Development of albendazole sulfoxide-loaded Eudragit microparticles: A potential strategy to improve the drug bioavailability

Albendazole sulfoxide (ABZSO), a broad spectrum anthelmintic drug extensively used in veterinary medicine, exhibits a low and erratic bioavailability due to its poor solubility in biological fluids. The aims of this study were the development, physicochemical characterization, and in vitro release profile evaluation of ABZSO-loaded Eudragit RS PO (R) microparticles (MPs) in order to improve the rate of dissolution and the dissolved percentage of the drug in pH 7.4. MPs were successfully obtained by the emulsification/solvent evaporation method, achieving entrapment efficiency and process yield of about 60% and mean size of 254 nm. The in vitro release profile study showed that dissolution of ABZSO followed a pseudo-second order kinetics and MPs were able to increase significantly (p < 0.05) the rate of dissolution of ABZSO compared to the micronized and non-micronized free drug, what could lead to an improvement in bioavailability and, consequently, in the antiparasitic activity. (C) 2011 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.

Blocking of Connexin-Mediated Communication Promotes Neuroprotection during Acute Degeneration Induced by Mechanical Trauma

Accruing evidence indicates that connexin (Cx) channels in the gap junctions (GJ) are involved in neurodegeneration after injury. However, studies using KO animal models endowed apparently contradictory results in relation to the role of coupling in neuroprotection. We analyzed the role of Cx-mediated communication in a focal lesion induced by mechanical trauma of the retina, a model that allows spatial and temporal definition of the lesion with high reproducibility, permitting visualization of the focus, penumbra and adjacent areas. Cx36 and Cx43 exhibited distinct gene expression and protein levels throughout the neurodegeneration progress. Cx36 was observed close to TUNEL-positive nuclei, revealing the presence of this protein surrounding apoptotic cells. The functional role of cell coupling was assessed employing GJ blockers and openers combined with lactate dehydrogenase (LDH) assay, a direct method for evaluating cell death/viability. Carbenoxolone (CBX), a broad-spectrum GJ blocker, reduced LDH release after 4 hours, whereas quinine, a Cx36-channel specific blocker, decreased LDH release as early as 1 hour after lesion. Furthermore, analysis of dying cell distribution confirmed that the use of GJ blockers reduced apoptosis spread. Accordingly, blockade of GJ communication during neurodegeneration with quinine, but not CBX, caused downregulation of initial and effector caspases. To summarize, we observed specific changes in Cx gene expression and protein distribution during the progress of retinal degeneration, indicating the participation of these elements in acute neurodegeneration processes. More importantly, our results revealed that direct control of GJ channels permeability may take part in reliable neuroprotection strategies aimed to rapid, fast treatment of mechanical trauma in the retina.

Low polymorphism revealed in new microsatellite markers for Bemisia tabaci (Hemiptera: Aleyrodidae)

The silverleaf whitefly (Bemisia tabaci) is actually a complex of morphologically indistinct species that vary in their capacity to transmit plant viruses and to induce physiological disorders in plants of economic importance. The worldwide impact of this whitefly has increased greatly, as it is a vector of various types of phytovirus, especially geminiviruses, in plants of economic importance. The adaptability of B. tabaci to many regions of the world has fostered the appearance of various biotypes that attack a broad spectrum of host plants. We developed microsatellite markers to study genetic variability and population structure of this whitefly in Brazil. Thirteen polymorphic microsatellite markers were isolated and characterized in 20 individuals from a natural population that were collected in soybean in Campinas (SP). The number of alleles per locus ranged from one to two, and the expected heterozygosity ranged from 0.000 to 0.505. These microsatellite markers will be useful for studies and management of B. tabaci. The low polymorphism found in these molecular markers is probably associated with homology of genes expressed in these markers.

In vivo hydroquinone exposure impairs MCP-1 secretion and monocyte recruitment into the inflamed lung

Alveolar macrophages (AMs) are important cells in the resolution of the inflammatory process and they come into direct contact with inhaled pollutants. Hydroquinone (HQ) is an environmental pollutant and a component of cigarette smoke that causes immunosuppressive effects. In the present work, we showed that mice exposed to low levels of aerosolized HQ (25 ppm; 1 h/day/5 days) presented impaired mononuclear cell migration to the lipopolysaccharide (LPS)-inflamed lung. This may have been due to reduced monocyte chemoattractant protein-1 (MCP-1) secretion into bronchoalveolar lavage fluid (BALF), and it was not related to alterations to mononuclear cell mobilization into the blood or adhesion molecules expression on mononuclear cell membranes. Corroborating the actions of HQ on MCP-1 secretion, reduced MCP-1 concentrations were also found in the supernatant of ex vivo AM and tracheal tissue collected from HQ-exposed mice. A direct action of HQ on MCP-1 secretion, resulting from impaired gene synthesis, was verified by in vitro incubation of naive AMs or tracheal tissue with HQ. The role of reduced levels of MCP-1 in the BALF on monocyte migration was analysed in the human monocytic lineage THP-1 in in vitro chemotaxis assays, which showed that the reduced concentrations of MCP-1 found in the BALF or cell supernatants from HQ-exposed mice impaired cell migration. Considering the fact that MCP-1 presents a broad spectrum of actions on pathophysiological conditions and that resident mononuclear cells are involved in lung tissue homeostasis and in immune host defence, the mechanism of HQ toxicity presented herein might be relevant to the genesis of infectious lung diseases in smokers and in inhabitants of polluted areas. (C) 2012 Elsevier Ireland Ltd. All rights reserved.

Aerosol profiling with lidar in the Amazon Basin during the wet and dry season

For the first time, multiwavelength polarization Raman lidar observations of optical and microphysical particle properties over the Amazon Basin are presented. The fully automated advanced Raman lidar was deployed 60 km north of Manaus, Brazil (2.5 degrees S, 60 degrees W) in the Amazon rain forest from January to November 2008. The measurements thus cover both the wet season (Dec-June) and the dry or burning season (July-Nov). Two cases studies of young and aged smoke plumes are discussed in terms of spectrally resolved optical properties (355, 532, and 1064 nm) and further lidar products such as particle effective radius and single-scattering albedo. These measurement examples confirm that biomass burning aerosols show a broad spectrum of optical, microphysical, and chemical properties. The statistical analysis of the entire measurement period revealed strong differences between the pristine wet and the polluted dry season. African smoke and dust advection frequently interrupt the pristine phases during the wet season. Compared to pristine wet season conditions, the particle scattering coefficients in the lowermost 2 km of the atmosphere were found to be enhanced, on average, by a factor of 4 during periods of African aerosol intrusion and by a factor of 6 during the dry (burning) season. Under pristine conditions, the particle extinction coefficients and optical depth for 532 nm wavelength were frequently as low as 10-30 Mm(-1) and <0.05, respectively. During the dry season, biomass burning smoke plumes reached to 3-5 km height and caused a mean optical depth at 532 nm of 0.26. On average during that season, particle extinction coefficients (532 nm) were of the order of 100 Mm(-1) in the main pollution layer (up to 2 km height). Angstrom exponents were mainly between 1.0 and 1.5, and the majority of the observed lidar ratios were between 50-80 sr.

Therapeutic use of a cationic antimicrobial peptide from the spider Acanthoscurria gomesiana in the control of experimental candidiasis

Background: Antimicrobial peptides are present in animals, plants and microorganisms and play a fundamental role in the innate immune response. Gomesin is a cationic antimicrobial peptide purified from haemocytes of the spider Acanthoscurria gomesiana. It has a broad-spectrum of activity against bacteria, fungi, protozoa and tumour cells. Candida albicans is a commensal yeast that is part of the human microbiota. However, in immunocompromised patients, this fungus may cause skin, mucosal or systemic infections. The typical treatment for this mycosis comprises three major categories of antifungal drugs: polyenes, azoles and echinocandins; however cases of resistance to these drugs are frequently reported. With the emergence of microorganisms that are resistant to conventional antibiotics, the development of alternative treatments for candidiasis is important. In this study, we evaluate the efficacy of gomesin treatment on disseminated and vaginal candidiasis as well as its toxicity and biodistribution. Results: Treatment with gomesin effectively reduced Candida albicans in the kidneys, spleen, liver and vagina of infected mice. The biodistribution of gomesin labelled with technetium-99 m showed that the peptide is captured in the kidneys, spleen and liver. Enhanced production of TNF-alpha, IFN-gamma and IL-6 was detected in infected mice treated with gomesin, suggesting an immunomodulatory activity. Moreover, immunosuppressed and C. albicans-infected mice showed an increase in survival after treatment with gomesin and fluconazole. Systemic administration of gomesin was also not toxic to the mice Conclusions: Gomesin proved to be effective against experimental Candida albicans infection. It can be used as an alternative therapy for candidiasis, either alone or in combination with fluconazole. Gomesin's mechanism is not fully understood, but we hypothesise that the peptide acts through the permeabilisation of the yeast membrane leading to death and/or releasing the yeast antigens that trigger the host immune response against infection. Therefore, data presented in this study reinforces the potential of gomesin as a therapeutic antifungal agent in both humans and animals.

Fumarate hydratase isoforms of Leishmania major: Subcellular localization, structural and kinetic properties

Fumarate hydratases (FHs; EC 4.2.1.2) are enzymes that catalyze the reversible hydration of fumarate to S-malate. Parasitic protists that belong to the genus Leishmania and are responsible for a complex of vector-borne diseases named leishmaniases possess two genes that encode distinct putative FH enzymes. Genome sequence analysis of Leishmania major Friedlin reveals the existence of genes LmjF24.0320 and LmjF29.1960 encoding the putative enzymes LmFH-1 and LmFH-2, respectively. In the present work, the FH activity of both L. major enzymes has been confirmed. Circular dichroism studies suggest important differences in terms of secondary structure content when comparing LmFH isoforms and even larger differences when comparing them to the homologous human enzyme. CD melting experiments revealed that both LmFH isoforms are thermolabile enzymes. The catalytic efficiency under aerobic and anaerobic environments suggests that they are both highly sensitive to oxidation and damaged by oxygen. Intracellular localization studies located LmFH-1 in the mitochondrion, whereas LmFH-2 was found predominantly in the cytosol with possibly also some in glycosomes. The high degree of sequence conservation in different Leishmania species, together with the relevance of FH activity for the energy metabolism in these parasites suggest that FHs might be exploited as targets for broad-spectrum antileishmanial drugs. (c) 2012 Elsevier B.V. All rights reserved.

Effect of heat and moisture exchangers on the prevention of ventilator-associated pneumonia in critically ill patients

Ventilator-associated pneumonia (VAP) remains one of the major causes of infection in the intensive care unit (ICU) and is associated with the length of hospital stay, duration of mechanical ventilation, and use of broad-spectrum antibiotics. We compared the frequency of VAP 10 months prior to (pre-intervention group) and 13 months after (post-intervention group) initiation of the use of a heat and moisture exchanger (HME) filter. This is a study with prospective before-and-after design performed in the ICU in a tertiary university hospital. Three hundred and fourteen patients were admitted to the ICU under mechanical ventilation, 168 of whom were included in group HH (heated humidifier) and 146 in group HME. The frequency of VAP per 1000 ventilator-days was similar for both the HH and HME groups (18.7 vs 17.4, respectively; P = 0.97). Duration of mechanical ventilation (11 vs 12 days, respectively; P = 0.48) and length of ICU stay (11 vs 12 days, respectively; P = 0.39) did not differ between the HH and HME groups. The chance of developing VAP was higher in patients with a longer ICU stay and longer duration of mechanical ventilation. This finding was similar when adjusted for the use of HME. The use of HME in intensive care did not reduce the incidence of VAP, the duration of mechanical ventilation, or the length of stay in the ICU in the study population.

Biological and physicochemical stability of ceftazidime and aminophylline on glucose parenteral solution

Ceftazidime is a broad spectrum antibiotic administered mainly by the parenteral route, and it is especially effective against Pseudomonas aeruginosa. The period of time in which serum levels exceed the Minimum Inhibitory Concentration (MIC) is an important pharmacodynamic parameter for its efficacy. One of the forms to extend this period is to administer the antibiotic by continuous infusion, after prior dilution in a Parenteral Solution (PS). The present work assessed the stability of ceftazidime in 5% glucose PS for 24 hours, combined or not with aminophylline, through High Performance Liquid Chromatography (HPLC). The physicochemical evaluation was accompanied by in vitro antimicrobial activity compared MIC test in the 24-hour period. Escherichia coli and Pseudomonas aeruginosa were the microorganisms chosen for the MIC comparison. The HPLC analysis confirmed ceftazidime and aminophylline individual stability on PS, while the MIC values were slightly higher than the mean described in the literature. When both drugs were associated in the same PS, the ceftazidime concentration by HPLC decreased 25% after 24 hours. Not only did the MIC values show high loss of antibiotic activity within the same period, but also altered MIC values immediately after the preparation, which was not detected by HPLC. Our results indicate that this drug combination is not compatible, even if used right away, and that PS might not be the best vehicle for ceftazidime, emphasizing the importance of the MIC evaluation for drug interactions.

Biological and physicochemical stability of ceftazidime and aminophylline on glucose parenteral solution

Ceftazidime is a broad spectrum antibiotic administered mainly by the parenteral route, and it is especially effective against Pseudomonas aeruginosa. The period of time in which serum levels exceed the Minimum Inhibitory Concentration (MIC) is an important pharmacodynamic parameter for its efficacy. One of the forms to extend this period is to administer the antibiotic by continuous infusion, after prior dilution in a Parenteral Solution (PS). The present work assessed the stability of ceftazidime in 5% glucose PS for 24 hours, combined or not with aminophylline, through High Performance Liquid Chromatography (HPLC). The physicochemical evaluation was accompanied by in vitro antimicrobial activity compared MIC test in the 24-hour period. Escherichia coli and Pseudomonas aeruginosa were the microorganisms chosen for the MIC comparison. The HPLC analysis confirmed ceftazidime and aminophylline individual stability on PS, while the MIC values were slightly higher than the mean described in the literature. When both drugs were associated in the same PS, the ceftazidime concentration by HPLC decreased 25% after 24 hours. Not only did the MIC values show high loss of antibiotic activity within the same period, but also altered MIC values immediately after the preparation, which was not detected by HPLC. Our results indicate that this drug combination is not compatible, even if used right away, and that PS might not be the best vehicle for ceftazidime, emphasizing the importance of the MIC evaluation for drug interactions.

Complete Sequence of Broad-Host-Range Plasmid pRIO-5 Harboring the Extended-Spectrum-beta-Lactamase Gene bla(BES-1)

Broad-host-range plasmid pRIO-5, harboring the extended-spectrum beta-lactamase bla(BES-1) gene in Serratia marcescens, was fully sequenced. Analysis of the 12,957-bp sequence of this IncP6-type plasmid revealed that the bla(BES-1) gene was associated with two copies of the insertion sequence IS26. The promoter responsible for the bla(BES-1) expression was hybrid, made of a - 35 box located inside the inverted repeat of IS26 and a - 10 box inside a remnant of an insertion sequence.

Broad combined orange-red emissions from Eu2+- and Eu3+-doped low-silica calcium aluminosilicate glass

In this paper, a broad combined orange-red emission from Eu2+- and Eu3+-doped low-silica calcium aluminosilicate (LSCAS) glass is reported. Spectroscopic results demonstrate that it is possible to tune the emission wavelength by changing the excitation wavelength in the UV-Vis region. The color coordinates for the emission spectra were calculated, and using the Commission Internationale de l'Eclairage 1931 and 1976 chromatic diagrams, it is possible to note that they are dependent on the excitation wavelength. In addition, the (u', v') color coordinates for the investigated LSCAS samples are close to the Planckian spectrum in the cold region between 2000 and 2600K. Our results show that the Eu:LSCAS system can be used in a white light phosphor when mixed in aggregate with phosphors using green-yellow luminescent ions. (c) 2012 Optical Society of America

Mutation Spectrum in the Large GTPase Dynamin 2, and Genotype-Phenotype Correlation in Autosomal Dominant Centronuclear Myopathy

Centronuclear myopathy (CNM) is a genetically heterogeneous disorder associated with general skeletal muscle weakness, type I fiber predominance and atrophy, and abnormally centralized nuclei. Autosomal dominant CNM is due to mutations in the large GTPase dynamin 2 (DNM2), a mechanochemical enzyme regulating cytoskeleton and membrane trafficking in cells. To date, 40 families with CNM-related DNM2 mutations have been described, and here we report 60 additional families encompassing a broad genotypic and phenotypic spectrum. In total, 18 different mutations are reported in 100 families and our cohort harbors nine known and four new mutations, including the first splice-site mutation. Genotype-phenotype correlation hypotheses are drawn from the published and new data, and allow an efficient screening strategy for molecular diagnosis. In addition to CNM, dissimilar DNM2 mutations are associated with Charcot-Marie-Tooth (CMT) peripheral neuropathy (CMTD1B and CMT2M), suggesting a tissue-specific impact of the mutations. In this study, we discuss the possible clinical overlap of CNM and CMT, and the biological significance of the respective mutations based on the known functions of dynamin 2 and its protein structure. Defects in membrane trafficking due to DNM2 mutations potentially represent a common pathological mechanism in CNM and CMT. Hum Mutat 33: 949-959, 2012. (C) 2012 Wiley Periodicals, Inc.