Farmacología clínica de la metilenodioximetanfetamina (MDMA, éxtasis) tras su administración a dosis repetidas

Consultable des del TDXTítol obtingut de la portada digitalitzadaEl consumo de 3,4-metilendioximetanfetamina (MDMA o éxtasis) se realiza habitualmente en ambientes festivos y es frecuente el uso de varias dosis a lo largo de una noche de fiesta. En la literatura científica no se han descrito hasta la fecha estudios controlados a dosis repetidas de MDMA que permitan vislumbrar sí con el consumo repetido de esta sustancia aparecen fenómenos de tolerancia o sensibilidad que puedan favorecer la presentación de toxicidad. El objetivo de esta Tesis fue conocer la farmacología de la MDMA tras la administración de dos dosis consecutivas de MDMA separadas por un intervalo de cuatro horas, profundizando especialmente en su farmacocinética y en la posible aparición de fenómenos de tolerancia aguda. Se diseñó un ensayo clínico a doble ciego, cruzado, controlado con placebo, con asignación aleatoria de las condiciones de tratamiento según un cuadrado latino de 4x4 balanceado. Participaron un total de ocho voluntarios sanos consumidores habituales de MDMA. Cada sujeto participo en cuatro sesiones, una para cada condición de tratamiento, separadas por al menos una semana de periodo de blanqueo. Las cuatro condiciones de tratamiento fueron: MDMA 100 mg + placebo (MDMA primera administración); placebo + MDMA 100 mg (MDMA segunda administración), MDMA 100 mg + MDMA 100 mg (MDMA dosis múltiple) y placebo + placebo (Placebo). Tras la administración repetida se observaron aumentos significativos de la presión arterial sistólica, la frecuencia cardiaca y la temperatura respecto a la dosis única. Estos aumentos no alcanzaron los esperables por el principio de superposición o suma simple de los efectos de las dos dosis. En el caso de la presión arterial diastólica la segunda administración de la dosis múltiple registró aumentos similares a los esperados por superposición. Ello sugiere que podría existir tolerancia aguda en algunas de estas variables. El rendimiento psicomotor y la tensión muscular medida por la esoforia en el ala de Maddox mostraron cambios significativos respecto a la dosis única. Los incrementos fueron incluso mayores de los esperables por el principio de superposición tras la dosis repetida. No parece existir tolerancia, y en el caso de la tensión muscular podría incluso existir una posible sensibilización. En el caso de los efectos subjetivos, la dosis repetida produjo globalmente incrementos mayores que la dosis única en las escalas de euforia, estimulación, efectos desagradables y cambios en las percepciones. En el caso de los efectos de euforia y estimulación fueron parecidos a los previstos según el principio de superposición. En ningún caso se presentaron alucinaciones ni síntomas sugestivos de alteraciones psicóticas. Las concentraciones plasmáticas de cortisol y prolactina tras la dosis repetida fueron similares a las obtenidas tras una dosis única, sugiriendo tolerancia. La concentración plasmática máxima de la MDMA tras la segunda administración de la dosis repetida superó en un 20% la que hubiera sido esperable por la suma de las dos dosis administradas. En cuanto a la concentración de HMMA, prácticamente no aumentó tras la segunda dosis, observándose niveles similares a los obtenidos tras una dosis única y por ello un 45 % menores de los esperados. La formación de la HMMA parece inhibirse por la presencia previa de MDMA y/o sus metabolitos. Integrando los efectos farmacológicos y las concentraciones plasmáticas de MDMA, se observa una clara tolerancia aguda en todas las variables estudiadas excepto para la tensión muscular y el rendimiento psicomotor. La administración de dos dosis consecutivas de MDMA produce una cierta acumulación en las concentraciones plasmáticas de MDMA pero globalmente los efectos farmacológicos son menores de los esperables para esas elevadas concentraciones. Todo ello sugiere la aparición de un fenómeno de tolerancia aguda, que posiblemente es de origen farmacodinámico.3,4-methylenedioxymethamphetamine (MDMA, ecstasy) is usually consumed in multiple doses along a party session. Till now there aren't published controlled clinical trial after repetated administration looking for the presentation of acute tolerance or up-regulation that implies toxicity. The goal of this thesis was know the pharmacology of MDMA after repeated administration with an interval of four hours between doses considering pharmacokinetic and the possibility of acute tolerance. The study design was double-blind, randomized, crossover, and controlled. Treatment conditions were randomly using a balanced 4x4 Latin -square design. Eight healthy male recreational MDMA users participated in four sessions with a 1-week washout period. They were administered twice with a 4 hours interval on each of four experimental sessions. Drug conditions were: MDMA 100mg+ placebo(MDMA first dose), placebo+ MDMA 100mg (MDMA second dose), MDMA 100mg+MDMA 100mg (MDMA repeated administration) and placebo+ placebo (placebo). Repeated administration significantly increased sistolic blood presure, heart rate and temperature as compared with the first administration. These increases didn't reach the expected by the superposition criteria. The diastolic blood presure after the second administration increased like the expected by superposition criteria. There were acute tolerance in some of these physiological variables. Psychomotor performance and muscular tension measured by the esoforia in the Maddox -wing increased more than expected considering the pharmacokinetic superposition criteria. Maddox-wing and psychomotor tasks seemed not to be affected by acute tolerance and in the Maddox -wing probably there were a up-regulation phenomenon. Subjective effects after the repeated administration were increased more as compared with the first administration in scales related to euphoria, stimulated, bad effects and changes in perceptions. The effects related to euphoria and stimulated were similar with the expected by the superposition criteria. No hallucinations or psychotic episodes were observed among subjects during the study. Plasma concentrations of cortisol and prolactina after the repeated administration were similar as compared with the concentrations after the first administration, this suggested the development of tolerance. Peak concentration of MDMA after the second administration of the repeated administration was 20% higher than the expected by the superposition criteria. Peak concentration of HMMA after the repeated administration was 45% lower than the expected, this metabolite maybe inhibited by his precursor MDMA or their metabolites. In summary, the pharmacologic effects observed in relation with the plasma concentrations of MDMA, suggested the development of almost complete tolerance for all the variables essayed except Maddox-wing and psicomotor performance. Repeated administration of MDMA made plasma accumulation of MDMA but the pharmacologic effects were fewer than expected by these higher concentrations. All of this suggested the development of acute tolerance maybe pharmacodynamic

On the mechanism of phenolic formylation mediated by TiCl4 complexes: existence of diradical intermediates induced by valence tautomerism

The conventional electrophilic intramolecular aromatic substitution pathway proposed by Cresp et al. [J. Chem. Soc., Perkin Trans. 1 1973, 340 345] is confirmed by the observed products of phenolic formylation mediated by TiCl4. However, when the nucleophilic path is quenched by appropriate ligand modification, the initial equilibria between the possible neutral complexes of TiCl4 with 3,5-dimethoxy-phenol and/or diethyl ether lead to different stable diradical intermediates induced by valence tautomerism that provide valuable activated reagents. Some of these species have been detected by EPR, characterized theoretically and captured by TEMPO, thus providing a consistent mechanism for the reaction with one or more equivalents of TEMPO per phenol

Identification of a novel allosteric inhibitory site on tryptophan hydroxylase 1 enabling unprecedented selectivity over all related hydroxylases

Pulmonary arterial hypertension (PAH) has demonstrated multi-serotonin receptor dependent pathologies, characterized by increased tone (5-HT1B receptor) and complex lesions (SERT, 5-HT1B, 5-HT2B receptors) of the pulmonary vasculature together with right ventricular hypertrophy, ischemia and fibrosis (5-HT2B receptor). Selective inhibitors of individual signaling elements – SERT, 5-HT2A, 5HT2B, and combined 5-HT2A/B receptors, have all been tested clinically and failed. Thus, inhibition of tryptophan hydroxylase 1 (TPH1), the rate limiting step in 5-HT synthesis, has been suggested as a more broad, and thereby more effective, mode of 5-HT inhibition. However, selectivity over non-pathogenic enzyme family members, TPH2, phenylalanine hydroxylase, and tyrosine hydroxylase has hampered therapeutic development. Here we describe the site/sequence, biochemical, and biophysical characterization of a novel allosteric site on TPH1 through which selectivity over TPH2 and related aromatic amino acid hydroxylases is achieved. We demonstrate the mechanism of action by which novel compounds selectively inhibit TPH1 using surface plasma resonance and enzyme competition assays with both tryptophan ligand and BH4 co-factor. We demonstrate 15-fold greater potency within a human carcinoid cell line versus the most potent known TPH1/2 non-specific inhibitor. Lastly, we detail a novel canine in vivo system utilized to determine effective biologic inhibition of newly synthesized 5-HT. These findings are the first to demonstrate TPH1-selective inhibition and may pave the way to a truly effective means to reduce pathologic 5-HT and thereby treat complex remodeling diseases such as PAH

Novel Cinnamyl Hydroxyamides and 2-Aminoanilides as Histone Deacetylase Inhibitors: Apoptotic Induction and Cytodifferentiation Activity

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Molecular characterization of EGFR, PDGFRA and VEGFR2 in cervical adenosquamous carcinoma

<p>Abstract</p> <p>Background</p> <p>Adenosquamous carcinoma of the uterine cervix is an infrequent but aggressive subtype of cervical cancer. A better understanding of its biological behaviour is warranted to define more accurate prognosis and therapeutic targets. Currently, the blockage of receptor tyrosine kinase (RTKs) activity is an efficient therapeutic strategy for many different cancers. The objective of this study was to investigate EGFR, PDGFRA and VEGFR2 RTKs overexpression and activating gene mutations in a cohort of 30 adenosquamous carcinomas of the uterine cervix.</p> <p>Methods</p> <p>EGFR, PDGFRA and VEGFR2 immunohistochemistry was performed in all samples, followed by DNA isolation from the gross macroscopically dissection of the neoplastic area. Screening for <it>EGFR </it>(exons 18–21) and <it>PDGFRA </it>(exons 12, 14 and 18) mutations was done by PCR – single-strand conformational polymorphism (PCR-SSCP).</p> <p>Results</p> <p>Despite the presence of EGFR immunohistochemical positive reactions in 43% (13/30) of the samples, no <it>EGFR </it>activating mutations in the hotspot region (exons 18–21) were identified. A silent base substitution (CAG>CAA) in <it>EGFR </it>exon 20 at codon 787 (Q787Q) was found in 17 cases (56%). All PDGFRA immunohistochemical reactions were positive and consistently observed in the stromal component, staining fibroblasts and endothelial cells, as well as in the cytoplasm of malignant cells. No activating <it>PDGFRA </it>mutations were found, yet, several silent mutations were observed, such as a base substitution in exon 12 (CCA>CCG) at codon 567 (P567P) in 9 cases and in exon 18 (GTC>GTT) at codon 824 (V824V) in 4 cases. We also observed the presence of base substitutions in intron 14 (IVS14+3G>A and IVS14+49G>A) in two different cases, and in intron 18 (IVS18-50insA) in 4 cases. VEGFR2 positivity was observed in 22 of 30 cases (73.3%), and was significantly associated with lack of metastasis (<it>p </it>= 0.038).</p> <p>Conclusion</p> <p>This is the most extensive analysis of EGFR, PDGFRA and VEGFR2 in cervical adenosquamous carcinomas. Despite the absence of <it>EGFR </it>and <it>PDGFRA </it>activating mutations, the presence of overexpression of these three important therapeutic targets in a subset of cases may be important in predicting the sensitivity of adenosquamous carcinoma to specific anti-RTKs drugs.</p

EGCG Enhances the Therapeutic Potential of Gemcitabine and CP690550 by Inhibiting STAT3 Signaling Pathway in Human Pancreatic Cancer

Background: Signal Transducer and Activator of Transcription 3 (STAT3) is an oncogene, which promotes cell survival, proliferation, motility and progression in cancer cells. Targeting STAT3 signaling may lead to the development of novel therapeutic approaches for human cancers. Here, we examined the effects of epigallocathechin gallate (EGCG) on STAT3 signaling in pancreatic cancer cells, and assessed the therapeutic potential of EGCG with gemcitabine or JAK3 inhibitor CP690550 (Tasocitinib) for the treatment and/or prevention of pancreatic cancer. Methodology/Principal Findings: Cell viability and apoptosis were measured by XTT assay and TUNEL staining, respectively. Gene and protein expressions were measured by qRT-PCR and Western blot analysis, respectively. The results revealed that EGCG inhibited the expression of phospho and total JAK3 and STAT3, STAT3 transcription and activation, and the expression of STAT3-regulated genes, resulting in the inhibition of cell motility, migration and invasion, and the induction of caspase-3 and PARP cleavage. The inhibition of STAT3 enhanced the inhibitory effects of EGCG on cell motility and viability. Additionally, gemcitabine and CP690550 alone inhibited STAT3 target genes and synergized with EGCG to inhibit cell viability and induce apoptosis in pancreatic cancer cells. Conclusions/Significance: Overall, these results suggest that EGCG suppresses the growth, invasion and migration of pancreatic cancer cells, and induces apoptosis by interfering with the STAT3 signaling pathway. Moreover, EGCG furthe

Linkers for bioconjugation

[eng] Cancer is a heterogeneous disease that represents one of the principal causes of mortality in developed countries. Due to the social and economic implications of this pathology, tremendous efforts have been making over the past decades to improve available therapeutic options to tackle this illness. Although a large number of potent chemotherapeutic agents have been identified and successfully used in clinical practice, the development of new anticancer chemotherapeutic drugs with higher antitumor efficacy and less toxicity remains as a research challenge. Current advances in the mechanistic understanding of the molecular drivers of malignancy have led to many anticancer drugs, which are targeted directly at the cancerous cells and not the neighbouring healthy cells. Thus, in order to enhance the efficacy of existing anticancer agents, several drug delivery approaches have been developed. Appropriately, ADCs strategy consists on bind determinate cell-killing drug to a monoclonal antibody (mAb) through a specific linker. Due to their high-binding specificity for tumor-specific antigens, mAb can be used as vehicles to target cell- killing payloads to tumor cells. Accordingly, two kinds of linkers are suitable to attach the payload to the antibody. On one hand, non-cleavable linkers afford and stable binding between the drug and the antibody, and alternatively, the drug could be released in the proximity or even inside of affected cells using cleavable linkers. Based on the potential of ADCs as prodrugs, our main goal is develop linkers, which could promote the drug release close to the affected tumor cells. Taking into account that connection between the antibody and the cytotoxic agent has significant effects on the selectivity, pharmacokinetics and therapeutic index of the ADC an efficient binding is needed. Therefore, the properties of a successful linker can be split up into different modules that have been combined to form an effective bridge between the cytotoxic payload and the carrier antibody. In the present thesis, we focus on the development of new linkers for bioconjugation and more specifically for Antibody–Drug conjugates (ADCs). With this purpose in mind, a conscious design of the linkers for ADCs has to be done. In the present thesis, different cleavable (Chapter 1) and non-cleavable (Chapter 2) linkers are studied and it will be explained in detail along the thesis. As a consequence, the design has to be focused on linkers stables in systemic circulation. Additionally, cleavable linkers should be unstable in tumor cells environment, such as high concentration of glutathione, highest acidic concentration, and enzymatic cleavage, among others as above-mentioned. These conditions should allow, chemically or enzymatically, the release of the drug from the carrier (antibody- linker). On one hand, the systems studied in chapter I involve N-alkylated dialkylglycines and the tetrahydropyran moiety as cleavable Linkers. On the other hand in chapter II, the mesitylene ring and perfluoroarylated compounds were studied as non-cleavable linkers for bioconjugation. The present thesis include and extensive study regarding both cleavable and non-cleavable linker. Particularly, the preparation and chemical modification of the handles in order to test and optimize the bioconjugation step. Also an interesting study was carried out in order to determine how the bioconjugation step affect to the macromolecular entities. Specifically we focus on the conjugation to antibodies and how the covalent binding of the studied linkers affect to the antigen- antibody bind affinity.[spa] El cáncer está considerado como una de las principales causas de mortalidad a nivel mundial. Y ello conlleva elevados esfuerzos socio-económicos para tratar y curar esta enfermedad a pesar de disponer un amplio número de agentes anticancerígenos descritos, la obtención de nuevos agentes terapéuticos con mejor eficacia y menores efectos secundarios continua siendo a día de hoy, un reto científico a lograr. Con el fin de mejorar estos tratamientos, se han desarrollado diversos sistemas de liberación controlada de fármacos. Un ejemplo interesante son, los sistemas conocidos como ADCs (Antibody-Drug Conjugates) que consisten en la unión de un fármaco a un anticuerpo para permitir direccionar el fármaco a célula diana. Dicha unión fármaco-anticuerpo se produce mediante un conector o linker que pueden ser no hidrolizables (Non-cleavable linkers) o hidrolizables (Cleavable Linkers). La presente tesis centra su objeto de estudio en el diseño de conectores tanto hidrolizables como no hidrolizables. En el primer capítulo de la presente Tesis se abordó la utilización de α, α-dialquilglicinas N-alquiladas como posibles conectores hidrolizables para bioconjugación. Este tipo de sistemas tipo 1,4-dicarbonílicos, presentan acidólisis de la amida del extremo C- terminal. Otro sistema estudiado como conector están basados en los enlaces tipo acetal, tioacetal y aminal sobre el anillo de tetrahidropirano. Fruto del estudio de el anillo de tetrahidropirano como conector, se estudio la aplicabilidad de este tipo de anillo como grupo protector del tiol de la cisteína para la síntesis de péptidos de fase sólida. En el segundo capitulo se abordó el estudio de conectores no hidrolizables con potencial aplicabilidad den bioconjugación. En primer lugar se estudiaron los compuestos aromáticos tipo mesitileno utilizando los precursores dibromados para la formación de tioeteres estables a partir de dos cisteínas en péptidos, proteínas y anticuerpos. Además en este mismo capítulo se emprendió la unión de compuestos perfluorados en bioconjugación

Model tridimensional de la Parroquia de Sant Ramon Nonat

L’ objectiu principal d’aquest projecte, és obtenir el model tridimensional de la parròquia de Sant Ramon Nonat de Collblanc , emprant les tècniques clàssiques de topografia i de fotogrametria terrestre (rectificació i restitució). Durant tots els anys de formació acadèmica a la Facultat he tingut l’oportunitat de fer una sèrie de pràctiques basades en la fotogrametria. Des de el començament ha sigut un tema que m’ha interessat . Per culpa de la falta de temps i la massificació de les classes , no havia tingut l’oportunitat de profunditzar més en aquest terreny, per tant un altre objectiu, és ara agafar experiència en un mètode poc practicat durant la carrera i així obtenir uns coneixements més amplis sobre fotogrametria i en especial el cas terrestre. Un altre objectiu era poder facilitar el model tridimensional a la Parròquia de Sant Ramon , a través d’un conveni, per a que tinguessin una documentació gràfica real de l’edifici, però la meva idea no els va interessar des de un principi per tant no serà subministrat a cap entitat. També espero que la realització d’aquest projecte hem serveixi en la meva actual i futura vida laboral, com ha experiència en aquest camp de la topografia, que encara no havia desenvolupat, així com en l’utilització dels diferents programes informàtics emprats en aquest treball