Coupling membrane separation and photocatalytic oxidation processes for the degradation of pharmaceutical pollutants.

The coupling of membrane separation and photocatalytic oxidation has been studied for the removal of pharmaceutical pollutants. The retention properties of two different membranes (nanofiltration and reverse osmosis) were assessed. Comparable selectivity on the separation of pharmaceuticals were observed for both membranes, obtaining a permeate stream with concentrations of each pharmaceutical below 0.5 mg L(-)(1) and a rejected flux highly concentrated (in the range of 16-25 mg L(-)(1) and 18-32 mg L(-)(1) of each pharmaceutical for NF-90 and BW-30 membranes, respectively), when an initial stream of six pharmaceuticals was feeding to the membrane system (10 mg L(-)(1) of each pharmaceutical). The abatement of concentrated pharmaceuticals of the rejected stream was evaluated by means of heterogeneous photocatalytic oxidation using TiO2 and Fe2O3/SBA-15 in presence of hydrogen peroxide as photo-Fenton system. Both photocatalytic treatments showed remarkable removals of pharmaceutical compounds, achieving values between 80 and 100%. The nicotine was the most refractory pollutant of all the studied pharmaceuticals. Photo-Fenton treatment seems to be more effective than TiO2 photocatalysis, as high mineralization degree and increased nicotine removal were attested. This work can be considered an interesting approach of coupling membrane separation and heterogeneous photocatalytic technologies for the successful abatement of pharmaceutical compounds in effluents of wastewater treatment plants.

Progress in stem cell therapy for major human neurological disorders.

Human neurological disorders such as Alzheimer's disease (AD), Parkinson's disease, stroke or spinal cord injury are caused by the loss of neurons and glial cells in the brain or spinal cord in the Central Nervous System (CNS). Stem cell technology has become an attractive option to investigate and treat these diseases. Several types of neurons and glial cells have successfully been generated from stem cells, which in some cases, have ameliorated some dysfunctions both in animal models of neurological disorders and in patients at clinical level. Stem cell-based therapies can be beneficial by acting through several mechanisms such as cell replacement, modulation of inflammation and trophic actions. Here we review recent and current remarkable clinical studies involving stem cell-based therapy for AD and stroke and provide an overview of the different types of stem cells available nowadays, their main properties and how they are developing as a possible therapy for neurological disorders.

Evaluation of two commercial enzyme immunoassays for the detection of norovirus in faecal samples from hospitalised children with sporadic acute gastroenteritis.

Two commercially available enzyme immunoassays (EIAs), IDEIA and Ridascreen, for norovirus antigen detection were evaluated with 117 faecal samples from hospitalised children with acute gastroenteritis. Eighteen of 39 samples positive by RT-PCR were characterised by sequence analysis, and 17 of these were related to norovirus genogroup II. When compared with RT-PCR, the sensitivity and specificity values were 76.9% and 85.9%, respectively, for the IDEIA assay, and 59.0% and 73.1%, respectively, for the Ridascreen assay. The sensitivity and specificity of both EIA tests require improvement, but they could both eventually be of use in the diagnosis of norovirus diarrhoea in clinical laboratories.

Validation of a capillary zone electrophoresis method for determination of rimantadine hydrochloride in Rimantadin100 tablets and the method application to dissolution test monitoring.

A capillary zone electrophoretic method with indirect UV-detection for determination of rimantadine, an antiviral drug against influenza A, in tablets was validated. Instrumental precision, the method precision, accuracy, calibration curve linearity, selectivity, robustness, and time stability of the sample and the standard were tested. The method was also applied to monitor dissolution tests of the tablets. The possibility of addition of an internal standard for improvement of the method precision was discussed.

[Sinusitis in immunocompromised patients. A multicenter study]. / Sinusitis en inmunodeprimidos. Un estudio multicéntrico.

This paper evaluates different aspects of sinusitis in patients with a decreased immunological system, such as its prevalence and clinical evolution, its peculiar bacteriology and the altered response to treatment, and the prognosis, especially in patients with AIDS. There seems to be an increased prevalence of sinusitis in these patients, with a relationship between their immunological status and the severity and aggressiveness of the sinusitis. Bacteriological studies reveal the pressure of more aggressive species, such as P. aeruginosa, and specific sinusitis are more frequent, which may explain why the treatment with common antibiotics often remains uneffective. The simultaneous therapy of concomitant infections leads to a higher resistance towards common drugs. A standard treatment is therefore needed. The results of three studies, retrospective and prospective, on HIV-infected patients reveal a high incidence of acute sinusitis with aggressive bacteria.

High-performance liquid chromatographic determination of deoxycytidine monophosphate and methyldeoxycytidine monophosphate for DNA demethylation monitoring: experimental design and artificial neural networks optimisation.

The optimal conditions for the separation of 2'-deoxycytidine-5'-monophosphate and 5-methyl-2'-deoxycytidine-5'-moncphosphate in the matrix of other natural occurring nucleotides after digest of DNA were investigated. Using experimental design combined with artificial neural networks, efficient optimisation of the HPLC separation conditions was performed. The mobile phase composition was optimised on the basis of its three components (concentration of phosphate, content of methanol and pH). The best separation was obtained with a mobile phase containing 50 mM phosphate, pH 5.5 and 6% methanol. The final resolution achieved between 2'-deoxycytidine-5'-monophosphate and 5-methyl-2'-deoxycytidine-5'-monophosphate was equal to 2.78. Finally, the optimised system was successfully tested on the nucleotide mixture solution to determine the methylation state of 2'-deoxycytidine-5'-monophosphate in DNA in the search for FMR1 gene changes.

Molecular determinants of membrane potential dependence in vertebrate gap junction channels.

The conductance, g(j), of many gap junctions depends on voltage between the coupled cells (transjunctional voltage, V(j)) with little effect of the absolute membrane potential (V(m)) in the two cells; others show combined V(j) and V(m) dependence. We examined the molecular determinants of V(m) dependence by using rat connexin 43 expressed in paired Xenopus oocytes. These junctions have, in addition to V(j) dependence, V(m) dependence such that equal depolarization of both cells decreases g(j). The dependence of g(j) on V(m) was abolished by truncation of the C-terminal domain (CT) at residue 242 but not at 257. There are two charged residues between 242 and 257. In full-length Cx43, mutations neutralizing either one of these charges, Arg243Gln and Asp245Gln, decreased and increased V(m) dependence, respectively, suggesting that these residues are part of the V(m) sensor. Mutating both residues together abolished V(m) dependence, although there is no net change in charge. The neutralizing mutations, together or separately, had no effect on V(j) dependence. Thus, the voltage sensors must differ. However, V(j) gating was somewhat modulated by V(m), and V(m) gating was reduced when the V(j) gate was closed. These data suggest that the two forms of voltage dependence are mediated by separate but interacting domains.

Separation of polyphenols in Canary Islands wine by capillary zone electrophoresis without preconcentration.

A method for separation and determination of polyphenols in wine by capillary zone electrophoresis (CZE) without any preconcentration step is described. The sensitivity and limits of detection for gentisic and p-coumaric acid are better than those previously published. The effect of a possible C18 solid-phase extraction prior to the CZE analysis was examined. The developed optimized method (without any extraction step) was applied to the analysis of wines from Tenerife, Canary Islands.

Molecular dissection of transjunctional voltage dependence in the connexin-32 and connexin-43 junctions.

Most gap junction channels are sensitive to the voltage difference between the two cellular interiors, termed the transjunctional voltage (V(j)). In several junctions, the conductance transitions induced by V(j) show more than one kinetic component. To elucidate the structural basis of the fast and slow components that characterize the V(j )dependence of connexin-32 (Cx32) and connexin-43 (Cx43) junctions, we created deletions of both connexins, where most of the carboxy-terminal (CT) domain was removed. The wild-type and "tailless" mutants were expressed in paired Xenopus oocytes, and the macroscopic gating properties were analyzed using the dual voltage clamp technique. Truncation of the CT domain of Cx32 and Cx43 abolished the fast mechanism of conductance transitions and induced novel gating properties largely attributable to the slow mechanism of gating. The formation of hybrid junctions comprising wild-type and truncated hemichannels allowed us to infer that the fast and slow components of gating reside in each hemichannel and that both gates close at a negative V(j) on the cytoplasmic side. Thus we conclude that the two kinetic components of V(j)-sensitive conductance are a result of the action of two different gating mechanisms. They constitute separate structures in the Cx32 and Cx43 molecules, the CT domain being an integral part of fast V(j) gating.

Capillary zone electrophoresis determination of galanthamine in biological fluids and pharmaceutical preparatives: experimental design and artificial neural network optimization.

Galanthamine is a third-generation cholinesterase inhibitor used against Alzheimer's disease. New analytical methods for the determination of galanthamine in pharmaceutical preparatives and biological fluids, such as urine and serum, were developed. An experimental design and artificial neural network approach were used for method optimization. Thirty-five ppb of galanthamine were determined in serum samples (with addition of 10 mM magnesium chloride and using solid-phase preconcentration).

Capillary electrophoresis separation of the new anti-AIDS agents 9-(2-phosphonylmethoxyethyl)adenine and 9-(2-phosphonylmethoxyethyl)-2,6-diaminopurine in mixtures with some monoribonucleotides or the most common deoxynucleotides.

The present work describes an electrophoretic method for the separation and determination of the new antivirals, 9-(2-phosphonylmethoxyethyl)adenine (PMEA) and 9-(2-phosphonylmethoxyethyl)-2,9-diaminopurine (PMEDAP) in model mixtures with some monoribonucleotide isomers (3'-AMP, 2'-CMP, 3'-CMP, 3'-GMP, 2'-GMP, 3'-UMP, 5'-GMP, and 5'-UMP) or with the most common deoxynucleotides (dCMP, dCDP, dCTP, dTMP, dTDP, dTTP, dGMP, dGDP, dGTP, dAMP, dADP, dATP). A fused-silica capillary tube, 75 microm ID, 67.8 cm total length (60.3 cm length to the detector), with detection at 210 nm was employed. A hydrodynamic injection for 10 s (1.5 psi vacuum) was utilized to introduce the sample, and 30 kV voltage was applied for the separation. The complete separation of PMEA and PMEDAP from the mononucleotide isomers and deoxynucleotide mixtures is possible in less that 10 min and 25 min, respectively, using 20 mM borate buffer, pH 9.9, with the addition of 10 mM beta-cyclodextrin. Efficiencies of more than 120 000 and resolution higher than 1.9 were reached for each of the compounds studied. This capillary electrophoretic procedure opens the possibility for future determination of PMEA and PMEDAP in cell pool samples.

Assembly of chimeric connexin-aequorin proteins into functional gap junction channels. Reporting intracellular and plasma membrane calcium environments.

Chimeric proteins comprising connexins 26, 32, and 43 and aequorin, a chemiluminescent calcium indicator, were made by fusing the amino terminus of aequorin to the carboxyl terminus of connexins. The retention of function by the chimeric partners was investigated. Connexin 32-aequorin and connexin 43-aequorin retained chemiluminescent activity whereas that of connexin 26-aequorin was negligible. Immunofluorescent staining of COS-7 cells expressing the chimerae showed they were targeted to the plasma membrane. Gap junction intercellular channel formation by the chimerae alone and in combination with wild-type connexins was investigated. Stable HeLa cells expressing connexin 43-aequorin were functional, as demonstrated by Lucifer yellow transfer. Paris of Xenopus oocytes expressing connexin 43-aequorin were electrophysiologically coupled, but those expressing chimeric connexin 26 or 32 showed no detectable levels of coupling. The formation of heteromeric channels constructed of chimeric connexin 32 or connexin 43 and the respective wild-type connexins was inferred from the novel voltage gating properties of the junctional conductance. The results show that the preservation of function by each partner of the chimeric protein is dictated mainly by the nature of the connexin, especially the length of the cytoplasmic carboxyl-terminal domain. The aequorin partner of the connexin 43 chimera reported calcium levels in COS-7 cells in at least two different calcium environments.

Characterization of a sapphire-epoxy coating for capillary electrophoresis.

A new procedure for coating capillaries for capillary electrophoresis applying a sapphire (alumina) containing epoxy resin was developed. Coated capillaries showed considerably reduced electroosmotic flow, and decreased the adsorption of proteins to the internal wall of the capillary. Coating is transparent down to 195 nm and can be used with advantage to analyze different kinds of substances, such as small cations and/or anions, and proteins.

Species-specific voltage-gating properties of connexin-45 junctions expressed in Xenopus oocytes.

Gap junctions composed of connexin-45 (Cx45) homologs from four species, zebrafish, chicken, mouse, and human, were expressed in pairs of Xenopus oocytes. The macroscopic conductance (gj) of all Cx45 junctions was modulated by transjunctional voltage (Vj) and by the inside-outside voltage (Vm), and the modulation was species specific. Although their gating characteristics varied in voltage sensitivity and kinetics, the four Cx45 junctions shared 1) maximum conductance at Vj = 0 and symmetrical gj reduction in response to positive and negative Vj of low amplitude, with little residual conductance; and 2) gj increases in response to simultaneous depolarization of the paired cells. The formation of hybrid channels, comprising Cx45 hemichannels from different species, allowed us to infer that two separate gates exist, one in each hemichannel, and that each Cx45 hemichannel is closed by the negativity of Vj on its cytoplasmic side. Interestingly, the Vm dependence of hybrid channels also suggests the presence of two gates in series, one Vm gate in each hemichannel. Thus the Vj and Vm dependence provides evidence that two independent voltage gates in each Cx45 hemichannel exist, reacting through specific voltage sensors and operating by different mechanisms, properties that have evolved divergently among species.

Efficacy and safety of imipenem/cilastatin in the empirical treatment of septicemia.

The clinical efficacy and safety of imipenem/cilastatin in the empirical treatment of adult non-immunocompromised patients with severe bacterial septicemia was studied in a prospective and open trial. The dosage of imipenem/cilastatin was 500 mg q 6 h. Of 58 patients included, 41 were evaluable for efficacy. In those patients, 35 had chronic underlying diseases and the foci of bacteremia were identified in 37; the most common ones being cardiovascular, urologic or intraabdominal infections. All isolated organisms were sensitive to imipenem with an MIC for 90% of the strains of 1 mg/l. Imipenem/cilastatin treatment resulted in rapid control of the infections in 39 of the 41 evaluable patients (95.5%). In the remaining two patients treatment had to be prematurely discontinued due to adverse effects. The causative bacterial strains were eradicated from blood in all patients who received more than one day of imipenem/cilastatin treatment but persisted sensitive to imipenem in peripheral foci in five patients (17%). Clinical and laboratory adverse reactions were noted in seven patients. In conclusion, imipenem/cilastatin was a well tolerated and effective empirical drug for treatment of septicemia.