activation and polarity.

Soil bioremediation by cyclodextrins. A review.

Remediation of soils contaminated by organic pollutants has become an urgent necessity worldwide. A wide variety of techniques have been developed but many of them are associated with drawbacks (complexity, high costs, environmental risks, etc.). Bioremediation, the use of living organisms to remediate polluted sites, is an alternative approach considered a cost-effective and more environmentally friendly technique, but the low bioavailability of the organic pollutants in soils is its main limitation. Cyclodextrins have been proposed as a ́greener alternative to organic solvents or synthetic surfactants for increasing organics bioavailability in soils. Cyclodextrins can form inclusion complexes with hydrophobic pollutants increasing their aqueous solubility and enhancing their bioremediation in soils. This review gives an overview on the use of cyclodextrins for this purpose, highlighting the advantages and disadvantages and perspectives of this technology for future research. The effect of those cyclodextrins more commonly used is analyzed, particularly hydroxypropyl-ß-cyclodextrin (HPBCD) and randomly methylated-ß-cyclodextrin (RAMEB), as well as some of the more common contaminants treated (almost 80% are industrial chemicals and the rest are pesticides) and the bioremediation strategies used (by microorganisms and/or phytoremediation). The review also provides a critical view on knowledge gaps and limitations of this technology which must be overcome to bring it for field-scale application.

Extraction of nonylphenol, pyrene and phenanthrene from sewage sludge and composted biosolids by cyclodextrins and rhamnolipids.

Sewage sludge generated by Waste Water Treatment Plants (WWTPs) are frequently used as organic amendments in agriculture, but they contain pollutants such as Potentially Toxic Elements (PTEs) and organic contaminants which contaminate the agricultural soils. The study presented here is part of a larger study based on the application of environmentally friendly chemical and biological techniques to decrease the content of organic pollutants in sewage sludge before agricultural application. The aim of this study was to evaluate the performance of biodegradable extractants, such as some cyclodextrins (CDs), ß-cyclodextrin (BCD), hydroxypropyl-ß-cyclodextrin (HPBCD) and randomly methylated-ß-cyclodextrin (RAMEB), and a biosurfactant (rhamnolipid, RL) on the removal and availability of pyrene (PYR), phenanthrene (PHE) and nonylphenol (NP) from several biosolids samples in order to improve their subsequent biodegradation. The influence of pollutants retention time on biosolids was studied, as well as the effect of each extractant on PTEs solubilization. Results obtained were pollutant and extractant-dependent. BCD extracted similar amounts of pollutants compared to water, whereas HPBCD and RAMEB actually increased the availability of the three pollutants in most of the samples and aging times. RL seems to be the best election for Polycyclic Aromatic Hydrocarbons (PAHs) extraction from biosolids, with percentages of extraction multiplied by more than 80 and 40 times for PHE and PYR, respectively, relative to water extraction. The extraction enhancement was the highest for NP, the most hydrophobic pollutant, reaching more than 500-fold higher with HPBCD and RAMEB. PTEs extractability was not affected by the different CDs used, but RL caused an increment in their soluble content what could endanger a subsequent biodegradation of the organic pollutants.

Mechanisms of polarized cell-cell communication of T lymphocytes.

Cell-cell communication comprises a variety of molecular mechanisms that immune cells use to respond appropriately to diverse pathogenic stimuli. T lymphocytes polarize in response to different stimuli, such as cytokines, adhesion to specific ligands and cognate antigens presented in the context of MHC. Polarization takes different shapes, from migratory front-back polarization to the formation of immune synapses (IS). The formation of IS between a T cell and an antigen-presenting cell involves early events of receptor-ligand interaction leading to the reorganization of the plasma membrane and the cytoskeleton to orchestrate vesicular and endosomal traffic and directed secretion of several types of mediators, including cytokines and nanovesicles. Cell polarization involves the repositioning of many subcellular organelles, including the endosomal compartment, which becomes an effective platform for the shuttling of molecules as vesicular cargoes that lately will be secreted to transfer information to antigen-presenting cells. Overall, the polarized interaction between a T cell and APC modifies the recipient cell in different ways that are likely lineage-dependent, e.g. dendritic cells, B cells or even other T cells. In this review, we will discuss the mechanisms that mediate the polarization of different membrane receptors, cytoskeletal components and organelles in T cells in a variety of immune contexts.

Natural and assisted dissipation of polycyclic aromatic hydrocarbons in a long-term co-contaminated soil with creosote and potentially toxic elements.

An enhanced bioremediation strategy was applied to an industrial soil co-contaminated with Polycyclic Aromatic Hydrocarbons (PAHs) and Potentially Toxic Elements (PTEs). Hydroxypropyl-ß-cyclodextrin (HPBCD) and a natural mixture of two rhamnolipids (RL) were added to increase PAHs bioavailability, and combined with a microbial consortium (MC) to biodegrade soil PAHs. Bioavailability of only six PAHs (3-, 4-ring PAHs) increased when using HPBCD, with a maximum increase about 2.8-fold higher. The highest dose of HPBCD (5%) enhanced PAH degradation, with the best results for 4-ring PAHs with treatments of HPBCD + MC (up to 48% degradation for pyrene and 43% for fluoranthene), whereas dissipation for 5-ring PAHs was very low and for 6-ring was negligible. The use of RL increased the bioavailability of 13 of the 16 PAHs studied, reaching up to 60-fold higher values for phenanthrene or 18-fold higher for acenaphtene. RL addition did not show degradation improvement in any situation, and even inhibited the scarce degradation observed in the control treatment. The high increase in availability of both PAHs and mainly PTEs when using RL as amendment could make them toxic for microorganisms. In fact, Microtox Acute Toxicity test using Aliivibrio fischeri and the absence of colony forming units (CFUs) of indigenous bacteria demonstrated the extremely high levels of toxicity in RL treated soil.

Atomic Force Microscopy of Protein Shells: Virus Capsids and Beyond.

In Atomic Force Microscopy (AFM) the probe is a nanometric tip located at the end of a microcantilever which palpates the specimen under study as a blind person uses a white cane. In this way AFM allows obtaining nanometric resolution images of individual protein shells, such as viruses, in liquid milieu. Beyond imaging, AFM also enables the manipulation of single protein cages, and the characterization a variety physicochemical properties able of inducing any measurable mechanical perturbation to the microcantilever that holds the tip. In this chapter we start revising some recipes for adsorbing protein shells on surfaces. Then we describe several AFM approaches to study individual protein cages, ranging from imaging to spectroscopic methodologies devoted to extracting physical information, such as mechanical and electrostatic properties.

Immune cells from patients with psoriasis are defective in inducing indoleamine 2,3-dioxygenase expression in response to inflammatory stimuli.

BACKGROUND: Indoleamine 2,3-dioxygenase (IDO) is an inducible enzyme that suppresses the immune response. The role of IDO as a negative regulator of inflammatory responses has been documented in several experimental autoimmune diseases. OBJECTIVES: To explore the regulation of IDO by immune cells in psoriasis and its relation with disease severity. METHODS: The expression and activity of IDO were assessed by reverse-transcriptase polymerase chain reaction, flow cytometry and high-performance liquid chromatography in peripheral blood of patients with moderate-to-severe plaque-type psoriasis. The ability of immune cells to express IDO in response to inflammatory stimuli was studied. The functional role of IDO expression was evaluated in a regulatory T cell (Treg) differentiation assay, using cocultures of immature monocyte-derived dendritic cells with autologous peripheral CD4+ T cells. RESULTS: Analysis of the kynurenine-to-tryptophan ratio in serum samples indicated higher IDO activity in patients with psoriasis than in healthy controls. However, correlation studies showed lower IDO activity in those patients with higher Psoriasis Area and Severity Index (PASI). Although myeloid dendritic cells from patients with psoriasis expressed higher levels of IDO than those from healthy controls, these cells did not upregulate IDO in response to a combination of tumour necrosis factor-α, interleukin (IL)-1ß and IL-6 cytokines. The defective expression of IDO correlated with PASI. Immature monocyte-derived dendritic cells from patients with psoriasis also expressed low levels of IDO and induced CD4+ Treg differentiation poorly. CONCLUSIONS: Immune cells from patients with psoriasis have a defect in upregulating IDO in response to inflammation associated with the severity of psoriasis.

Natural attenuation of fluorene and pyrene in contaminated soils and assisted with hydroxypropyl-ß-cyclodextrin. Effect of co-contamination.

The objectives of this study were to investigate the mutual effect of the PAHs fluorene and pyrene on their respective biodegradation and dissipation processes in an agricultural soil, and to determine the effect of hydroxypropyl-ß-cyclodextrin (HPBCD), used to increase the bioavailability of PAHs, on such processes. Fluorene dissipation was primarily due to abiotic processes, although a small contribution from biodegradation was also observed. Therefore, fluorene dissipation did not increase with HPBCD and its presence did not significantly alter the dehydrogenase activity. In contrast to fluorene, pyrene dissipation depended primarily on biotic factors, with endogenous soil microorganisms capable of degrading pyrene, with large increases in dehydrogenase activity. HPBCD increased biodegradation rate of pyrene. The co-contamination of soil with both PAHs did not affect fluorene evolution, but significantly inhibited pyrene biodegradation. The different abilities of soil bacterial consortia to catabolize these PAHs are discussed. Additionally, the possibility that the abiotic loss of fluorene through volatilization had a significant effect on the microbial community biodegradation of both fluorene and pyrene is examined.

Effect of contact time and the use of hydroxypropyl-ß-cyclodextrin in the removal of fluorene and fluoranthene from contaminated soils.

Sorption-desorption experiments of fluorene (FLU) and fluoranthene (FLT) in soils were carried out and correlated to their removal from aged contaminated soils using aqueous solutions in the absence and in the presence of hydroxypropyl-ß-cyclodextrin (HPBCD) as the extraction agent. FLU became more resistant to extraction in aged contaminated soils due to its initial adsorption onto the mineral and amorphous soil organic matter (SOM) domains, sites of lower binding energy from which, due to its small size, it could spread towards the condensed SOM as the contact time increased. Therefore, FLU will not be easily desorbed from aged contaminated soils due to physical entrapment mechanisms, even when using HPBCD as extractant, presenting FLU low risks to the environment. On the contrary, FLT was extracted from aged soils in the presence of HPBCD in solutions to a much greater extent than in its absence. Due to its more hydrophobic character FLT sorption in soils was relatively quicker, remaining more or less fixed on hydrophobic sites of the organic matter (OM) with different energies, and therefore the amount of FLT extracted was almost constant for different ageing times. During extraction experiments, the influence of the OM quality of the soils was also highlighted because an inverse proportionality between OM content of soil and extractability of sorbed FLT was observed. It was concluded that soils with lower OM content that had more diagenetically processed OM could block the extraction of FLT more effectively than soils with higher OM content that are less humified. This indicates the need to use not only adsorption-desorption data in contaminant fate and transport models, but also extraction studies in aged contaminated soils and other complementary analytical approaches when assessing soil contamination-related risks.

CD81 controls sustained T cell activation signaling and defines the maturation stages of cognate immunological synapses.

In this study, we investigated the dynamics of the molecular interactions of tetraspanin CD81 in T lymphocytes, and we show that CD81 controls the organization of the immune synapse (IS) and T cell activation. Using quantitative microscopy, including fluorescence recovery after photobleaching (FRAP), phasor fluorescence lifetime imaging microscopy-Föster resonance energy transfer (phasorFLIM-FRET), and total internal reflection fluorescence microscopy (TIRFM), we demonstrate that CD81 interacts with ICAM-1 and CD3 during conjugation between T cells and antigen-presenting cells (APCs). CD81 and ICAM-1 exhibit distinct mobilities in central and peripheral areas of early and late T cell-APC contacts. Moreover, CD81-ICAM-1 and CD81-CD3 dynamic interactions increase over the time course of IS formation, as these molecules redistribute throughout the contact area. Therefore, CD81 associations unexpectedly define novel sequential steps of IS maturation. Our results indicate that CD81 controls the temporal progression of the IS and the permanence of CD3 in the membrane contact area, contributing to sustained T cell receptor (TCR)-CD3-mediated signaling. Accordingly, we find that CD81 is required for proper T cell activation, regulating CD3ζ, ZAP-70, LAT, and extracellular signal-regulated kinase (ERK) phosphorylation; CD69 surface expression; and interleukin-2 (IL-2) secretion. Our data demonstrate the important role of CD81 in the molecular organization and dynamics of the IS architecture that sets the signaling threshold in T cell activation.

Reduced expression of galectin-1 and galectin-9 by leucocytes in asthma patients.

Accumulating evidence shows that galectins play roles in the initiation and resolution phases of inflammatory responses by promoting anti- or proinflammatory effects. This study investigated the presence of three members of the galectin family (galectin-1, -3 and -9) in induced sputum samples of asthma patients, as well as their possible implication in the immunopathogenesis of human asthma. Levels of interleukin (IL)-5, IL-13, and galectins were determined in leucocytes isolated from induced sputum samples by reverse transcription-polymerase chain reaction (RT-PCR) immunofluorescence and flow cytometry. High levels of IL-5 and IL-13 mRNA were detected in sputum cells from asthma patients. In parallel, immunoregulatory proteins galectin-1 and galectin-9 showed a reduced expression on macrophages from sputum samples compared with cells from healthy donors. In-vitro immunoassays showed that galectin-1 and galectin-9, but not galectin-3, are able to induce the production of IL-10 by peripheral blood mononuclear cells from healthy donors. These findings indicate that macrophages from sputum samples of asthma patients express low levels of galectin-1 and galectin-9, favouring the exacerbated immune response observed in this disease.

Effects of the presence of a composted biosolid on the metal immobilizing action of an urban soil.

The influence of a composted biosolid from urban wastewater treatment on the retention and solubility of Cu, Pb or Zn added to a soil was studied by batch adsorption/desorption experiments, equilibrating both materials and their mixtures with solutions containing various metal concentrations. The composted biosolid adsorbed less Cu or Pb and slightly more Zn than the soil, and thus caused a noticeable decrease in the retention of Cu or Pb and an increase in Zn adsorption by soil-biosolid mixtures, but these effects in the mixtures were not additive for any metal. The pH effects were studied by means of (log metal concentration)/pH diagrams. It was shown that Cu behaviour was different from that of the other metals: the relation between pH and Cu concentrations suggested similar solubilities in the presence of the biosolid and the mixtures, whereas the biosolid-free soil gave data located on a region of the diagram corresponding to slightly lower solubility. In the case of Pb or Zn, the data for the biosolid were located in a region of the diagram corresponding to clearly lower solubilities than those for the biosolid/soil mixtures. It was concluded that the biosolid has little effect on metal solubility when it is mixed with the soil in the proportions used here.

Inhibition of tumour necrosis factor and IL-17 production by leflunomide involves the JAK/STAT pathway.

OBJECTIVE: To study the effects of different disease-modifying antirheumatic drugs (DMARD) on different events mediated by IL-15-activated lymphocytes. METHODS: Peripheral blood lymphocytes (PBL) were isolated from healthy donors and activated with IL-15 after exposure to different DMARD: leflunomide, cyclosporin A, methotrexate, mycophenolic acid, FK-506, sulphasalazine and sodium aurothiomalate. The expression of different surface molecules on the PBL was then determined by flow cytometry. Cells were also co-cultured with the monocytic cell line THP-1 and the tumour necrosis factor (TNF) concentration in the supernatant was measured after 24 h using an immunoenzyme assay. The effect of the aforementioned drugs on IL-17 production by IL-15-activated PBL was also studied. RESULTS: Treatment of PBL with leflunomide, cyclosporin A and FK-506 inhibited the IL-15-induced expression of both CD54 and CD69 by PBL, as well as TNF production in co-cultures of activated PBL and THP-1 cells. The downregulation of CD54 and CD69 in PBL was correlated with the inhibition of TNF production. Likewise, leflunomide, cyclosporin A and FK-506 all inhibited IL-17 production in IL-15-activated PBL. Interestingly, the effect of leflunomide was not reverted by the presence of uridine in the medium. In addition, leflunomide inhibited the phosphorylation of STAT6 in vitro. CONCLUSION: Inhibition of the JAK/STAT pathway may represent an additional effect of leflunomide in chronic polyarthritis because it impairs certain events that control proinflammatory TNF and IL-17 cytokine production.

Availability and bio-accessibility of metals in the clay fraction of urban soils of Sevilla.

The availability of Cd, Cr, Cu, Ni, Mn, Pb and Zn present in the finest size particles of urban soils is studied by comparing the concentrations in the clay fraction with those extracted from the whole soil by either single-extraction or sequential extraction method. Many metals are preferentially present in the finest particles as compared to coarser fractions. This is true for most metals studied, except Mn and, perhaps, Cd. Those metals present in the clay fraction are often in easily bio-accessible forms, especially Cu, Pb and Zn. The results suggest that bio-accessible forms of these three metals are distributed among the three sequential fractions, and even the fraction considered as 'residual' is also bio-accessible to a significant extent. The statistical analysis shows some distinctions among metals that are compared to the 'urban', 'natural', or intermediate behaviour of the various metals as proposed earlier in the literature.

Availability and bioaccessibility of metals in fine particles of some urban soils.

Metals in urban soils might be transferred to humans via ingestion, dermal contact, or breathing, especially to children due to the "hand to mouth" activity during outdoor activities in playground and recreational areas. This involuntary soil ingestion depends on soil adherence to skin; it is known that the adhesion process tends to exclude particles greater than 50 microm, so the fraction below this diameter would be the most dangerous for health. The aim of this work was to study the "availability", estimated by the EDTA extraction, and "oral bioaccessibility", estimated by the Simple Bioaccessibility Extraction Test (SBET), of several metals in urban soils of two European cities (Sevilla and Torino), as related to the soil particle size distribution. Torino and Sevilla showed different levels of metal contents, availability, and bioaccessibility. In Torino, the finer particles showed metal enrichment of Cu, Zn, and, to a lesser extent, Pb, whereas in Sevilla, all of the studied metals showed this enrichment compared to the whole soils. The whole soil cannot be used as a good general indicator of the bioaccessibility of metals in the finest fractions of the soil. Metal availability was higher in the clay fraction (<2 microm) than in other fractions or whole soils in both cities, and principal component analysis shows that availability is especially due to this fraction. In contrast, Cu and Pb bioaccessibility in the clay fraction seems to be slightly lower than, or comparable to, all of the other fractions and the whole soil. Bioaccessibility of Cr and Ni is clearly greater in the coarser fractions of Sevilla than those of Torino, despite the considerably greater total contents of both metals in the latter city. Adsorbed metal forms are assumed to be preferentially responsible for metals released by EDTA. A different origin is attributed to bioaccessible metal forms. Anthropic influence seems more important in determining metal availability and bioaccessibility in urban soils of both cities than the different geological or industrial characteristics.

The presence of precursors of benign pre-B lymphoblasts (hematogones) in the bone marrow of a paediatric patient with cytomegalovirus infection.

Hematogones are normal B-lymphoid precursors that multiply in the bone marrow of small children and of adults with ferropenic anaemia, neuroblastoma or idiopathic thrombocytopenic purpura. They are not normally found in peripheral blood, and the immunophenotype is virtually indistinguishable from that of B lymphoblasts. We discuss the case of a 3-month infant with an active cytomegalovirus infection, with hepatitis and pancytopenia associated with 13% hematogones in the bone marrow.

Melatonin increases following convulsive seizures may be related to its anticonvulsant properties at physiological concentrations.

Melatonin ( N-acetyl-5-methoxytryptamine, aMT) is an indoleamine produced by several organs and tissues including the pineal gland. Melatonin (aMT) modulates the activity of the brain, mainly acting on both GABA and glutamate receptors. Previous studies have shown the participation of melatonin in the control of convulsive crises, suggesting that aMT concentration increases during seizures, and that patients with seizures of diverse origins show an alteration of the aMT rhythm. However, what is not known is the duration of the aMT response to seizures, and whether aMT changes during seizures could be a marker of the disease. For this reason, the serum levels of aMT in 54 children with a convulsive crisis, febrile and epileptic, were analyzed during the crisis, as well as at 1 h and 24 hours after the seizure. The results show that aMT significantly increases during the seizure (Day group, 75.64+/-45.91 and Night group, 90.69+/-51.85 pg/mL), with normal values being recovered 1 h later (Day group, 26.33+/-10.15 and Night group, 27.78+/-7.82 pg/mL) and maintained for up to 24 hours, when the circadian variation of aMT returns to the normal acrophase. Due to the interindividual variation of aMT levels among healthy people, a single determination of the indoleamine concentration is not a suitable marker of the existence of a convulsive crisis unless the circadian profile of aMT secretion in the patient is known. The results obtained also support the view that the stimulation of aMT production by the convulsive crisis may participate in the response of the organism against the seizures.