Advances in sickle cell disease treatment: From drug discovery until the patient monitoring

Sickle Cell Disease (SCD) is one of the most prevalent hematological diseases in the world. Despite the immense progress in molecular knowledge about SCD in last years few therapeutical sources are currently available. Nowadays the treatment is performed mainly with drugs such as hydroxyurea or other fetal hemoglobin inducers and chelating agents. This review summarizes current knowledge about the treatment and the advancements in drug design in order to discover more effective and safe drugs. Patient monitoring methods in SCD are also discussed. © 2011 Bentham Science Publishers Ltd.

Influence of concentration, time and method of application of citric acid and sodium citrate in root conditioning.

The aim of this study was to establish the parameters of concentration, time and mode of application of citric acid and sodium citrate in relation to root conditioning. A total of 495 samples were obtained and equally distributed among 11 groups (5 for testing different concentrations of citric acid, 5 for testing different concentrations of sodium citrate and 1 control group). After laboratorial processing, the samples were analyzed under scanning electron microscopy. A previously calibrated and blind examiner evaluated micrographs of the samples. Non-parametric statistical analysis was performed to analyze the data obtained. Brushing 25% citric acid for 3 min, promoted greater exposure of collagen fibers in comparison with the brushing of 1% citric acid for 1 minute and its topical application at 1% for 3 min. Sodium citrate exposed collagen fibers in a few number of samples. Despite the lack of statistical significance, better results for collagen exposure were obtained with brushing application of 25% citric acid for 3 min than with other application parameter. Sodium citrate produced a few number of samples with collagen exposure, so it is not indicated for root conditioning.

Blood cells attachment after root conditioning and PRP application: An in vitro study

Aim: Root conditioning is aimed at smear layer removal and at dental matrix collagen exposure, which may promote periodontal regeneration. This in vitro study assessed smear layer removal, collagen fiber exposure and the influence of PRP (platelet-rich plasma) application on adhesion of blood cells to the root surface using scanning electron microscopy (SEM). Materials and methods: Scaled root samples (n = 160) were set in five groups and conditioned with: group I - control group (saline solution); group II (EDTA 24%); group III (citric acid 25%); group IV (tetracycline hydrochloride 50 mg/ml); group V (sodium citrate 30%). Eighty samples were assessed using the root surface modification index (RSMI). The other eighty samples were set in two groups. The first group (n = 40) received PRP gel application with a soft brush and the second group (n = 40) received PRP application and then a blood drop. The fibrin clot formation was assessed in the first group and the blood cells adhesion was assessed in the second group using the BEAI (blood elements adhesion index). A previously trained, calibrated, and blind examiner evaluated photomicrographs. Statistical analysis was performed using the Kruskal-Wallis's and Dunn's tests. Results: Group III attained the best results for RSMI and BEAI. Moreover, it was the only group showing fibrin clot formation. Conclusion: Citric acid was the most efficient conditioner for smear layer removal, collagen fiber exposure and blood cell adhesion. Moreover, it was the only group showing fibrin clot formation after PRP application. Clinical significance: This study demonstrated that root conditioning followed by PRP application may favor blood cell adhesion on root surface which may optimize periodontal healing.

Isolamento, purificação e caracterização da peroxidase de yacon (Smallanthus sonchifolius)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Desenvolvimento de técnicas e avaliações de antimicrobianos visando a produção de etanol carburante

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The antimicrobial effect of new and conventional endodontic irrigants on intra-orally infected dentin

Objectives. To evaluate if the incorporation of antimicrobial compounds to chelating agents or the use of chelating agents with antimicrobial activity as 7% maleic acid and peracetic acid show similar disinfection ability in comparison to conventional irrigants as sodium hypochlorite or iodine potassium iodide against biofilms developed on dentin. Materials and methods. The total bio-volume of live cells, the ratio of live cells and the substratum coverage of dentin infected intra-orally and treated with the irrigant solutions: MTAD, Qmix, Smear Clear, 7% maleic acid, 2% iodine potassium iodide, 4% peracetic acid, 2.5% and 5.25% sodium hypochlorite was measured by using confocal microscopy and the live/dead technique. Five samples were used for each irrigant solution. Results. Several endodontic irrigants containing antimicrobials as clorhexidine (Qmix), cetrimide (Smear Clear), maleic acid, iodine compounds or antibiotics (MTAD) lacked an effective antibiofilm activity when the dentin was infected intra-orally. The irrigant solutions 4% peracetic acid and 2.5–5.25% sodium hypochlorite decrease significantly the number of live bacteria in biofilms, providing also cleaner dentin surfaces (p < 0.05). Conclusions. Several chelating agents containing antimicrobials could not remove nor kill significantly biofilms developed on intra-orally infected dentin, with the exception of sodium hypochlorite and 4% peracetic acid. Dissolution ability is mandatory for an appropriate eradication of biofilms attached to dentin.

Metallkomplexe mit sterisch anspruchsvollen mono- und bifunktionellen Triazenidoliganden

Monoanionische, stickstoffhaltige Chelatliganden sind sehr populär und werden oft als Baueinheiten zur Synthese von Metallkomplexen eingesetzt. Im Gegensatz zu den bekannten Amidinat- und β-Diketiminatliganden wurde den Triazeniden bisher weniger Aufmerksamkeit geschenkt. Dies liegt hauptsächlich daran, dass wenige, sterisch anspruchsvolle Vertreter dieser Gruppe bekannt waren. Mit der Synthese neuer biphenyl- und terphenylsubstituierter Triazenide sind diese stärker in den Fokus der Forschung gerückt. Durch die Sperrigkeit der Liganden werden unerwünschte Ligandenumverteilungsreaktionen unterdrückt und der Weg zu neuen Metallkomplexen mit bemerkenswerten Eigenschaften geebnet. Diese Arbeit beschäftigt sich mit Triazenidokomplexen der Alkalimetalle, des Magnesiums, des Zinks und des Aluminiums. Zusätzlich zu den monofunktionellen wurden bifunktionelle Triazene, welche aus einer Biphenylgruppe aufgebaut sind und zwei terphenylsubstituierte Triazengruppen tragen, synthetisiert und deren Funktion als Komplexliganden untersucht. Durch das hohe Volumen der Liganden konnten Metallkomplexe hergestellt werden, die bemerkenswerte strukturelle Eigenschaften aufweisen. So bilden beispielsweise alle dargestellten Verbindungen Kristalle, die aus monomeren Baueinheiten aufgebaut sind. Eine homoleptische Magnesiumverbindung mit zwei Triazenidliganden weist eine ungewöhnliche, planare Koordinationssphäre auf, eine Triazenidodiphenylaluminiumverbindung zeigt eine interessante Ausrichtung der Phenylgruppen, die auf π-Stapeleffekte zurückgeführt wird und die Alkalimetalltriazenide weisen sekundäre Metall-π-Aren-Wechselwirkungen auf, womit eine bessere koordinative Absättigung des Koordinationszentrums erreicht wird. Zusätzlich zur strukturellen Charakterisierung mittels Röntgendiffraktometrie wurden, wo es möglich war 1H und 13C NMR-Messungen durchgeführt, Schmelzpunkte bestimmt sowie IR- und UV-VIS-Spektren aufgenommen. Durch die hohe Dichte an aromatischen Systemen innerhalb der Verbindungen, ist es bei einer dreikernigen Zinktriazenidverbindung gelungen mittels 1H NMR-Messungen die starken Einflüsse des Ringstroms nachzuweisen. Außerdem wurden DFT-Berechnungen durchgeführt, um herauszufinden, wie sehr die räumliche Ausrichtung der Bi- bzw. Terphenylsubstituenten gegenüber der N3-Baugruppe der Triazenide die Verteilung der negativen Ladung innerhalb eines monoanionischen Triazenids und somit dessen Koordinationseigenschaften beeinflusst. Diese Effekte konnten durch experimentelle Ergebnisse unterstützt werden.

Nanopartikel und Nanokapseln als potentielle Wirkstofftransportsysteme : zelluläre Aufnahme in Leukozyten in peripherem Vollblut und in Zellkultur

Nanopartikuläre Wirkstofftransportsysteme besitzen ein großes Potential für therapeutische Anwendungen. In der vorliegenden Arbeit wurden verschiedene grundlegende Aspekte, die für das erweiterte biologische Verständnis und die Entwicklung weiterer zielgerichteter Strategien zur Pharmakotherapie mit Nanopartikeln und –kapseln notwendig sind, näher untersucht. Experimente zur zellulären Aufnahmefähigkeit (in vitro und ex vivo) wurden mit verschiedenen Nanopartikeln und –kapseln aus diversen Monomeren und biokompatiblen Makromolekülen in immortalisierten Zellkulturlinien, humanen mesenchymalen Stammzellen und Leukozyten durchgeführt und durchflusszytometrisch sowie mittels konfokaler Laser-Raster-Mikroskopie analysiert. Die Einflüsse der Oberflächenfunktionalisierungen der nanopartikulären Systeme, deren toxikologische Effekte sowie der Einfluss von adsorbiertem bovinem Serumalbumin auf funktionalisierten Polystyrol-Nanopartikeln wurden in Bezug auf die zelluläre Aufnahme untersucht.Um die multiplen Wechselwirkungen der Nanopartikel mit Bestandteilen des humanen peripheren Vollblutes zu untersuchen, wurde erfolgreich ein durchflusszytometrisches Analyseverfahren in antikoaguliertem peripherem Vollblut (ex vivo) entwickelt. Es konnte nachgewiesen werden, dass der Einfluss von Calcium-komplexierenden Antikoagulanzien zu einer Verringerung und nicht Li-Heparin zu einer Verstärkung der zellulären Aufnahme von funktionalisierten Polystyrol-Nanopartikeln in diversen Leukozyten führt.Für Folsäure-gekoppelte Hydroxyethylstärke-Nanokapseln (Synthese Frau Dr. Grit Baier) konnte ein größenabhängiger selektiver, Folatrezeptor α vermittelter, zellulärer Aufnahmeweg in HeLa-Zellen nachgewiesen werden.Hydrolysierbare, nicht zytotoxische Polyester-Nanopartikel aus Poly(5,6-Benzo-2-methylen-1,3-dioxepan) (Synthese Herr Dr. Jörg Max Siebert) mit eingebettetem Paclitaxel zeigten in HeLa-Zellen eine vergleichbare pharmakologische Wirkung wie kommerziell erhältliche Paclitaxel-Formulierungen.Die in dieser Arbeit eingesetzten Nanopartikel und Nanokapseln besitzen ein vielfältiges Potential als Wirkstofftransportsysteme. Es zeigte sich, dass Unterschiede bei der Größe, der Größenverteilung, des Polymers sowie der Oberflächenfunktionalisierung der Nanopartikel bedeutende Unterschiede der Zellaufnahme in diversen Zellkulturlinien (in vitro) und Leukozyten in peripherem Vollblut (ex vivo) zur Folge haben.

Long-lasting synaptic potentiation induced by depolarization under conditions that eliminate detectable Ca2+ signals.

Activity-dependent alterations of synaptic transmission important for learning and memory are often induced by Ca(2+) signals generated by depolarization. While it is widely assumed that Ca(2+) is the essential transducer of depolarization into cellular plasticity, little effort has been made to test whether Ca(2+)-independent responses to depolarization might also induce memory-like alterations. It was recently discovered that peripheral axons of nociceptive sensory neurons in Aplysia display long-lasting hyperexcitability triggered by conditioning depolarization in the absence of Ca(2+) entry (using nominally Ca(2+)-free solutions containing EGTA, "0Ca/EGTA") or the absence of detectable Ca(2+) transients (adding BAPTA-AM, "0Ca/EGTA/BAPTA-AM"). The current study reports that depolarization of central ganglia to approximately 0 mV for 2 min in these same solutions induced hyperexcitability lasting >1 h in sensory neuron processes near their synapses onto motor neurons. Furthermore, conditioning depolarization in these solutions produced a 2.5-fold increase in excitatory postsynaptic potential (EPSP) amplitude 1-3 h afterward despite a drop in motor neuron input resistance. Depolarization in 0 Ca/EGTA produced long-term potentiation (LTP) of the EPSP lasting > or = 1 days without changing postsynaptic input resistance. When re-exposed to extracellular Ca(2+) during synaptic tests, prior exposure to 0Ca/EGTA or to 0Ca/EGTA/BAPTA-AM decreased sensory neuron survival. However, differential effects on neuronal health are unlikely to explain the observed potentiation because conditioning depolarization in these solutions did not alter survival rates. These findings suggest that unrecognized Ca(2+)-independent signals can transduce depolarization into long-lasting synaptic potentiation, perhaps contributing to persistent synaptic alterations following large, sustained depolarizations that occur during learning, neural injury, or seizures.

Long-lasting hyperexcitability induced by depolarization in the absence of detectable Ca2+ signals.

Learning and memory depend on neuronal alterations induced by electrical activity. Most examples of activity-dependent plasticity, as well as adaptive responses to neuronal injury, have been linked explicitly or implicitly to induction by Ca(2+) signals produced by depolarization. Indeed, transient Ca(2+) signals are commonly assumed to be the only effective transducers of depolarization into adaptive neuronal responses. Nevertheless, Ca(2+)-independent depolarization-induced signals might also trigger plastic changes. Establishing the existence of such signals is a challenge because procedures that eliminate Ca(2+) transients also impair neuronal viability and tolerance to cellular stress. We have taken advantage of nociceptive sensory neurons in the marine snail Aplysia, which exhibit unusual tolerance to extreme reduction of extracellular and intracellular free Ca(2+) levels. The axons of these neurons exhibit a depolarization-induced memory-like hyperexcitability that lasts a day or longer and depends on local protein synthesis for induction. Here we show that transient localized depolarization of these axons in an excised nerve-ganglion preparation or in dissociated cell culture can induce short- and intermediate-term axonal hyperexcitability as well as long-term protein synthesis-dependent hyperexcitability under conditions in which Ca(2+) entry is prevented (by bathing in nominally Ca(2+) -free solutions containing EGTA) and detectable Ca(2+) transients are eliminated (by adding BAPTA-AM). Disruption of Ca(2+) release from intracellular stores by pretreatment with thapsigargin also failed to affect induction of axonal hyperexcitability. These findings suggest that unrecognized Ca(2+)-independent signals exist that can transduce intense depolarization into adaptive cellular responses during neuronal injury, prolonged high-frequency activity, or other sustained depolarizing events.

Effects of soluble humic acids on the uptake of heavy metals by Vetiveria zizanioides (L.) Nash in contaminated mining soils

In the past, mining wastes were left wherever they might lie in the surroundings of the mine area. Unfortunately, inactive and abandoned mines continue to pollute our environment, reason why these sites should be restored with minimum impact. Phytoextraction is an environmental-friendly and cost-effective technology less harmful than traditional methods that uses metal hyperaccumulator or at least tolerant plants to extract heavy metals from polluted soils. One disadvantage of hyperaccumulator species is their slow growth rate and low biomass production. Vetiveria zizanioides (L.) Nash, perennial species adapted to Mediterranean climate has a strong root system which can reach up to 3 m deep, is fast growing, and can survive in sites with high metal levels (Chen et al., 2004). Due to the fact that metals in abandoned mine tailings become strongly bonded to soil solids, humic acids used as chelating agents could increase metal bioavailability (Evangelou et al., 2004; Wilde et al., 2005) and thereby promote higher accumulation in the harvestable parts of the plant. The objective of this study was to examine the performance of humic acid assisted phytoextraction using Vetiveria zizanioides (L.) Nash in heavy metals contaminated soils.

Structural studies of copper(II)-amine terminated dendrimer complexes by EXAFS

The three-dimensional branched nature of dendritic macromolecules provides many potential sites per molecule for the complexation of metal ions. Therefore, dendrimers may act as hosts for metals with coordination potentially occurring at the periphery, the interior, or both. To understand further the complexation of dendrimers with metal ions EXAFS experiments were carried out. In this work, the interaction of amine-terminated polyamido(amine), PAMAM, dendrimer with copper(II) ions determined by EXAFS is reported. It was found that a model consisting of the copper(II) ion forming five- and six-membered rings by chelating with the primary amine, amide, and tertiary amine nitrogen donors of the PAMAM dendrimer could describe the experimental EXAFS data well. Corroborative evidence for binding to amide nitrogen donors comes from the broadening of NMR resonances of a copper(Il)-PAMAM mixture revealing the presence of paramagnetic copper(II) ions at these sites. The significance of the results presented in this paper is that copper(II) ions form complexes within the dendrimer structure and not just at the periphery. The current study may have implications for the use of PAMAM dendrimers as effective ligands in sensing systems.

Synthesis, characterization and X-ray crystal structures of dinuclear nickel(II) complexes of a novel potentially hexadentate but functionally tetradentate binucleating ligand

A binucleating potentially hexadentate chelating agent containing oxygen, nitrogen and sulfur as potential donor atoms (H2ONNO) has been synthesized by condensing alpha,alpha-xylenebis(N-methyldithiocarbazate) with 2,4-pentanedione. An X-ray crystallographic structure determination shows that the Schiff base remains in its ketoimine tautomeric form with the protons attached to the imine nitrogen atoms. The reaction of the Schiff base with nickel(II) acetate in a 1:1 stoichiometry leads to the formation of a dinuclear nickel(II) complex [Ni(ONNO)](2) (ONNO2- = dianionic form of the Schiff base) containing N,O-chelated tetradentate ligands, the sulfur donors remaining uncoordinated. A single crystal X-ray structure determination of this dimer reveals that each ligand binds two low spin nickel(II) ions, bridged by a xylyl group. The nickel(II) atoms adopt a distorted square-planar geometry in a trans-N2O2 donor environment. Reaction of the Schiff base with nickel(II) acetate in the presence of excess pyridine leads to the formation of a similar dinuclear complex, [Ni(ONNO)(py)](2), but in this case comprises five coordinate high-spin Ni(II) ions with pyridine ligands occupying the axial coordination sites as revealed by X-ray crystallographic analysis. (c) 2005 Published by Elsevier B.V.

Macrocyclic amines as structure-directing agents for the synthesis of three-dimensional antimony-sulfide frameworks

A new family of antimony sulfides, incorporating the macrocyclic tetramine 1,4,8,11-tetraazacyclotetradecane ( cyclam), has been prepared by a hydrothermal method. [C10N4H26][Sb4S7] (1), [Ni(C10N4H24)][Sb4S7] (2), and [Co(C10N4H24)](x)[C10N4H26](1-x)[Sb4S7] (0.08 <= x <= 0.74) (3) have been characterized by single-crystal X-ray diffraction, elemental analysis, thermogravimetry, and analytical electron microscopy. All three materials possess the same novel three-dimensional Sb4S72- framework, constructed from layers of parallel arrays of Sb4S84- chains stacked at 90 to one another. In 1, doubly protonated macrocyclic cations reside in the channel structure of the antimonysulfide framework. In 2 and 3, the cyclam acts as a ligand, chelating the divalent transition- metal cation. Analytical and X-ray diffraction data indicate that the level of metal incorporation in 2 is effectively complete, whereas in 3, both metalated and nonmetalated forms of the macrocycle coexist within the structure.

Comparison Of The Solution Of Histidine-tryptophan-alfacetoglutarate With Histidine-tryptophan-glutamate As Cardioplegic Agents In Isolated Rat Hearts: An Immunohistochemical Study.

Cardiac arrest during heart surgery is a common procedure and allows the surgeon to perform surgical procedures in an environment free of blood and movement. Using a model of isolated rat heart, the authors compare a new cardioplegic solution containing histidine-tryptophan-glutamate (group 2) with the histidine-tryptophan-alphacetoglutarate (group 1) routinely used by some cardiac surgeons. To assess caspase, IL-8 and KI-67 in isolated rat hearts using immunohistochemistry. 20 Wistar male rats were anesthetized and heparinized. The chest was opened, cardioctomy was performed and 40 ml/kg of the appropriate cardioplegic solution was infused. The hearts were kept for 2 hours at 4ºC in the same solution, and thereafter, placed in the Langendorff apparatus for 30 minutes with Ringer-Locke solution. Immunohistochemistry analysis of caspase, IL-8, and KI-67 were performed. The concentration of caspase was lower in group 2 and Ki-67 was higher in group 2, both P<0.05. There was no statistical difference between the values of IL-8 between the groups. Histidine-tryptophan-glutamate solution was better than histidine-tryptophan-alphacetoglutarate solution because it reduced caspase (apoptosis), increased KI-67 (cell proliferation), and showed no difference in IL-8 levels compared to group 1. This suggests that the histidine-tryptophan-glutamate solution was more efficient than the histidine-tryptophan-alphacetoglutarate for the preservation of hearts of rat cardiomyocytes.