FREE RADICALS

Author: LEON RIZO YOLANDA MARIA DE.
Year: 2004.
University: LA LAGUNA.
Place of defense: FACULTAD DE QUIMICA.
Place of preparation: INSTITUTO DE PRODUCTOS NATURALES Y AGROBIOLOGIA DEL CSIC.

Summary: This thesis is divided into four chapters: In the first chapter examines the reaction of fragmentation of radical alcoxilo anoméricos generated from carbohydrate derivatives, treating them with reactive iodine and iodine hipervalente. These substrates presents multiple links to the CC and CN could added that the C-radical from fragmentation. The products of the reaction were generally 2-acetoxiacetales and in the case of the addendum to double bonds CC has won so stereoselective a carbociclo polioxigenado. The second chapter examines the descarboxilación of beta and gamma-amino acids, developed an effective methodology for obtaining different hetero nitrogen funcionalizados, which are useful intermediate in the synthesis of a variety of compounds. So, were synthesized analogs iminoazúcares inhibitors enzymes glicosidasas and analogues imino-C disaccharides and opiates. The reaction was also used to obtain new antifungal compounds. The third chapter has developed a method for descarboxilación of alfa-amino acids using soft conditions and passes with a good to excellent yields. The generation of intermediate N-aciliminio has been demonstrated by entrapment of the same with different nucleotide as water, alcohols, alilsilanos, enoléteres and dienos. The hetero nitrogen obtained with this method are very useful intermediate in the synthesis of analogs of bioactive alkaloids. In the fourth chapter has developed a methodology for obtaining pirrolidina and piperidinas 2,3-disustituidas from alfa-amino acid using a commercial reaction in a step descarboxilación-beta yodación-adición of nucleotide.

Author: CEREZO GUISADO MARIA ISABEL.
Year: 2005.
University: EXTREMADURA.
Place of defense: FACULTAD DE VETERINARIA.
Place of preparation: FACULTAD DE VETERINARIA.

Summary: The gradual loss of neurons specific brain through the process of apoptosis is associated with the emergence of several neurodegenerative diseases such as Parkinson's, amyotrophic lateral sclerosis or Alzheimer's disease and aging. Therefore, the process of neuronal apoptosis is the subject of numerous studies in recent years. Recent studies from our laboratory showed that the lovastatin, a competitive and reversible inhibitor of HMG-CoA reductasas, key enzyme in the path of biosynthesis of cholesterol and compounds isoprenoides, it is able to inhibit growth and induce apoptosis of neuroblastos fetal rat. Its effects are associated with a decrease in levels of prenilación of Ras proteins and RhoA, suggesting that neuronal apoptosis induced by lovastatin may be mediated by the activation or suppression of signal transduction pathways regulated by these or other protein preniladas. Therefore, the overall objective of this thesis has been deeply involved in the molecular mechanisms that control neuronal apoptosis and, in particular, consider the signal transduction pathways involved in neuronal death induced by lovastatin. Knowledge of these mechanisms affected by the lovastatin can help set the major role that the route has biosynthesis of cholesterol in the development of the nervous system. All experiments conducted in this study have been performed in a cell line neuroblastos fetal rat called E18. In particular, it has studied the major signaling pathways that regulate cell survival, routes Ras / ERKs and Pl3/PKB and the two major signaling pathways that induce cell death, routes of JNKs and p38 MAPKs. In this paper, we have shown that treatment of neuroblastos fetal rat with lovastatin, in the same condition that inhibits growth and induces neuronal apoptosis, inhibition produced by the path of survival Ras / ERKs (analyzed as a reduction in the many Ras-GTP, a decrease in the phosphorylation of kinases ERK1 and ERK2 and a decrease in the phosphorylation of the transcription factor CREB). In parallel, treatment with lovastatin produces a clear inhibition of the kinase activity of the Pl63-Ky a decrease in the phosphorylation of its main molecule efectora, kinase PKB, which consequently leads to inhibit the phosphorylation of the kinase p70S6K and the regulatory protein factor initiation of translation in eukaryotic the F4E, protein 4EBP1. Additionally, lovastatin results in a decline in the levels of expression of the protein p70S6K. At the same time, the treatment of neuroblastos with lovastatin leads to the activation of JNKs and therefore the phosphorylation of the transcription factor c-Jun, its main effector. Consequently, lovastatin produce an increase in the activity of transcription factor AP-1 and gene expression pro-apoptótico Bim. Additionally leads to the activation of caspase 3. However, treatment with lovastatin does not affect the activation of the path of p38MAPKs in neuroblastos fetal rat. Taken together our results indicate that inhibition of the two major signaling pathways regulating cell survival, ERK and Pl3-K, and the activation of the main route that controls cell death, JNK, could explain apoptosis of neuroblastos fetal lovastatin-induced rat.

Author: CARBONELL LLOPIS ESTHER JOAQUINA.
Year: 2006.
University: POLITÉCNICA DE VALENCIA.
Place of defense: Universidad Politécnica de Valencia.
Place of preparation: Universidad Politécnica de Valencia.

Summary: In this thesis has been prepared and characterized in a systematic way a new generation of photocatalysts based materials such as zeolites hosts with better benefits. Among them are 2,4,6-trifeniltiapirilio, ftalocianinas iron and aggregates containing titanium dioxide modifiers introducing absorption bands in the visible. The preparation of these materials was carried out by synthesis "boat in the bottle" (2,4,6-trifeniltiapirilio and ftalocianinas iron) and ion exchange and adsorption followed by hydrolysis of ligand (aggregates of titanium dioxide). Among the materials prepared those where 2,4,6-trifeniltiapirilio is encapsulated in zeolite beta I have demonstrated the increased activity, being far superior to the titanium dioxide P-25 when irradiation is conducted through the Pyrex. Therefore, these materials are promising because of its high activity and the possibility of introducing selective way in the photocatalyst.