Made available in DSpace on 2014-06-12T18:05:01Z (GMT). No. of bitstreams: 2 arquivo7226_1.pdf: 421955 bytes, checksum: 579902969dede05f55174abd1bd418d2 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2006 / O modelo de regressão Beta possui grande aplicabilidade prática, em particular, na modelagem de taxas e proporções e, tal como nos demais modelos de regressão, também são requeridos métodos que determine qual o melhor modelo. A presente dissertação tem como objetivo principal implementar e avaliar o desempenho de diferentes critérios de seleção de modelos para o modelo de regressão Beta. Para tal, mediante diferentes estudos de simulações de Monte Carlo, analisamos alguns critérios selecionados levando em consideração suas propriedades assintóticas, os quais foram obtidos por meio da função de máxima verossimilhança. Os resultados das simulações revelaram que os desempenhos dos referidos critérios dependem da especificação do modelo e também do tamanho da amostra. Apresentamos ainda uma aplicação relacionada ao índice de Desenvolvimento Humano, que é uma variável adequada à modelagem em estudo, visto que seus valores variam no intervalo (0,1). Nesta aplicação, observamos que com a amostra de todos os municípios da região Nordeste os diferentes critérios utilizados selecionaram o mesmo modelo

Orientador: Telma Teixeira Franco / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-07-25T10:33:54Z (GMT). No. of bitstreams: 1 Silva_MariaEstelada_D.pdf: 6869313 bytes, checksum: e25d368e00276aa7116f957184aa768c (MD5) Previous issue date: 1999 / Resumo: Este trabalho visou estudar o emprego de ligantes de afinidade para extração e purificação de diferentes enzimas por partição em sistemas de duas fases aquosas (SDF A). O emprego de ligantes específicos em um estágio inicial de um processo extrativo visa reduzir o número de etapas do mesmo, pois ao aumentar a seletividade e especificidade de uma operação, as próximas são diretamente beneficiadas pela redução de carga do material contaminante. Inicialmente foram investigados métodos de ativação química do polietilenoglicol (PEG) com o intuito de torná-lo mais reativo para o acoplamento da molécula do ligante. Foram usados dois métodos de ativação deste polímero: com cloreto de tresila e com cloreto de tionila. Para ativação com cloreto de tresila, o rendimento obtido foi de 74%, determinado pela análise do enxofre elementar, enquanto que para a ativação com cloreto de tionila, o rendimento obtido foi de 86% (p/p) (capítulo 7). Um estudo para extração e recuperação da f3-galactosidase de diferentes origens microbianas: Kluyveromyces lactis, Kluyveromyces fragilis, Aspergillus oryzae e Escherichia co/i foi então realizado (capítulo 3) e foi observado que somente a 13galactosidase de Escherichia coli era coletada na fase superior em sistema formado por PEG 4000 15% e fosfato 13,6% (coeficiente de partição, K = 52). As demais 13galactosidases eram sempre particionadas em direção à fase inferior salina juntamente com as principais proteínas contaminantes, impossibilitando a separação e purificação. Com o objetivo de separar a f3-galactosidase das outras proteínas, um processo específico de partição por afinidade foi desenvolvido, o qual consistiu de duas etapas: acoplamento específico da enzima ao ligante e rompimento desta interação. Para eficiente separação entre a f3-galactosidase de Kluyveromyces fragilis e os contaminantes protéicos foi desenvolvido um processo em duas etapas, aonde a primeira utiliza o ligante APGP (paminofenil-f3-D-tiogalactopiranosídeo). Os sistemas usados foram formados, na primeira etapa (acoplamento da enzima), por PEG 4000-APGP 6% e dextrana 505.000 8% e na segunda etapa (desacoplamento da enzima) por PEG-APGP 13% e fosfato 9%. Na primeira etapa de purificação, o K da ?-galactosidase teve um aumento de aproximadamente 2.800 vezes com o uso do PEG-APGP, apresentando recuperação de 55% da enzima na fase polimérica do sistema PEG-APGP/dextrana e a segunda etapa da purificação da enzima foi realizada em sistema formado por PEG-APGP 13% e fosfato 9%. mostrando-se altamente eficiente na reversão do K da enzima ?-galactosidase para a fase oposta. O valor do coeficiente de partição foi de 2,2 x 10-5 com 39% de recuperação da enzima na fase salina (capítulos 3 e 4). Com o intuito de investigar a capacidade do polímero de afinidade PEG-IDA-CU2+ em extrair proteínas nos SDF A, a partição da lisozima proveniente de clara de ovo e da peroxidase de soja foi investigada (capítulos 5 e 6). A lisozima de clara de ovo de galinha foi utilizada como enzima modelo nos estudos preliminares em sistemas de afinidade contendo o complexo PEG-IDA-Cu2+. Esta enzima possui um resíduo de histidina disponível na sua superfície, tornando viável sua extração neste tipo de sistema, já que um resíduo de histidina é suficiente para formar o complexo enzima-metalo-ligante. As concentrações empregadas foram de PEG 4000 13% e fosfato de potássio 9% (p/p), pH 7,0 nos SDF A sem o ligante. Em sistemas de afinidade, as concentrações do PEG-IDA-Cu2+ foram de 1, 5 e 10% e as concentrações de PEG 4000 foram de 12, 8 e 3%, respectivamente, sendo que a concentração do fosfato permaneceu em 9%. O valor do coeficiente de partição, K, foi aumentado 9 vezes quando PEG-IDA-Cu2+ foi usado nos SDF A de afinidade, sendo possível recuperar 51 % da lisozima. Para recuperação da peroxidase de soja, Glycine max, o metalo-ligante cobre (Cu2l foi acoplado ao complexo PEG-IDA, formador da fase polimérica do sistema. Duas etapas foram suficientes para a recuperação da peroxidase usando sistemas de afinidade. Na primeira etapa da extração, o sistema foi composto por PEG-IDA-CU2+ 14% e sulfato de sódio 8% para o acoplamento da enzima e na segunda etapa, um sistema constituído de PEG-IDA-CU2+ 14% e fosfato 10% foi usado para o desacoplamento da enzima, a qual foi recuperada na fase salina. Obteve-se um aumento de K de 24 vezes e recuperação maior que 109% da enzima, quando o sistema de afinidade foi usado. Na etapa de desacoplamento da enzima obteve-se 64% de recuperação. A fase polimérica foi recic1ada e usada num sistema contendo PEG-IDA-Cu2+ 14% e sulfato de sódio 8%, obtendo-se um K = 23, com recuperação de 85% da peroxidase / Abstract: In this work the extraction and purification of f3-galactosidase from different species and soybean peroxidase (Glycine max) in aqueous two-phase systems (ATPS) by bioaffinity were studied. The synthesis of affinity polymers to recover this enzyme was also studied. Initially the extraction of f3-galactosidase from Kluyveromyces Iactis, from Kluyveromyces fragi/is, from Aspergillus oryzae and from Escherichia co/i was compared. It was observed that only the f3-galactosidase from Escherichia colí partitioned to the top phase in. a system formed of 15% PEG 4000 and 13.6% phosphate (partition coefficient, K = 52). f3-galactosidases from other sources partition into the bottom salt-rich phase, together with the main contaminant proteins, preventing separation and purification. The specific ligand APGP (p-aminophenyl 1-thio-f3-D-galactopyranoside) is an inhibitor of f3-galactosidase, and it was attached to polyethylene glycol (pEG). Two methods of activation were used: activation with tresyl chloride and with tionyl chloride. The yield for activation of tresyl chloride was 74%, determined by elementary sulphur analysis, and the yield for activation with tionyl chloride was 86%. A new two-step method for extraction and purification of the enzyme f3-galactosidase from Kluyveromyces fragilís was then developed. In the first step, an affinity system composed of 6% PEG 4000-APGP and 8% dextran 505 was used, where f3-galactosidase primarily partitioned toward the top phase (K 2,330). In the second step, a system formed of 13% PEG-APGP and 9% phosphate salt was used to revert the value of the partition coefficient, K, of f3-galactosidase to 2 x 10-5, thereby achieving the purification and recovery of39% of the enzyme in the bottom salt-rich phase. The extraction of the model protein lysozyme from chicken egg white was studied by affinity in systems with the complex PEG-IDA-CU2+. This enzyme has a histidine residue available on its surface, making possible its recovery in this system. Metal affinity partitioning in ATPS is a useful tool to extract the proteins which have accessible histidine, cysteine or tryptophan on their surfaces. Partitioning of lysozyme in a PEG 4000/phosphate system, pH 7.0, was studied in the presence and in the absence of PEG-IDA-CU2+. The composition of systems without ligands was 13% PEG 4000 + 9% phosphate, and the affinity systems had correspondent amounts of PEG 4000 replaced by 1%, 5% and 10% of PEG-IDA-CU2+. The partition coefficient, K, of the lysozyme increased ninefold when 5% PEG-IDA-CU2+ was used, and 45% of the enzyme was recovered in the top ligand-rich phase of the system. This is a pioneer work on liquid-liquid extraction of lysozyme in ATPS with PEG-IDA-CU2+. Then the extraction of peroxidase from a crude extract of defatted soybean peroxidase (Glycine max) by metal affinity in an ATPS was studied. A two-step liquid liquid extraction process using metalligand was developed aiming to purify the peroxidase. In the first purification step, the system was composed of 14% PEG 4000-IDA-CU2+ and 8% Na2S04and the peroxidase partitioned mainly to the top phase (K = 24). In the second step, a system formed of 14% PEG 4000 and 10% phosphate was used to revert the value of the partition coefficient of peroxidase to the bottom salt-rich phase (K = 0.05), providing the purification and recovery of 64% of the enzyme. The top PEG 4000-IDA-CU2+ -rich phase was washed by ultrafiltration in order to remove the sulphate salt and reused in another cycle of peroxidase purification. Only two steps were enough to recover the enzymes f3-galactosidase and peroxidase in the ATPS by bioaffinity / Doutorado / Doutor em Tecnologia de Alimentos

The actinomycetes are gram-positive bacteria that produce more than two-thirds of the known biologically active microbial natural products, including many commercially important antibiotics, anti-cancer agents, other pharmacologically useful agents, animal health products and agrochemicals. The prevailing utilization of antibiotics continues to be the mainstay against microbial infections and a majority ofthe over six thousand antibiotics discovered thus far are from Streptomyces spp. One of the most well-characterized antibiotic biosynthetic pathway is the one involving the biosynthesis of the penicillins, cephalosporins and cephamycins. This pathway involves two initial steps which are common in filamentous fungi, lower eukaryotes and prokaryotes. The penam nucleus of penicillins and the cephem nucleus of both cephamycins andcephalosporins are formed by the condensation of the three precursor amino acids L-a-aminoadipic acid, Lcysteine and L-valine by a mechanism designated as 'non-ribosomal peptide synthesis', which involves activation and condensation of the three component amino acids and epimerization of the L- to D-valine to form a linear acyclic tripeptide called o-(L-a-aminoadipyl)-L-cysteinyl-Dvaline (ACV) by the action of a peptide synthetase. ACV is then cyclized to form isopenicillin N, an intermediate that contains an L-a-aminoadipyl side-chain attached to the penem nucleus (Fig. 1.2) by isopenicilin N synthase (IPNS or Cyclase) and this encompasses the creation of the Beta-lactam and thiazolidine rings. A broad range of ~-lactam producing Streptomyces spp were grown, the DNA extraction procedure optimised and total chromosomal DNA isolated. A bioinformatics analysis of known IPNS gene sequences allowed the synthesis of PCR primers for the iso-penicillin N synthase gene. IPNS genes and lPNS-like genes were successfully amplified from the total DNA of ten strains including two novel thermophilic strains, A. and B. Sequencing was carried out on the genes from S. hygroscopicus, S. tanashiensis and the two thermophiles A and B. This allowed development of the conditions for gene shuffiing of the IPNS gene which was carried out pairwise and resulted in the reconstitution of shuffied genes of the correct size. The resulting mixed gene sequences were cloned into the pTrcHis2-TOPO expression vector and the plasmid DNA screened and assayed for IPNS activity using HPLC which showed ten fold increase in IPNS activity as a result of the shuffiing.

Chronic inflammation in response to Aß peptide deposits is a pathological hallmark of Alzheimer's disease (AD). The inflammatory environment includes populations of reactive and proliferating microglia and astrocytes and perturbed vasculature. However, the association between activated glial cells and cerebrovascular dysfunction remain largely unknown. This study has used Aß1-42 intrahippocampal injection as an animal model of inflamed AD brain to characterize mechanisms of glial-vasculature responses as a basis for chronic inflammation. Preliminary findings suggested Aß1-42-injected brain demonstrated vascular remodeling including evidence for formation of new blood vessels (angiogenesis). This result led to study of the effects of the anti-angiogenic/anti-inflammatory compound, thalidomide on activated glial cells and perturbations in the vasculature in an Aß1-42 peptide-injected rat model. First, Aß1-42 injection was found to cause perturbations in vasculature including new blood vessel formation and increased BBB leakiness. Second, thalidomide decreased the vascular perturbations and the glial reactivity and conferred neuroprotection. Overall, these results suggest that altered cerebral vasculature is integral to the overall inflammatory response induced by peptide. Experiments then examined the level of parenchymal plasma proteins in brain tissue from AD and nondemented (ND) individuals. AD, but not ND, brain tissue demonstrated high levels of fibrinogen immunoreactivity (ir). Aß1_42 injection into the rat hippocampus increased the level of parenchymal fibrinogen, which was reduced by treatment with the defibrinogenating agent, ancrod. In addition, ancrod also attenuated microglial activation and prevented neuronal injury. Overall, these results demonstrate that extravasation of blood protein and a leaky BBB are important in promoting and amplifying inflammatory responses and causing neuronal damage in inflamed AD brain. Microglial chemotactic responses to VEGF (vascular endothelial growth factor) receptor Flt-1 were next studied. Treatment with a monoclonal antibody to Flt-1 (anti-Flt-1 Ab) in the peptide-injected hippocampus diminished microglial reactivity and provided neuroprotection. Secondly, anti-Flt-1 Ab inhibited the AI3142-induced migration of human microglia. These results suggest critical functional roles for Flt-1 in mediating microglial chemotaxis and inflammatory responses in AD brain. The overall conclusion from my work is that AP deposits induce microglial reactivity which subsequently causes vascular remodeling resulting in an amplified inflammatory microenvironment which is damaging to bystander neurons. / Medicine, Faculty of / Anesthesiology, Pharmacology and Therapeutics, Department of / Graduate

A semicircular focussing spectrometer has been built to examine beta spectra in the energy range below 100 Kev. The detection of the beta particles is accomplished by means of Geiger counters filled with the saturated vapor of liquid heptane (C₇H₁₆) kept in a bath of melting ice. The windows of the counters are made from thin films of zapon about 5 to 8 micrograms/cm² in thickness. The sources are mounted on similar films approximately 10 micrograms/cm² and have an average total thickness of the order of 30 micrograms/cm² . The combination of thin source and thin windows enables measurements of spectra to be made down to an energy of 2 Kev. An examination of the beta spectrum of RaD (₈₂Pb²¹⁰) with the spectrometer has been carried out. It consists of L, M and N conversion lines of a 47 Kev. gamma ray, a peak at about 3 Kev assigned to conversion of a 7.7 Kev gamma in the M shell of the atom, and a primary beta spectrum. A Kurie plot of the primary beta spectrum yields an end point of 21.7 Kev. In addition there are two weak conversion lines at 18 and 21 Kev which are tentatively assigned to the L conversion of gamma rays of 34 and 37 Kev. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

PART 1 A new method has been used to suppress the undesirable Compton electrons ordinarily present in photoelectron spectra. As much as 90% of the Compton electron intensity was removed. This was accomplished by electronic cancellation of the individual Compton electrons. The method has been used with a thin lens type of spectrometer and has made possible the detection of new gamma rays at .391, .857 and 1.00 Mev. in Ra(B + C), at 1.01 Mev. in Ta¹⁸², and at .472 and .843 Mev. In Sb¹²⁴. No.new gamma rays were observed from Co⁶⁰. PART 2 A search for double beta decay in Sn¹²⁴ has been made using a coincidence technique particularly suited to double beta decay under the Majorana form of neutrino theory. Negative results were obtained and a lower limit of 0.3 - 0.7 x 10¹⁷ years has been set on the half-life of the process. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

An intermediate image beta ray spectrometer has been constructed using the two magnets from two thin lens spectrometers, previously in use in this laboratory. A surface barrier type detector replaces the scintillator -photomultiplier arrangement used before, resulting in greatly reduced background noise. The performance of this spectrometer is considerably better than the two it replaces, having resolutions of 0.51 %, 0.7 %, 0.94 % and 2.2 % at transmissions of 0.49 %, 0.96 %, 1.26 % and 5.96 %. The normal energy range is from 25 Kev, to 1.5 Mev but it can be extended to 2.0 Mev with some loss of transmission. An examination of the beta spectrum of Eu¹⁵⁴ was carried out with this instrument. A Kurie plot of the continuum has been made and six primary beta groups found with end point energies of 1.866 Mev, 1.198 Mev , 0.976 Mev , 0.843 Mev , 0.579 Mev , and 0.274 Mev with relative abundances of 10.8 %. 0.67 %, 4.6 %, 17.0 %, 37.8 %, and 29.1 %. Both end-points and relative intensities are in excellent agreement with data from other workers. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The objctive of this thesis was AN assessment of the value of the Orco Property Group Company. It required making out a strategic analysis, financial analysis and working out a financial plan. For the actual valuing I decided to choose the DCF Equity method.

Tesis presentada a la Universidad de Chile para optar al grado de Magíster en Bioquímica área de Especialización en Toxicología y Diagnóstico Molecular / En los Errores Innatos del Metabolismo (EIM), los cultivos de fibroblastos (FB) a partir de biopsia de piel, han sido desarrollados con el objetivo de obtener material para la determinación enzimas deficientes en este tipo de patologías y establecer un diagnóstico definitivo. Este tipo de diagnóstico es realizado en laboratorios especializados, debido a la complejidad en el manejo y mantención de los cultivos de FB. El envío de muestras de FB a estos centros debe ser realizado en condiciones que garanticen la viabilidad de las células durante el trayecto, con el objetivo de evitar un retraso en el diagnóstico, lo que podría ocasionar daño neurológico irreversible o la muerte de estos pacientes. Entre los EIM, el grupo de Enfermedades de Depósito Lisosomal (EDL) han sido ampliamente diagnosticadas mediante análisis enzimático sobre muestras de FB. La detección de enzimas lisosomales deficientes en muestras de FB permite confirmar el diagnóstico en este tipo de patologías. El uso de gotas de sangre seca (GSS) en papel filtro ha permitido el desarrollo de Programas de Pesquisa Neonatal para diversos EIM, ya que se ha demostrado ampliamente la estabilidad de metabolitos y enzimas en GSS en papel filtro. Además, la toma de muestra, el transporte y almacenamiento de muestras en este tipo de soporte se ven facilitados. El objetivo de este estudio fue evaluar la estabilidad de la actividad específica de betagalactosidasa, enzima lisosomal deficiente en la Gangliosidosis GM1, un tipo de EDL, en muestras de lisados de FB obtenidos a partir de la línea celular 3T3-L1 y dispuestos en papel filtro. Las muestras fueron sometidas a distintas condiciones de tiempo y temperatura de almacenaje para la evaluación de la actividad enzimática. Las muestras mantenidas a 4°C mostraron estabilidad de la actividad enzimática de betagalactosidasa hasta al menos los 28 días de almacenaje. Las muestras re-almacenadas a 4°C y - 70°C presentaron una mayor estabilidad de la actividad de beta-galactosidasa, en comparación con otras temperaturas de re-almacenaje estudiadas / In Inborn Errors of Metabolism (IEM), fibroblasts (FB) cultures from skin biopsy have been developed in order to obtain material for the determination of deficient enzymes in this type of pathologies and to establish a definitive diagnosis. This type of diagnosis is performed in specialized laboratories, due to the complexity of sample handling and FB culture maintenance. Shipment of FB samples to these centers must be carried out under conditions that guarantee the viability of the cells during the journey, in order to avoid a delay in diagnosis, which may cause irreversible neurological damage or death of these patients. Among the IEM, the Lysosomal Storage Diseases (LSD) group, has been widely diagnosed by enzymatic analysis of FB samples. The detection of deficient lysosomal enzymes in FB samples allows us to confirm the diagnosis in this type of pathology. The use of dried blood spots (DBS) on filter paper has allowed the development of Neonatal Screening Programs for various IEM, because the stability of metabolites and enzymes in DBS on filter paper has been widely demonstrated. Furthermore, sample collection, transport and storage of samples in this type of support are facilitated. The aim of this study was to evaluate the stability of the beta-galactosidase, a lysosomal enzyme that is deficient in GM1 gangliosidosis, a type of EDL, in fibroblasts lysates obtained from the 3T3- L1 cell line and collected on filter paper. Samples were studied under different conditions of time and temperature of storage for the enzymatic activity assessment. Samples kept at 4°C maintained the stability of enzyme activity for at least 28 days of storage. Samples stored at 4°C and -70°C showed increased stability when are re-stored in these temperatures.

Tesis para optar al grado académico de Magister en Bioquímica, área de especialización en Bioquímica Toxicológica y Diagnóstico Molecular y Memoria para optar al título profesional de Bioquímica / En la actualidad la mujer ha decido posponer la maternidad hasta después de los 30 años. El aplazar la maternidad hacia la ventana de subfertilidad (31 a 41 años), provoca una disminución de la fertilidad y en el éxito de los programas de fertilización in vitro, los cuales poseen estrechos márgenes de éxito, que se hacen cada vez más pequeños conforme va aumentando la edad de las mujeres. Por esta razón es necesario conocer los mecanismos involucrados en el envejecimiento ovárico, durante el periodo de subfertilidad femenino. Para ello se ha utilizado el modelo múrido, debido a su similitud con procesos que regulan la función del ovario en el ser humano, considerándose como un buen modelo para comprender los mecanismos involucrados en el envejecimiento reproductivo. Se ha demostrado que durante el periodo de sub-fertilidad y en mujeres menopáusicas, los ovarios presentan características fisiológicas similares a las encontradas en el Síndrome de ovario poliquístico, patología de alta prevalencia en mujeres durante edad fértil. Estas observaciones se basan en el hecho de que en ambas condiciones existe un retraso en el desarrollo folicular, disminución del número de folículos antrales y la aparición de estructuras quísticas, que prevalecen incluso después de la menopausia. Se ha descrito que uno de los factores que participa en la aparición de estas condiciones es el aumento del tono nervioso simpático y del contenido de noradrenalina (NA) intraovárica, la que ejerce su función a través de la activación de los receptores 2-adrenérgicos. Este aumento en la actividad nerviosa simpática del ovario se ha relacionado con un aumento en la secreción de hormonas esteroidales y la mantención y/o aparición de las estructuras quísticas, lo que conduce a problemas de fertilidad. Para disminuir la estimulación del sistema nervioso simpático sobre el ovario en el periodo de subfertilidad de la rata (8 a 10 meses), y para determinar si la NA participa en el cese de la función ovárica y/o formación de los quistes foliculares, se propuso bloquear la acción de los receptores -adrenérgicos. Para ello, se administró una inyección diaria de propranolol (antagonista -adrenérgico), durante 2 meses a ratas que se encuentran en el periodo de subfertilidad. Después de los dos meses de tratamiento se analizó la ciclicidad estral de la rata por medio de la observación microscópica del frotis vaginal, se determinaron las hormonas esteroidales en plasma mediante EIA, la concentración de NA y su metabolito MHPG en ovario mediante HPLC; además se realizó análisis morfológico de los ovarios. Los resultados muestran que el bloqueo -adrenérgico con propranolol permite reactivar el desarrollo folicular. Esto evidenciado por: a) el aumento en el número de folículos antrales sanos y cuerpos lúteos, b) el aumento del porcentaje de ovulación y los niveles de hormonas esteroidales en el plasma, c) la disminución en el número de folículos quísticos (quistes y prequistes) y el tamaño de los folículos tipo III y prequistes. Considerando que durante el envejecimiento existe un aumento del tono adrenérgico sobre el ovario, que podría resultar perjudicial, hemos logrado, mediante el bloqueo - adrenérgico, mejorar la funcionalidad ovárica. Este tratamiento reactivó el desarrollo folicular, evidenciado en la recuperación de la esteroidogénesis y foliculogénesis, dando a este fármaco expectativas para su uso a nivel clínico como terapia de ayuda, para poder expandir o retrasar la ventana de subfertilidad en la mujer / Today women have decided to postpone childbearing even after their thirties. The delay of the motherhood towards the subfertility period is associated to diminished fertility and a decreased success rate in in vitro fertilization programs, the latter being rarely successful and even less successful as women get older. For this reason it became necessary to understand the mechanisms related to ovarian ageing during the subfertility period. To accomplish this, the murine model has been used, because it describes almost all the process that regulates the ovarian function in humans, therefore is a good model for understanding the mechanisms involved in the reproductive aging. It has been show that during the sub-fertility and the menopausal period in woman, the ovaries present physiological characteristics similar to those found in the polycystic ovarian syndrome, the pathology with the highest prevalence in women during the fertility age. The observations are based, for example, in the delay in follicular development, decreased number of antral follicles and the spontaneous generation of cystic structures, that prevail until the menopausal age. Today we know one of the factors that participates in the generation of this condition is the rise in the sympathetic tone and the noradrenaline (NA) released in the ovary, which exerts his function through the 2-adrenergic receptor activation. That is correlated with the steroid hormone secretion and the maintenance or generation of the cystic structures, leading to fertility issues. To inhibit the effect in the rise of the sympathetic tone in the ovary during the sub fertility period, and to determine if the NA participates in the cessations of the ovarian function and/or follicular cyst formation and maintenance, we propose a pharmacological block the - adrenergic receptors. To achieve this we administered propranolol, a -adrenergic receptors antagonist, in a daily injection for 2 months, to rats that have reached the sub fertility period (8 and 10 months old). After 2 months of propranolol treatment, estrous cyclicity was analyzed through vaginal smear, steroidal hormones were analyzed in plasma through EIA, the NA content and one of its metabolites was measured in HPLC and finally we performed a morphological analysis of the complete ovary. The results show that the -adrenergic blockade allows reactivation of the follicular development, which is evidenced by an increase in: a) healthy antral follicles and corpora lutea amount, b) ovulation percentage and esteroidal hormones levels in plasma, and c) decreased amount of cystic follicles (cyst and precyst) and in the follicles size (type III follicles and precyst). Therefore we can observe an activation in follicular development that leads to ovulation and inhibits the cyst formation pathway. During aging there is an increase in the ovarian adrenergic tone. After the -adrenergic blockade, we could see the improvement of the ovarian function and follicular development, as evidenced by the rise in the steroidogenesis and folliculogenesis. These findings let us propose propranolol for use in clinical trials as a clinical therapy help, to expand or delay the sub fertility period in the woman