77 resultados para platinum derivative
em Consorci de Serveis Universitaris de Catalunya (CSUC), Spain
Resumo:
The complex etiology of schizophrenia has prompted researchers to develop clozapine-related multitargetstrategies to combat its symptoms. Here we describe a series of new 6-aminomethylbenzofuranones in aneffort to find new chemical structures with balanced affinities for 5-HT2 and dopamine receptors. Throughbiological and computational studies of 5-HT2A and D2 receptors, we identified the receptor serine residuesS3.36 and S5.46 as the molecular keys to explaining the differences in affinity and selectivity betweenthese new compounds for this group of receptors. Specifically, the ability of these compounds to establishone or two H-bonds with these key residues appears to explain their difference in affinity. In addition, wedescribe compound 2 (QF1004B) as a tool to elucidate the role of 5-HT2C receptors in mediating antipsychoticeffects and metabolic adverse events. The compound 16a (QF1018B) showed moderate to high affinitiesfor D2 and 5-HT2A receptors, and a 5-HT2A/D2 ratio was predictive of an atypical antipsychotic profile.
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We see that the price of an european call option in a stochastic volatilityframework can be decomposed in the sum of four terms, which identifythe main features of the market that affect to option prices: the expectedfuture volatility, the correlation between the volatility and the noisedriving the stock prices, the market price of volatility risk and thedifference of the expected future volatility at different times. We alsostudy some applications of this decomposition.
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Epitaxial films of the biferroic YMnO3 (YMO) oxide have been grown on platinum-coated SrTiO3(1 1 1) and Al2O3(0 0 0 1) substrates. The platinum electrodes, (1 1 1) oriented, are templates for the epitaxy of the hexagonal phase of YMO with a (0 0 0 1) out-of-plane orientation, which is of interest as this is the polarization direction of YMO. X-ray diffractometry indicates the presence of two crystal domains, 60° rotated in-plane, in the Pt(1 1 1) layers which subsequently are transferred on the upperlaying YMO. Cross-section analysis by high-resolution transmission electron microscopy (HRTEM) of YMnO3/Pt/SrTiO3(1 1 1) shows high-quality epitaxy and sharp interfaces across the structure in the observed region. We present a detailed study of the epitaxial growth of the hexagonal YMO on the electrodes.
Resumo:
Purpose. The aim of this study was to identify new surfactants with low skin irritant properties for use in pharmaceutical and cosmetic formulations, employing cell culture as an alternative method to in vivo testing. In addition, we sought to establish whether potential cytotoxic properties were related to the size of the counterions bound to the surfactants. Methods. Cytotoxicity was assessed in the mouse fibroblast cell line 3T6, and the human keratinocyte cell line NCTC 2544, using the MTT assay and uptake of the vital dye neutral red 24 h after dosing (NRU). Results. Lysine-derivative surfactants showed higher IC50s than did commercial anionic irritant compounds such as sodium dodecyl sulphate, proving to be no more harmful than amphoteric betaines. The aggressiveness of the surfactants depended upon the size of their constituent counterions: surfactants associated with lighter counterions showed a proportionally higher aggressivity than those with heavier ones. Conclusions. Synthetic lysine-derivative anionic surfactants are less irritant than commercial surfactants such as sodium dodecyl sulphate and Hexadecyltrimethylammonium bromide and are similar to Betaines. These surfactants may offer promising applications in pharmaceutical and cosmetic preparations, representing a potential alternative to commercial anionic surfactants as a result of their low irritancy potential.
Resumo:
The study of the reactivity of three 1-(2-dimethylaminoethyl)-1H-pyrazole derivatives of general formula [1-(CH2)2NMe2}-3,5-R2-pzol] {where pzol represents pyrazole and Rdouble bond; length as m-dashH (1a), Me (1b) or Ph (1c)} with [MCl2(DMSO)2] (Mdouble bond; length as m-dashPt or Pd) under different experimental conditions allowed us to isolate and characterize cis-[M{κ2-N,N′-{[1-(CH2)2NMe2}-3,5-R2-pzol])}Cl2] {MMdouble bond; length as m-dashPtPt (2a-2c) or Pd (3a-3c)} and two cyclometallated complexes [M{κ3-C,N,N′-{[1-(CH2)2NMe2}-3-(C5H4)-5-Ph-pzol])}Cl] {Mdouble bond; length as m-dashPt(II) (4c) or Pd(II) (5c)}. Compounds 4c and 5c arise from the orthometallation of the 3-phenyl ring of ligand 1c. Complex 2a has been further characterized by X-ray crystallography. Ligands and complexes were evaluated for their in vitro antimalarial against Plasmodium falciparum and cytotoxic activities against lung (A549) and breast (MDA MB231 and MCF7) cancer cellular lines. Complexes 2a-2c and 5c exhibited only moderate antimalarial activities against two P. falciparum strains (3D7 and W2). Interestingly, cytotoxicity assays revealed that the platinacycle 4c exhibits a higher toxicity than cisplatin in the three human cell lines and that the complex 2a presents a remarkable cytotoxicity and selectivity in lung (IC50 = 3 μM) versus breast cancer cell lines (IC50 > 20 μM). Thus, complexes 2c and 4c appear to be promising leads, creating a novel family of anticancer agents. Electrophoretic DNA migration studies in presence of the synthesized compounds have been performed, in order to get further insights into their mechanism of action.
Resumo:
The members of the epidermal growth factor (EGF)/ErbB family are prime targets for cancer therapy. However, the therapeutic efficiency of the existing anti-ErbB agents is limited. Thus, identifying new molecules that inactivate the ErbB receptors through novel strategies is an important goal on cancer research. In this study we have developed a shorter form of human EGF (EGFt) with a truncated C-terminal as a novel EGFR inhibitor. EGFt was designed based on the superimposition of the three-dimensional structures of EGF and the Potato Carboxypeptidase Inhibitor (PCI), an EGFR blocker previously described by our group. The peptide was produced in E. coli with a high yield of the correctly folded peptide. EGFt showed specificity and high affinity for EGFR but induced poor EGFR homodimerization and phosphorylation. Interestingly, EGFt promoted EGFR internalization and translocation to the cell nucleus although it did not stimulate the cell growth. In addition, EGFt competed with EGFR native ligands, inhibiting the proliferation of cancer cells. These data indicate that EGFt may be a potential EGFR blocker for cancer therapy. In addition, the lack of EGFR-mediated growth-stimulatory activity makes EGFt an excellent delivery agent to target toxins to tumours over-expressing EGFR.
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A straightforward synthesis of the Met antagonist JLK1360 involving an alkylationcyclocondensation process using aminothiazole 1 and nitrophenacyl bromide 2, reduction of the nitro group, and coupling of the resulting tetracyclic aniline 5 with an appropriate N-acyl alanine derivative, is reported.
Resumo:
A straightforward synthesis of the Met antagonist JLK1360 involving an alkylationcyclocondensation process using aminothiazole 1 and nitrophenacyl bromide 2, reduction of the nitro group, and coupling of the resulting tetracyclic aniline 5 with an appropriate N-acyl alanine derivative, is reported.
Resumo:
The use of ionic liquid analogues as solvents has increased in order to substitute the aqueous solvents in some applications in which the side reactions are undesirable. However these solvents prepared from the mixture in the eutectic proportion of species establishing hydrogen bonds are susceptible of electrochemical reactions. The study of platinum deposition on vitreous carbon in an ionic liquid analogue (2 urea: choli ne chloride) is presented; the electrochemical study has permitted to interpret the sequence of the metal deposition process and simultaneously to analyze the behavior of the ionic liquid analogue along the process. Reduction reactions of the solvent relat ed both to the electronation of choline and hydrogen formation have been detected. Different substrata have been used in order to test the possibility and the extent of these reactions depending on the nature of material. The results indicate that the feas ible electrochemical window of the substrate/solvent is highly dependent of the kind of substrate; the negative limit is tied by the massive hydrogen reaction, reaction enhanced by the electrocatalytic character of the substrate.
Resumo:
In this paper we obtain the necessary and sufficient conditions for embedding results of different function classes. The main result is a criterion for embedding theorems for the so-called generalized Weyl-Nikol'skii class and the generalized Lipschitz class. To define the Weyl-Nikol'skii class, we use the concept of a (λ,β)-derivative, which is a generalization of the derivative in the sense of Weyl. As corollaries, we give estimates of norms and moduli of smoothness of transformed Fourier series.
Resumo:
The presence of subcentres cannot be captured by an exponential function. Cubic spline functions seem more appropriate to depict the polycentricity pattern of modern urban systems. Using data from Barcelona Metropolitan Region, two possible population subcentre delimitation procedures are discussed. One, taking an estimated derivative equal to zero, the other, a density gradient equal to zero. It is argued that, in using a cubic spline function, a delimitation strategy based on derivatives is more appropriate than one based on gradients because the estimated density can be negative in sections with very low densities and few observations, leading to sudden changes in estimated gradients. It is also argued that using as a criteria for subcentre delimitation a second derivative with value zero allow us to capture a more restricted subcentre area than using as a criteria a first derivative zero. This methodology can also be used for intermediate ring delimitation.
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La 3,4-Metilendioximetanfetamina (MDMA, éxtasis) es un derivado anfetamínico sintético ampliamente usado como droga recreativa, que produce neurotoxicidad serotonérgica en animales y posiblemente también en humanos. El mecanismo subyacente de neurotoxicidad, incluye la formación de especies reactivas de oxigeno (ROS), pero la fuente de generación de estos es un punto de controversia. Se postula que la neurotoxicidad inducida por la MDMA es mediada por la formación de metabolitos bioreactivos. Específicamente, los metabolitos primarios de tipo catecol, la 3,4- dihidroximetanfetamina (HHMA) y la 3,4-dihidroxianfetamina (HHA), que luego dan lugar a la formación de conjugados con el glutatión y la N-acetilcisteína, y que conservan la capacidad de entrar en el ciclo redox y presentan neurotoxicidad serotonérgica en ratas. Aunque la presencia de dichos metabolitos se demostró recientemente en microdialisados de cerebros de ratas, su formación en humanos no se ha reportado aun. Este trabajo describe la detección de N-acetil-cisteína-HHMA (NAC-HHMA) y N-acetil-cisteína-HHA (NAC-HHA) en orina humana de 15 consumidores recreacionales de MDMA (1.5 mg/kg) en un entorno controlado. Los resultados revelan que en las primeras 4 horas después del consumo de MDMA aproximadamente el 0.002% de la dosis administrada es recuperada como aductos tioéter. Los polimorfismos genéticos en la expresión de las enzimas CYP2D6 y COMT, que en conjunto son las principales determinantes de los niveles estables de HHMA y HHA, posiblemente expliquen la variabilidad interindividual observada en la recuperación de la NAC-HHMA y la NAC-HHA en orina. Resumiendo, por primera vez se demuestra la formación de aductos tioéteres neurotóxicos de la MDMA en humanos. Estos resultados apoyan la hipótesis de que la bioactivación de la MDMA a metabolitos neurotóxicos es el mecanismo relevante para la generación de la neurotoxicidad en humanos.
Resumo:
La recerca, que ha durat quatre anys (2004-2008), s’ha centrat en l’estudi del parlar salat, un subdialecte del català oriental que es caracteritza per una sola isoglossa: l’ús de l’article salat (es, sa), és a dir, l’element derivat del demostratiu llatí “ipse”. Aquesta varietat ―poc estudiada― no té un abast gaire definit. Se sol situar en una estreta franja del litoral de Girona, entre Blanes i Begur, i que, després, isoladament, reapareix a Cadaqués, on es manté amb més vigència. A banda que els estudis no estableixen els límits geogràfics del fenomen de manera precisa, es tenen indicis que el tret que defineix i dóna nom a la varietat es troba en un acusat procés de recessió i de pèrdua, ja que només l’empren persones d’edat avançada (en general, pescadors). La tesi concreta l’estat actual del parlar salat. També fixa la cronologia del canvi de l’article salat (és a dir, en quin moment s’ha substituït per l’article literari, el, la) i es decriuen els factors que l’han propiciat (migració, turisme, la pressió de l’estàndard, etc.). El parlar salat és un exemple de desdialectalització del català, atès que es verifica que el tret que el caracteritza va començar a caure en desús en dels anys cinquanta del segle passat i que, avui dia, pràcticament ja s’ha extingit (només es manté en parlants de Cadaqués nascuts després de 1983). Per tant, s’evidencia que cal replantejar-se l’actual divisió dialectal de la llengua catalana ja que el subdialecte estudiat no existeix.
Resumo:
New sufficient conditions for representation of a function via the absolutely convergent Fourier integral are obtained in the paper. In the main result, Theorem 1.1, this is controlled by the behavior near infinity of both the function and its derivative. This result is extended to any dimension d &= 2.