A technique to produce thin cucurbit[6]uril films

We report a methodology to obtain thin films of cucurbit[6]uril, starting from ammoniacal solutions. This technique is very useful for the obtention of modified electrodes or other substrates for sensor purposes. Cucurbit[6]uril is insoluble in most media, and film formation was impossible until now.

Reverse Microemulsion Synthesis, Structure, and Luminescence of Nanosized REPO(4):Ln(3+) (RE = La, Y, Gd, or Yb, and Ln = Eu, Tm, or Er)

A surfactant-mediated solution route for the obtainment of nanosized rare-earth orthophosphates of different compositions (LaPO(4):Eu(3+), (Y,Gd)PO(4):Eu(3+),LaPO(4):Tm(3+), YPO(4):Tm(3+), and YbPO(4):Er(3+)) is presented, and the implications of the morphology control on the solids properties are discussed. The solids are prepared in water-in-heptane microemulsions, using cetyltrimethylammonium bromide and 1-butanol as the surfactant and cosurfactant; the alteration of the starting microemulsion composition allows the obtainment of similar to 30 nm thick nanorods with variable length. The morphology and the structure of the solids were evaluated through scanning electron microscopy and through powder X-ray diffractometry; dynamic light scattering and thermal analyses were also performed. The obtained materials were also characterized through vibrational (FTIR) and luminescence spectroscopy (emission/excitation, luminescence lifetimes, chromaticity, and quantum efficiency), where the red, blue, and upconversion emissions of the prepared phosphors were evaluated.

Voltammetric determination of cocaine in confiscated samples using a cobalt hexacyanoferrate film-modified electrode

In this work, a fast, non destructive voltammetric method for cocaine detection in acetonitrile medium using a platinum disk electrode chemically modified with cobalt-hexacyanoferrate (CoHCFe) film is described. The deposition of CoHCFe film at platinum disk (working electrode) was carried out in aqueous solution containing NaClO(4) at 0.1 mol L(-1) as supporting electrolite. Stability studies of the film and subsequent voltammetric analysis of cocaine were made in acetonitrile medium with NaClO4 at 0.1 mol L(-1) as supporting electrolite. A reversible interaction between cocaine and CoHCFe at the film produces a proportional decrease of original peak current, due to the formation of a complex between cocaine and cobalt ions, with subsequent partial passivation of the film surface, being the intensity of current decrease used as analytical signal for cocaine. A linear dependence of cocaine detection was carried out in the range from 2.4 x 10 x 4 to 1.5 x 10(-3) mol L(-1), with a linear correlation coefficient of 0.994 and a detection limit of 1.4 x 10 x 4 mol L(-1). The analysis of confiscated samples by the proposed method indicated cocaine levels from 37% to 95% (m/m) and these results were validated by comparison to HPLC technique, being obtained good correlation between both methods. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

Hemolymph ionic regulation and adjustments in gill (Na(+), K(+))-ATPase activity during salinity acclimation in the swimming crab Callinectes ornatus (Decapoda, Brachyura)

We evaluate hemolymph osmotic and ionic regulatory abilities and characterize a posterior gill microsomal (Na(+), K(+))-ATPase from the marine swimming crab, Callinectes ornatus, acclimated to 21 parts per thousand or 33 parts per thousand salinity. C ornatus is isosmotic after acclimation to 21 parts per thousand but is hyposmotic at 33 parts per thousand salinity; hemolymph ions do not recover initial levels on acclimation to 21 parts per thousand salinity but are anisoionic compared to ambient concentrations, revealing modest regulatory ability. NH(4)(+) modulates enzyme affinity for K(+), which increases 187-fold in crabs acclimated to 33%. salinity. The (Na(+), K(+))-ATPase redistributes into membrane fractions of different densities, suggesting that altered membrane composition results from salinity acclimation. ATP was hydrolyzed at maximum rates of 182.6 +/- 7.1 nmol Pi min(-1) mg(-1) (21 parts per thousand) and 76.2 +/- 3.5 nmol Pi min(-1) mg(-1) (33 parts per thousand), with little change in K(M) values (approximate to 50 mu mol L(-1)). K(+) together with NH(4)(+) synergistically stimulated activity to maximum rates of approximate to 240 nmol Pi min(-1) mg(-1). K, values for ouabain inhibition (approximate to 110 mu mol L(-1)) decreased to 44.9 +/- 1.0 mu mol L(-1) (21 parts per thousand) and 28.8 +/- 1.3 mu mol L(-1) (33 parts per thousand) in the presence of both K(+) and NH(4)(+). Assays employing various inhibitors suggest the presence of mitochondrial F(0)F(1)- and K(+)- and V-ATPase activities in the gill microsomes. (C) 2009 Elsevier Inc. All rights reserved.

Solvent Effects in Optical Spectra of ortho-Aminobenzoic Acid Derivatives

We investigated three amino derivatives of ortho-aminobenzoic or anthranilic acid (o-Abz): a) 2-Amino-benzamide (AbzNH(2)); b) 2-Amino-N-methyl-benzamide (AbzNHCH(3)) and c) 2-Amino-N-N`-dimethyl-bezamide (AbzNH(CH(3))(2)), see Scheme 1. We describe the results of ab-initio calculations on the structural characteristics of the compounds and experimental studies about solvent effects in their absorption and steady-state and time-resolved emission properties. Ab-initio calculations showed higher stability for the rotameric conformation in which the oxygen of carbonyl is near to the nitrogen of ortho-amino group. The derivatives present decrease in the delocalization of pi electron, and absorption bands are blue shifted compared to the parent compound absorption, the extent of the effect increasing from to Abz-NH(2) to Abz-NHCH(3) Abz-NH(CH(3))(2). Measurements performed in several solvents have shown that the the dependence of Stokes shift of the derivatives with the orientational polarizability follows the Onsager-Lippert model for general effects of solvent. However deviation occurred in solvents with properties of Bronsted acids, or electron acceptor characteristics, so that hydrogen bonds formed with protic solvents predominates over intramolecular hydrogen bond. In most solvents the fluorescence decay of AbzNH(2) and AbzNHCH(3) was fitted to a single exponential with lifetimes around 7.0 ns and no correlation with polarity of the solvent was observed. The fluorescence decay of AbzN(CH(3))(2) showed lifetimes around 2.0 ns, consistent with low quantum yield of the compound. The spectroscopic properties of the monoamino derivative AbzNHCH(3) are representative of the properties presented by Abz labelled peptides and fatty acids previously studied.

Impact of photodynamic therapy on inflammatory cells during human chronic periodontitis

The aim of this study was to evaluate the effects of the photodynamic therapy (PDT) on the inflammatory infiltrate and on the collagen network organization in human advanced chronic periodontitis Two different drug delivery systems (DDS) were tested (liposomes and nanoemulsions) to determine if the effects of PDT could differ according to the DDS used Sixteen patients presenting two teeth with chronic advanced periodontitis and Important tooth mobility with clinical indication of extraction were included in the group liposomes (group L n = 8) or in the group nanoemulsions (group N n = 8) in order to compare the effects of each DDS Seven days before extractions one tooth of each patient was treated with PDT using phthalocyanine derivatives as photosensitizers and the contralateral tooth was taken as control In group L the density of gingival collagen fibers (66 +/- 19%) was significantly Increased (p < 0 02) when compared to controls (35 +/- 21%) Concerning the antigen-presenting cells PDT had differential effects depending on the drug delivery system the number of macrophages was significantly decreased (p < 0 05) in group L while the number of Langerhans cells was significantly decreased in group N (p < 0 02) These findings demonstrate that PDT presents an impact on gingival Inflammatory phenomenon during chronic periodontitis and leads to a specific decrease of antigen-presenting cells populations according to the drug delivery system used (C) 2010 Elsevier B V All rights reserved

Structural and Biochemical Correlates of Na(+), K(+)-ATPase Driven Ion Uptake Across the Posterior Gill Epithelium of the True Freshwater Crab, Dilocarcinus pagei (Brachyura, Trichodactylidae)

To better comprehend the structural and biochemical underpinnings of ion uptake across the gills of true freshwater crabs, we performed an ultrastructural, ultracytochemical and morphometric investigation, and kinetically characterized the Na(+), K(+)-ATPase, in posterior gill lamellae of Dilocarcinus pagei. Ultrastructurally, the lamellar epithelia are markedly asymmetrical: the thick, mushroom-shaped, proximal ionocytes contain elongate mitochondria (41% cell volume) associated with numerous (approximate to 14 mu m(2) membrane per mu m(3) cytoplasm), deep invaginations that house the Na(+), K(+)-ATPase, revealed ultracytochemically. Their apical surface is amplified (7.5 mu m(2) mu m(-2)) by stubby evaginations whose bases adjoin mitochondria below the subcuticular space. The apical membrane of the thin, distal ionocytes shows few evaginations (1.6 mu m(2) mu m(-2)), each surrounding a mitochondrion, abundant in the cytoplasm below the subcuticular space; basolateral invaginations and mitochondria are few. Fine basal cytoplasmic bridges project across the hemolymph space, penetrating into the thick ionocytes, suggesting ion movement between the epithelia. Microsomal Na(+), K(+)-ATPase specific activity resembles marine crabs but is approximate to 5-fold less than in species from fluctuating salinities, and freshwater shrimps, suggesting ion loss compensation by strategies other than Na(+) uptake. Enzyme apparent K(+) affinity attains 14-fold that of marine crabs, emphasizing the relevance of elevated K(+) affinity to the conquest of fresh water. Western blotting and biphasic ouabain inhibition disclose two alpha-subunit isoforms comprising distinct functional isoenzymes. While enzyme activity is not synergistically stimulated by NH(4)(+) and K(+), each increases affinity for the other, possibly assuring appropriate intracellular K(+) concentrations. These findings reveal specific structural and biochemical adaptations that may have allowed the establishment of the Brachyura in fresh water. J. Exp. Zool. 313A:508-523, 2010. (C) 2010 Wiley-Liss, Inc.

The 2.0 angstrom crystal structure of a pocilloporin at pH 3.5: The structural basis for the linkage between color transition and halide binding

The pocilloporin Rtms5 and an engineered variant Rtms5(H146S) undergo distinct color transitions (from blue to red to yellow to colorless) in a pH-dependent manner. pK(a) values of 4.1 and 3.2 were determined for the blue (absorption lambda(max), 590 nm) to yellow (absorption lambda(max), similar to 453 nm) transitions of Rtms5 and Rtms5H(146). The pK(a) for the blue-yellow transition of Rtms5H(146S) increased by 1.4 U in the presence of 0.1 M KI, whereas the pK(a) for the same transition of Rtms5 was relatively insensitive to added halides. To understand the structural basis for these observations, we have determined to 2.0 A resolution the crystal structure of a yellow form of Rtms5(H146S) at pH 3.5 in the presence of iodide. Iodide was found occupying a pocket in the structure with a pH of 3.5, forming van der Waals contacts with the tyrosyl moiety of the chromophore. Elsewhere, it was determined that this pocket is occupied by a water molecule in the Rtms5(H141S) structure (pH 8.0) and by the side chain of histidine 146 in the wild-type Rtms5 structure. Collectively, our data provide an explanation for the observed linkage between color transitions for Rtms5(H146S) and binding to halides.

Ultraviolet signals ultra-aggression in a lizard

Understanding the role of multiple colour signals during sexual signalling is a central theme in animal communication. We quantified the role of multiple colour signals (including ultraviolet, UV), measures of body size and testosterone levels in settling disputes between male rivals in an elaborately ornamented, African lizard, played out in a large 'tournament' in the wild. The hue and brightness (total reflectance) of the UV throat in Augrabies flat lizards, Platysaurus broadleyi, as well as body size, were consistent and strong predictors of 'fighting ability'. Males with high fighting ability were larger and displayed a UV throat with low total reflectance. In contrast, males with low fighting ability were smaller and had violet throats with broader spectral reflectance curves (higher total reflectance). As fighting ability is associated with alternative reproductive tactics in this system (territorial versus floater), we also examined the role of colour signals in predicting male reproductive tactic. Territorial males had UV throats with higher chroma but had poorer body condition than floater males, probably because of the energetic costs of maintaining a territory. Although testosterone was not a significant predictor of fighting ability or reproductive tactic, it was correlated with the hue of the UV throat, suggesting that testosterone may impose some constraint on signal expression. Lastly, we show that within the context of the natural signalling environment, UV-reflective throats constitute a conspicuous, effective signal that male Augrabies flat lizards use to advertise their status honestly to rivals. (c) 2006 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Gut ischemia/reperfusion induced acute lung injury is an alveolar macrophage dependent event

Background:. Although the role of the lung alveolar macrophage (AM) as a mediator of acute lung injury (ALI) after lung ischemia/reperfusion (I/R) has been suggested by animal experiments, it has not been determined whether AMs mediate ALI after intestinal I/R. The objective of this study was to determine the effect of AM elimination on ALI after intestinal I/R in rats. Mwthods: Male Wistar rats (n = 90) were randomly divided into three groups: the clodronate-liposomes (CLOD-LIP) group received intratracheal treatment with CLOD-LIP; the liposomes (LIP) group received intratracheal treatment with LIP; and the nontreated (UNTREAT) group received no treatment. Twenty-four hours later each group was randomly divided into three subgroups: the intestinal I/R subgroup was subjected to 45-minute intestinal ischemia and 2-hour reperfusion; the laparotomy (LAP) subgroup was subjected to LAP and sham procedures; the control (CTR) subgroup received no treatment. At the end of reperfusion, ALI was quantitated in all the animals by the Evans blue dye (EBD) method. Results: ALI values are expressed as EBD lung leakage (mu g EBD/g dry lung weight). EBD lung leakage values in the CLOD-LIP group were 32.59 +/- 12.74 for I/R, 27.74 +/- 7.99 for LAP, and 33.52 +/- 10.17 for CTR. In the LIP group, lung leakage values were 58.02 +/- 18.04 for I/R, 31.90 +/- 8.72 for LAP, and 27.17 +/- 11.48 for CTR. In the UNTREAT group, lung leakage values were 55.60 +/- 10.96 for I/R, 35.99 +/- 6.89 for LAP, and 30.83 +/- 8.41 for CTR. Within each group, LAP values did not differ from CTR values. However, in the LIP and UNTREAT groups, values for both the LAP and CTR subgroups were lower than values for the I/R subgroup (p < 0.001). The CLOD-LIP I/R subgroup value was less (p < 0.001) than the I/R subgroup values in the LIP and UNTREAT groups. These results indicated that I/R provokes ALI that can be prevented by CLOD-LIP treatment, and further suggested that AMs are essential for ALI occurrence induced by intestinal I/R in rats.

A quantitative chemiluminescent method for studying replicative and stress-induced premature senescence in cell cultures

beta-Galactosidase (beta-Gal) activity is a widely accepted biomarker to detect senescence both in situ and in vitro. A cytochemical assay based on production of a blue-dyed precipitate that results from the cleavage of the chromogenic substrate X-Gal is commonly used. Blue and nonblue cells are counted under the microscope and a semiquantitative percentage of senescent cells can be obtained. Here, we present a quantitative, fast, and easy to use chemiluminescent assay to detect senescence. The Galacton chemiluminescent method used to detect the prokaryotic beta-Gal reporter enzyme in transfection studies was adapted to assay mammalian beta-Gal. The assay showed linear production of luminescence in a time- and cell-number-dependent manner. The chemiluminescent assay showed significant correlation with the cytochemical assay in detecting replicative senescence (Pearson r = 0.8486, p < 0.005). Moreover, the chemiluminescent method (Galacton) also detected stress-induced senescence in cells treated with H2O2 similar to the cytochemical assay (X-Gal) (Galacton: control 25.207.3 +/- 6548.6. H2O, 52,487.4 +/- 16,284.9, p < 0.05; X-Gal: control 41.31 +/- 7.0%, H2O2 92.97 +/- 2.8%, p < 0.01). Thus, our method is well suited to the detection of replicative and stress-induced senescence in cell culture. (C) 2007 Elsevier Inc. All rights reserved.

Role of nitric oxide in hyperpnea-induced bronchoconstriction and airway microvascular permeability in guinea pigs

The present study aimed to evaluate the role of nitric oxide (NO) on hyperpnea-induced bronchoconstriction (HIB) and airway microvascular hyperpermeability (AMP). Sixty-four guinea pigs were anesthetized, tracheotonnized, cannulated, and connected to animal ventilator to obtain pulmonary baseline respiratory system resistance (Rrs). Animals were then submitted to 5 minutes hyperpnea and Rrs was evaluated during 15 minutes after hyperpnea. AMP was evaluated by Evans blue dye (25 mg/kg) extravasation in airway tissues. Constitutive and inductible NO was evaluated by pretreating animals with N(G)-nitro-1-arginine methyl ester (I-NAME) (50 mg/kg), aminoguadinine (AG) (50 mg/kg), and I-arginine (100 mg/kg) and exhaled NO (NOex) was evaluated before and after drug administration and hyperpnea. The results show that I-NAME potentiated (57%) HIB and this effect was totally reversed by I-arginine pretreatment, whereas AG did not have effect on HIB. I-NAME decreased basal AMP (48%), but neither I-NAME nor AG had any effect on hyperpnea-induced AMP. NOex levels were decreased by 50% with I-NAME, effect that was reversed by I-arginine treatment. These results suggest that constitutive but not inducible NO could have a bronchoprotective effect on HIB in guinea pigs. The authors also observed that neither constitutive nor inducible NO seems to have any effect on hyperpnea-induced AMP.

The structure of versutoxin (delta-atracotoxin-Hv1) provides insights into the binding of site 3 neurotoxins to the voltage-gated sodium channel

Background: Versutoxin (delta-ACTX-Hv1) is the major component of the venom of the Australian Blue Mountains funnel web spider, Hadronyche versuta. delta-ACTX-Hv1 produces potentially fatal neurotoxic symptoms in primates by slowing the inactivation of voltage-gated sodium channels; delta-ACTX-Hv1 is therefore a useful tool for studying sodium channel function. We have determined the three-dimensional structure of delta ACTX-Hv1 as the first step towards understanding the molecular basis of its interaction with these channels. Results: The solution structure of delta-ACTX-Hv1, determined using NMR spectroscopy, comprises a core beta region containing a triple-stranded antiparallel beta sheet, a thumb-like extension protruding from the beta region and a C-terminal 3(10) helix that is appended to the beta domain by virtue of a disulphide bond. The beta region contains a cystine knot motif similar to that seen in other neurotoxic polypeptides. The structure shows homology with mu-agatoxin-l, a spider toxin that also modifies the inactivation kinetics of vertebrate voltage-gated sodium channels. More surprisingly, delta-ACTX-Hv1 shows both sequence and structural homology with gurmarin, a plant polypeptide. This similarity leads us to suggest that the sweet-taste suppression elicited by gurmarin may result from an interaction with one of the downstream ion channels involved in sweet-taste transduction. Conclusions: delta-ACTX-Hv1 shows no structural homology with either sea anemone or alpha-scorpion toxins, both of which also modify the inactivation kinetics of voltage-gated sodium channels by interacting with channel recognition site 3. However, we have shown that delta-ACTX-Hv1 contains charged residues that are topologically related to those implicated in the binding of sea anemone and alpha-scorpion toxins to mammalian voltage-gated sodium channels, suggesting similarities in their mode of interaction with these channels.

Ultrastructural evaluation of gingival glycosaminoglycans in ovariectomized rats: Effects of steroid hormone therapy

Background/Aims: To evaluate the behavior of glycosaminoglycans (GAGs) in rat gingiva and the effects of lack of sexual steroids and the hormonal therapy with estrogen and dexamethasone (DEX). Methods: 40 female rats were divided into four groups: GI: animals in permanent estrus; GII: ovariectomized (OVX) animals + vehicle; GIII: OVX animals treated with 17 beta-estradiol benzoate (10 mu g/kg), and GIV: OVX animals treated with 17 beta-estradiol benzoate (10 mu g/kg) + DEX (3 mg/kg). After treatment, the gingiva was removed and its GAGs content was evaluated by electronic microscopy after stained by cuprolinic blue technique. Results: The electron-microscopic data showed that low values of chondroitin sulfate were found in castrated animals (35.05 +/- 3.58%) compared to other groups (GI: 41.17 +/- 1.13; GIII: 48.04 +/- 2.60; GIV: 49.09 +/- 2.68%). In contrast, the amount of dermatan sulfate in GII (57.70 +/- 2.50%) was higher than in the other groups (GI: 46.12 +/- 1.30; GIII: 42.65 +/- 2.98; GIV: 42.68 +/- 5.43%). Conclusions: GAGs may be influenced by estradiol, and DEX did not seem to antagonize the role of estradiol in the GAGs of gingiva. The histotypical structure of gingiva is related to the amount of chondroitin sulfate. Consequently, the estrogen therapy may be important for gingival health. Copyright (C) 2007 S. Karger AG, Basel.

Monoclonal anti-vascular endothelial growth factor antibody reduces fluid volume in an experimental model of inflammatory pleural effusion

Background and objective: Vascular endothelial growth factor (VEGF) is known to increase vascular permeability and promote angiogenesis. It is expressed in most types of pleural effusions. However, the exact role of VEGF in the development of pleural effusions has yet to be determined. The anti-VEGF mAb, bevacizumab, has been used in the treatment of cancer to reduce local angiogenesis and tumour progression. This study describes the acute effects of VEGF blockade on the expression of inflammatory cytokines and pleural fluid accumulation. Methods: One hundred and twelve New Zealand rabbits received intrapleural injections of either talc or silver nitrate. In each group, half the animals received an intravenous injection of bevacizumab, 30 min before the intrapleural agent was administered. Five animals from each subgroup were sacrificed 1, 2, 3, 4 or 7 days after the procedure. Twelve rabbits were used to evaluate vascular permeability using Evans`s blue dye. Pleural fluid volume and cytokines were quantified. Results: Animals pretreated with anti-VEGF antibody showed significant reductions in pleural fluid volumes after talc or silver nitrate injection. IL-8 levels, vascular permeability and macroscopic pleural adhesion scores were also reduced in the groups that received bevacizumab. Conclusions: This study showed that bevacizumab interferes in the acute phase of pleural inflammation induced by silver nitrate or talc, reinforcing the role of VEGF as a key mediator in the production of pleural effusions. The results also suggest that bevacizumab should probably be avoided in patients requiring pleurodesis.