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Paracetamol (PCT), or acetaminophen, is an important drug used worldwide for various clinical purposes. However, the excessive or indiscriminate use of PCT can provoke liver and kidney dysfunction; hence, it is essential to determine the amount of this target in biological samples. In this work, we develop a quick, simple, and sensitive voltammetric method using chemically modified electrodes to determine PCT in complex matrices, including human serum and commercial solid formulations. We modify the carbon paste electrode with stevensite monoclinic clay mineral (Stv-CPE), using cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy to characterise and detect PCT. The kinetics study provides a better electrochemical characterisation of the electrode behaviour, finding the detection and quantitation limits of 0.2 µM and 0.5 µM under favourable conditions. Further, the best linear working concentration range is 0.6-100 µM for PCT, applying the proposed method to the quantitative determination of PCT content in reference tablet formulations and biological samples for validation.

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Paracetamol (acetaminophen) (PAR), caffeine (CAF) and tramadol hydrochloride (TRA) are important drugs widely used for many clinical purposes. Determination of their contents is of the paramount interest. In this respect, a quick, simple and sensitive isocratic RP-HPLC method with photodiode array detection was developed for the determination of paracetamol, caffeine and tramadol in pharmaceutical formulations. An improved sensitive procedure was also evolved for tramadol using a fluorescence detector system. A C18 column and a mobile phase constituted by methanol/phosphate were used. LODs were found to be 0.2 µg/mL, 0.1 µg/mL and 0.3 µg/mL for paracetamol, caffeine and tramadol hydrochloride, respectively, using photodiode-array detection. Alternatively, LOD for tramadol decreased to 0.1 µg/mL with the fluorescence detector. Other notable analytical figures of merit include the linear concentration ranges, 0.8-270 µg/mL, 0.4-250 µg/mL and 1.0-300 (0.2-40) µg/mL, for the same ordered analytes (including the fluorescence detector). The proposed method was successfully applied for the quantitative determination of the three drugs in tablet dosage forms.

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Cobalt is an essential element, but its wide use in industry generates important environmental and biological problems. The present study explores theoretical and empirical models of a green process for cobalt {Co2+} bioaccumulation from aqueous solutions. Two Gram-positive Bacillus subtilis species, strains CECT 4522 and LMM (the latter a former laboratory isolate from wastewater samples, which was phylogenetically characterized for the present work), were selected among others as the best Co2+ accumulation systems. Mathematical models representing kinetic and steady-state conditions for discrete and large amounts of bacterial biomass were expanded. In this way, it was possible to theoretically calculate the amount of Co2+ retained on the outer cell wall layer and incorporated inside the cell at any time. Theoretical and empirical hyperbolic-type models were suitable to fit the experimental bioaccumulation data for discrete amounts of bacteria biomass. In addition, kinetic relationships between the amount of Co2+ accumulated and the time before (or after) reaching steady state were established for large amounts of bacterial biomass. Other kinetic approaches were also satisfactorily tested. The two Gram-positive bacteria assayed are promising agents for developing heavy metal removal systems from industrial waste.

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Two novel thoria (ThO2) nanoparticles-carbon paste electrodes were used to evaluate an anodic stripping voltammetric method for the direct determination of arsenite and total inorganic arsenic (arsenite plus arsenate) in water samples. The effect of Ag((I)), Cu((II)), Hg((II)), Sb((III)) and Se((IV)) ions on the electrochemical response of arsenic was assayed. The developed electroanalytical method offers a rapid procedure with improved analytical characteristics including good repeatability (3.4%) at low As((III)) concentrations, high selectivity, lower detection limit (0.1 µg L(-1)) and high sensitivity (0.54 µA µg(-1) L). The analytical capability of the optimized method was demonstrated by the determination of arsenic in certified reference materials (trace elements in natural water, trace elements in water and coal fly ash).

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BACKGROUND: A length polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR) is associated with both depression and hypothalamic-pituitary-adrenal (HPA) system activity. A dysregulation of the HPA system is considered to be a candidate endophenotype of depression. The objective of the present study was an investigation of a possible gene-endophenotype-interaction between 5-HTTLPR and HPA system activity in a sample of inpatients with major depression. MATERIALS AND METHODS: A total of 237 inpatients with major depression were genotyped for 5-HTTLPR and participated in a combined dexamethasone-corticotropin-releasing hormone test (Dex-CRH test) as well as using the Hamilton score (Hamilton rating scale for depression) to determine the severity of the psychopathology. RESULTS: Patients with the ss-genotype showed a significantly higher HPA -system activity in comparison to patients with the lI-genotype, but no association between 5-HTTLPR and the severity of psychopathology could be detected. CONCLUSIONS: The results of the current study demonstrate an influence of 5-HTTLPR on dysregulation of the HPA system in patients with major depression and support the hypothesis that 5-HTTLPR- and HPA-system-interaction constitutes an important component in the pathogenesis of depression.

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Epidemiological cutoff values (ECVs) for the Cryptococcus neoformans-Cryptococcus gattii species complex versus fluconazole, itraconazole, posaconazole, and voriconazole are not available. We established ECVs for these species and agents based on wild-type (WT) MIC distributions. A total of 2,985 to 5,733 CLSI MICs for C. neoformans (including isolates of molecular type VNI [MICs for 759 to 1,137 isolates] and VNII, VNIII, and VNIV [MICs for 24 to 57 isolates]) and 705 to 975 MICs for C. gattii (including 42 to 260 for VGI, VGII, VGIII, and VGIV isolates) were gathered in 15 to 24 laboratories (Europe, United States, Argentina, Australia, Brazil, Canada, Cuba, India, Mexico, and South Africa) and were aggregated for analysis. Additionally, 220 to 359 MICs measured using CLSI yeast nitrogen base (YNB) medium instead of CLSI RPMI medium for C. neoformans were evaluated. CLSI RPMI medium ECVs for distributions originating from at least three laboratories, which included ≥95% of the modeled WT population, were as follows: fluconazole, 8 µg/ml (VNI, C. gattii nontyped, VGI, VGIIa, and VGIII), 16 µg/ml (C. neoformans nontyped, VNIII, and VGIV), and 32 µg/ml (VGII); itraconazole, 0.25 µg/ml (VNI), 0.5 µg/ml (C. neoformans and C. gattii nontyped and VGI to VGIII), and 1 µg/ml (VGIV); posaconazole, 0.25 µg/ml (C. neoformans nontyped and VNI) and 0.5 µg/ml (C. gattii nontyped and VGI); and voriconazole, 0.12 µg/ml (VNIV), 0.25 µg/ml (C. neoformans and C. gattii nontyped, VNI, VNIII, VGII, and VGIIa,), and 0.5 µg/ml (VGI). The number of laboratories contributing data for other molecular types was too low to ascertain that the differences were due to factors other than assay variation. In the absence of clinical breakpoints, our ECVs may aid in the detection of isolates with acquired resistance mechanisms and should be listed in the revised CLSI M27-A3 and CLSI M27-S3 documents.

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BACKGROUND: Some molecular features of meticillin-resistant Staphylococcus aureus (MRSA) isolates causing invasive infections have been shown to have clinical implications. There is a need to monitor the situation using a combination of molecular and clinical data because, although MRSA clones tend to predominate over wide geographical areas, clonal shifts may take place. AIM: To study the epidemiological features and perform molecular characterization of a retrospective cohort of 98 cases of nosocomial and healthcare-associated MRSA bacteraemia in 10 hospitals in Andalusia, Spain. METHODS: Relatedness of isolates was investigated using pulsed-field gel electrophoresis (PFGE), S. aureus protein A (spa) typing and clonal complex (CC) assignment. Staphylococcal chromosomal cassette mec (SCCmec) type and accessory gene regulator (agr) group were studied by polymerase chain reaction. agr function was assessed. RESULTS: Most isolates were CC5, SCCmec type IV and agr group II. The most common spa type was t067. Six major clusters were identified by PFGE. Six small clusters of epidemiologically related cases sharing isolates from the same PFGE subtype were identified. Five percent of isolates had a vancomycin minimum inhibitory concentration (MIC) of 2 µg/mL on broth microdilution, although 44% had an MIC >1 µg/mL on E-test. Variables independently associated with MIC >1 mg/L on E-test were surgery during present admission and Charlson index ≥2. CONCLUSION: A specific CC that has been predominant in Spain over the last decade caused most of the cases in this study. PFGE was more discriminatory than spa typing in showing clusters of epidemiologically related cases. Some patient features were associated with vancomycin MIC >1 mg/L on E-test.

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A novel method for the retention of arsenate [As(V)] combining time-controlled solid-phase extraction with living bacterial biomass is presented. As(V) retention was carried out by exposing the extractant, consisting of a living double-mutant of Corynebacterium glutamicum strain ArsC1-C2, to the sample for a retention time of 1-7min, before the arsenic distribution equilibrium between the sample solution and the extractant was established. The amount of As(V) retained in the biomass was measured by inductively coupled plasma-mass spectrometry (ICP-MS) after the sample had been treated with nitric acid. A theoretical model of the retention process was developed to describe the experimental retention-time profiles obtained with the bacterial cells. This relationship provided a feasible quantification of the retention process before steady-state was reached, providing that the agitation conditions and the retention time had been controlled. An analytical procedure for the retention/quantification of As(V) was then developed; the detection limit was 0.1 ng As(V)mL(-1) and the relative standard deviation 2.4-3.0%. The maximum effective retention capacity for As(V) was about 12.5mgAs(g biomass)(-1). The developed procedure was applied to the determination of total arsenic in coal fly ash, using a sample that had undergone oxidative pre-treatment.

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This study aimed at confirming the increased growth inhibition (GI) of human prostate tumors produced by a intentionally palliative combination treatment of cryochemotherapy, i.e., partial cryoablation (CA) followed by intratumor partial chemotherapy with injection of microencapsulated 5-fluorouracil (MCC/5FU) at the ice ball (IB) periphery. We report the local effectiveness of cryochemotherapy compared to chemotherapy only with using multiple injections of MCC/5FU spaced out to maximize cumulative effect of sustained release of 5-fluorouracil (5FU) during a 21-day period. Prostate bioluminescent tumor cells - DU145 Luc+ - were implanted sub-cutaneously and bilaterally in each flank of nude mice. Tumors were treated with: (i) cryoablation alone (CA), causing necrosis in approximately 45% of the tumor volume; (ii) cryo-chemotherapy (CA+MCC/5FU), a combined regimen consisting of partial CA followed immediately and on day 14 by ultrasound assisted, intra-tumor injections (40 mul) of MCC/5FU( 0.81 ng/mm3 of tumor) containing Ethiodol (IPO) an imaging contrast agent, on two opposite sides of the unfrozen part of tumor; (iii) intratumor chemotherapy (MCC/5FU), consisting of three successive intra-tumor injections of microencapsulated 5FU on two opposite sides on Day 0, 4, and 11, and (iv) control series (MM), consisting of a single injection of echogenic microcapsules (mucaps) containing IPO but no 5FU. Tumor growth and viability were followed during a 21-day period with using biometric measurements, bioluminescent imaging (BLI) and ultrasonography (US), and then animals were sacrificed. CA, spared 54.4% of the tumor volume and the IB kill ratio was 0.4 +/-0.9. The maximum tumor volume reduction observed by Day 3 was short-lived as re-growth became significant by Day 6. CA+ MCC/5FU spared 55.6% of the tumor volume and the IB kill ratio was 0.54 +/- 0.12. The viable tumor cells, as measured by BLI remained at preoperative levels. After 11 days CA+ MCC/5FU limited the growth of the partially ablated tumors to only 10.6% of the growth of CA treated tumors (p=0.04). By Day 18 the CA+MCC/5FU had inhibited tumor growth by 78% compared to the CA treated tumors (p=0.05) and after 21 days the growth was inhibited by 71% (p=0.04) compared to more than 650% growth in the MM group and 600% growth in the CA treated group. The two injections of MCC/5FU produced a visible focal necrosis in 55% of the tumors. MCC/5FU proved effective by themselves and reduced the growth of prostate tumor volumes by 51% (p=0.025) compared to MM controls during the 21 days. Focal necrosis was macroscopically visible at the site of 66% of the tumors injected only with MCC/5FU. The BLI clearly showed zones of reduced tumor cell viability at the injection sites. The mean number of bioluminescent (viable) tumor cells, remained below preoperative levels for the first 6 days and then increased at a rate approximately 20% that of the growth of control tumor cells. The chemoablative effects of intentionally limited doses of MCC/5FU injected within the IB margin augment the effects of incomplete cryoablation in this prostate tumor model, with dramatic tumor GI and directionally increased necrosis dimensions compared to CA alone, confirming the results of a previous study. Our results indicate the potential advantages of our combination cryochemotherapy that utilizes different mechanisms to kill tumor cells and retard tumor growth in the region surrounding the IB where tumor cells escape the lethal effects of cryosurgery. The study suggests that cryochemotherapy may become a more predictable technique that could be indicated as an adjuvant or an alternative to palliative therapy of hormone refractory prostate cancer (HRPC).

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Electrothermal atomization of beryllium from graphite and tungsten surfaces was compared with and without the use of various chemical modifiers. Tungsten proved to be the best substrate, giving the more sensitive integrated atomic absorption signals of beryllium. Tungsten platform atomization with zirconium as a chemical modifier was used for the determination of beryllium in several NIST SRM certified reference samples, with good agreement obtained between the results found and the certified values. The precision of the measurements (at 10 microgL(-1)), the limit of detection (3sigma), and the characteristic mass of beryllium were 2.50%, 0.009 microgL(-1) and 0.42 pg, respectively.

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OBJECTIVES: BAL 4815 is a new antifungal drug and it is the active component of the antifungal triazole BAL 8557 (the water-soluble precursor). We studied the in vitro fungistatic and fungicidal activities of BAL 4815 against 103 clinical isolates of filamentous fungi, including 51 isolates of Aspergillus spp. and 52 isolates of non-Aspergillus filamentous fungi. METHODS: We evaluated the in vitro activity of BAL 4815 against 51 isolates of Aspergillus spp., 20 isolates of dematiaceous fungi, 18 isolates of hyaline Hyphomycetes and 14 isolates of Zygomycetes. MICs were determined following the CLSI M38-A broth microdilution method, using RPMI 1640 medium buffered to pH 7.0 with MOPS. Microdilution plates were incubated at 35 degrees C and read at 24 and 48 h (Mucorales were read at 24 h). Minimal fungicidal concentrations were also determined. RESULTS: For all isolates, geometric mean MICs, MIC(50)s, MIC(90)s and MIC ranges (mg/L) were: Aspergillus spp., 1.67, 2, 4 and 0.5-4; dematiaceous fungi, 1.62, 1, >8 and 0.03 to >8; hyaline Hyphomycetes, 2.41, 2, >8 and 0.03 to >8; and Zygomycetes, 6.81, 8, >8 and 0.03 to >8. Differences in susceptibility between genera were noted. Scedosporium prolificans, Fusarium spp., Mucor spp. and Rhizopus spp. (MIC(90) > 8 mg/L) were less susceptible than Aspergillus spp. (MIC(90) = 4 mg/L). CONCLUSIONS: BAL 4815 has excellent in vitro activity against Aspergillus spp. and variable activity against other filamentous fungi.

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The antifungal drug susceptibility of 70 Cryptococcus neoformans isolates obtained in Spain from 1994 to 1996 (23 isolates) and from 1997 to 2005 (47 isolates) was investigated. The MICs of fluconazole, itraconazole and voriconazole were determined by the modified Clinical and Laboratory Standards Institute (CLSI; formerly National Committee for Clinical Laboratory Standards) broth microdilution method. The MIC(50) and MIC(90) for itraconazole and voriconazole did not change significantly from 1994 to 2005. The MIC(50) of fluconazole remained stable and the MIC(90) decreased by 2 log(2) dilution in the isolates collected from 1997 to 2005. We conclude that the in vitro resistance to fluconazole decreased over an 11-year period. In addition, a tendency for the development of possible cross-resistance between the three triazoles was observed.

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The natural resistance mechanisms of corynebacteria to respond to the environments containing high levels of arsenic were successfully adopted to develop inexpensive and selective extractants for submicrogram amounts of arsenic. Kinetic and equilibrium characteristics were evaluated, and a preliminary exploration of the capability of these strains to be used for arsenic speciation was also made in this work. Three kinetics models were used to fit the experimental data. It was found that the pseudo-first-order kinetics model was not quite adequate to describe the retention process, while the intraparticle diffusion and the pseudo-second-order kinetics models provide the best fits. The equilibrium isotherm showed that the retention of arsenic was consistent with the Langmuir equation and that the Freundlich and Dubinin-Radushkevich models provided poorer fits to the experimental data. The maximum effective retention capacity for arsenic was about 15.4 ng As/mg biomass. The amount of arsenic retained was directly measured in the biomass by forward planning a slurry electrothermal atomic absorption spectrometric procedure.

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The disk diffusion method was evaluated for determining posaconazole susceptibility against 78 strains of molds using two culture media in comparison with the CLSI (Clinical Laboratory Standards Institute) broth microdilution method (M38-A). A significant correlation between disk diffusion and microdilution methods was observed with both culture media.

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The aim of this study was to establish the degree of stabilization of sludge and its influence on the evolution of total aerobic micro-organisms and those of faecal origin when the sludge is applied to soil. Two different sludges were used, from a food industry (D) and from an urban treatment plant, (E). Both sludges were stabilized aerobically in laboratory conditions. The stabilization process was monitored by following the evolution of pathogenic micro-organisms and the content of total solids and volatile matter in suspension, while on the other hand the microbial evolution of the samples of soil plus sludge and control soil (S) were monitored over an incubation period of 80 days. After 20 or 40 days of incubation, in both sludge treatments the populations of pathogenic micro-organisms of faecal origin were below detectable limits, regardless of the degree of stabilization of the sludge. Soil without sludge treatment did not show pathogenic micro-organisms.

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A study was made of the influence of the application of sewage sludge on the degradation of pesticides in the soil. Two kinds of sludge were used, with different characteristics, one from an urban treatment plant and one from a food processing plant. Three organophosphorus insecticides, fenitrothion, diazinon and dimethoate, were studied. The relative importance was determined of the chemical and biological degradation processes, which involved experiments on soil and sterile soil samples. A comparative study was also made of the degradation of pesticide residues and the evolution of the microbial population. The application of sludge seems to have a complex effect on the degradation of pesticides, determined by the bioavailability and biodegradability of their active ingredient. The biodegradation of pesticide residues brings about alterations in the microorganism population of the soil.

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UNLABELLED: A study of the interactions of several selenium species with living bacterial cells was carried out by Fourier-transform infrared (FT-IR) spectroscopy. Bacterial cells consisted of an Escherichia coli strain (K-12) cultivated in a growth medium based on glucose contaminated with selenium species. Equilibrium between the analyte in the solution and the extraction medium was established, and then the effects of selenium species upon the external membrane of the living bacterial cells were characterized by performing FT-IR spectroscopy of whole cells. The presence of the toxicants at various concentrations in the culture medium had an effect on the FT-IR spectra, and the concentration of the selenium species was determined directly in the biomass by FT-IR spectroscopy. The intensity ratios between several absorption lines, which varied as a function of the concentration of the selenium species, were used as the analytical signal. ELECTRONIC SUPPLEMENTARY MATERIAL: Supplementary material is available for this article if you access the article at http://dx.doi.org/10.1007/s00216-004-2494-4. A link in the frame on the left on that page takes you directly to the supplementary material.

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We monitored the effect of the application of treated sludge on the behaviour of enterobacteriaceae (mainly faecal coliforms and especially Escherichia coli) in the soil, and studied their evolution over time after application. Three different sludges were used: two from a municipal sewage plant, one of them had been subjected to anaerobic digestion and heat drying, and the other to anaerobic digestion and mechanical dehydration, and one from a dairy waste treatment to aerobic digestion and gravity thickening. Two types of tests were carried out: type O, in the open air, with no possibility of controlling humidity or temperature; and type L, under laboratory conditions, with controlled temperature and humidity. Sludge tests were also run on unscreened soil previously treated with chemical fertilizer. After 80 days of experimentation the populations of faecal coliforms and E. coli had decreased considerably or were undetectable in assays carried out on the soil/sludge mixtures, under both open-air and laboratory conditions, but that, over the same period, in the mixtures containing chemical fertilizer (calcium ammonium nitrate) there had been a considerable increase in the micro-organism populations studied.

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A systematic study of the efficiency of protons, Ni, Pd and Th as chemical modifiers for the determination of cadmium by electrothermal atomic absorption spectrometry (ETAAS) using fast temperature programs was made for platform atomization. A comparison was made in terms of the salt type, absorbance-time profiles and elimination of the sodium chloride interference. The results were adapted to develop a method for the ETAAS determination of cadmium in biological and environmental samples. The highest sensitivity to determine cadmium in biological and environmental samples was obtained using nickel (together with protons) as a chemical modifier. The accuracy of the method was tested by the determination of cadmium in different certified reference materials. The best detection limit and the characteristic mass of Cd were found to be 0.03 ng mL(-1) and 0.35 pg, respectively.

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