No description available.

Au cours de ma thèse, j’ai travaillé sur deux sujets complémentaires. Le premier a concerné l’étude des interactions entre les cellules tumorales et leur microenvironnement, dans quatre modèles de mésothéliomes malins (MM) de rat. Les analyses histologiques du stroma, associées à des analyses protéomiques et de l’expression de différentes cytokines/chimiokines ont permis d’identifier trois stades d’invasivité croissante, associés à des modifications quantitatives de nombreuses protéines et à un infiltrat immunitaire décroissant. La tumeur la plus invasive a été caractérisée par une immunosuppression avec un profil moléculaire spécifique augmentant le potentiel métastatique. Le second sujet a concerné l’évaluation de l’efficacité de la virothérapie anti-tumorale, basée sur l’utilisation de la souche vaccinale du virus de la rougeole MV et de son variant MV-ΔC, pour le traitement du MM. Les deux virus ont induit des régressions tumorales chez des souris NOD SCID transplantées avec deux lignées de MM humains, le MV-ΔC amplifiant cet effet en induisant une mort cellulaire plus rapide, attestée par une réduction plus marquée de la masse tumorale. Ce potentiel apoptotique est associé, in vitro, à une production accrue du signal de danger HMGB1 et à la synthèse d’une grande quantité d’ARN double brin viral. Ces cellules infectées par le MV-ΔC sont aussi capables de favoriser la maturation des cellules dendritiques grâce à la réplication virale et à l’activation de Protéine Kinase R. Ce travail de caractérisation de nouveaux modèles immunocompétents et de nouvelles stratégies thérapeutiques permet d'envisager un meilleur traitement des patients souffrant de mésothéliome. / As a PhD student, I worked in parallel on two complementary subjects. The first one concerned the study of the interactions between tumor cells and their microenvironment in four models of rat malignant mesothelioma (MM), differing in both their immune infiltrate and their metastatic potential. Histological analyses of stroma, together with proteomic analyses and expression of different cytokines, chemokines and growth factors, led us to the identification of three stages of increasing invasiveness, associated with quantitative changes in many proteins and a decreased immune infiltrate. The most invasive tumor was characterized by immunosuppression with a specific molecular profile increasing the metastatic potential. The second topic was the evaluation of the efficacy of anti-tumor virotherapy, based on the use of the Schwarz strain of measles virus (MV) and its variant MV-ΔC for the treatment of MM. Both viruses induced tumor regressions in NOD SCID mice transplanted with two human MM cell lines, but MV-ΔC amplified this effect by inducing faster cell death, as revealed by a marked reduction of the tumor mass. This apoptotic potential is associated, in vitro, with an increased production of the danger signal HMGB1 and the synthesis of a large amount of viral double-stranded RNA. These MV-ΔC-infected cells are also capable of promoting the maturation of dendritic cells through viral replication and activation of the Protein Kinase R. This characterization of new immunocompetent models and novel promising therapeutic strategies may lead to better clinical management of patients with mesothelioma.

No description available.

Glyoxylase II (Glo II, E.C. 3.1.2.6) catalyzes the hydrolysis of S-D-Lactoylglutathione (SLG) to D-Lactate and glutathione. This is the rate limiting step in the conversion of methylglyoxal to D-Lactate. The purpose of the present study was to determine whether or not a relationship exists between some naturally occuring metabolites and in vivo modulation of Glo II. We have observed a non-competitive inhibition (~ 45%) of Glo II in crude preparation of rat liver by GTP (0.3 mM). A factor (apparently protein),devoid of Glo II,when reconstituted with the purified Glo II, enhanced Glo II activity. This coordinate activation and inhibition of Glo II suggest a mechanism whereby SLG levels can be modulated in vivo.

Thesis (M.S.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / There are two types of extracellular fluid in the cochlea: the endolymph of the scala media and the perilymph of the scala vestibuli and scala tympani. Cochlear endolymph and perilymph have different compositions, and the concentration gradient of solutes across the cochlear partition is actively maintained in vivo. In experiments involving fresh cochleas that have been dissected to allow access to the cochlear partition, the cochlea is generally placed in a single medium that aims to nourish the cochlear cells. However, the dissection usually disrupts the separation of endolymph and perilymph across the organ of Corti, the organ in the cochlear partition that contains the auditory sensory cells. Separating the fluids across the cochlear partition during experiments involving dissected cochleas would allow for more physiologically relevant observations to be made. This work was aimed at creating a two-chambered device for holding excised Mongolian gerbil (Meriones unguiculatus) cochlear preparations during in vitro electrical stimulation experiments. Primarily, this device creates experimental conditions that more closely mimic the in vivo physiologic conditions found within the gerbil cochlea by isolating the endolymph medium and perilymph medium bathing the opposing surfaces of the organ of Corti. The device also provides a means to electrically stimulate the organ of Corti and allows for imaging of the response to stimulation. The ability of the device to seal endolymph medium from perilymph medium is shown via electrical resistance measurements between the chambers. The imaging of hair cell motion during electrical stimulation is also demonstrated. / 2031-01-02

The organic or methylated form of mercury (Hg), consisting of one methyl group bound to each atom of Hg, (methylmercury; MeHg), accounts for most of the Hg to which humans are exposed. MeHg, by virtue of its lipophilicity is highly neurotoxic to both the developing and mature central nervous system (CNS). Historically, MeHg has been implicated in high morbidity and mortality rates over the last 40 years in Japan, Iraq, Pakistan and Guatemala. The most common symptom exhibited in these exposure episodes was cerebellar ataxia. Recent in vitro studies using cultured granule cells showed that MeHg alters intracellular calcium ion ([Ca2+]i) homeostasis, potentiates reactive oxygen species (ROS) generation and loss of mitochondrial membrane potential leading to apoptotic death of cerebellar granule neurons. To better understand the neurotoxic mechanisms of MeHg on cerebellum, changes with respect to biochemical processes in cerebellar granule cells and associated behavior changes were investigated. The aims of this dissertation were: (1) to assess mercury concentrations in mouse brain using different routes of administration and different tissue preparations, (2) to determine the behavior effects of in vivo MeHg exposure in young adult mice. (3) to understand specific biochemical processes leading to granule cell death/dysfunction due to in vivo MeHg toxicity in mice, and (4) to determine the toxic effects of in vivo MeHg exposure on mice aged between 16-20 months. The present results showed that repeated oral exposure to MeHg results in greater accumulation of Hg in brain tissue when compared to single oral or subcutaneous exposures at the same concentration of MeHg. Behavior analysis revealed that MeHg at the concentrations used in this study had profound effects on motor coordination and balance in young adult and aged mice. Investigation of biochemical processes in cerebellar granule cells of mice exposed to MeHg showed an increase in ROS generation, alteration of ([Ca2+]i (in young adult mice) and loss of MMP in young adult and aged mice. However, these changes did not lead to apoptotic cell death of granule cells at the concentrations of MeHg used and at the specific time point it was investigated in young adult mice.

University, Diss., 2003--München.

University, Diss., 2003--Heidelberg.

No description available.

Dissertação (mestrado)—Universidade de Brasília, Departamento de Biologia Celular, 2013. / Submitted by Tania Milca Carvalho Malheiros (tania@bce.unb.br) on 2013-04-18T13:55:46Z No. of bitstreams: 1 2013_MarianaMagalhãesNóbrega_Parcial.pdf: 4669193 bytes, checksum: 470b6e88d4408bfc14b01984e61c33ac (MD5) / Approved for entry into archive by Jaqueline Ferreira de Souza(jaquefs.braz@gmail.com) on 2013-04-24T13:51:03Z (GMT) No. of bitstreams: 1 2013_MarianaMagalhãesNóbrega_Parcial.pdf: 4669193 bytes, checksum: 470b6e88d4408bfc14b01984e61c33ac (MD5) / Made available in DSpace on 2013-04-24T13:51:03Z (GMT). No. of bitstreams: 1 2013_MarianaMagalhãesNóbrega_Parcial.pdf: 4669193 bytes, checksum: 470b6e88d4408bfc14b01984e61c33ac (MD5) / A prospecção de peptídeos com atividade biológica é importante do ponto de vista biotecnológico assim como ponto de partida em diversos ramos da pesquisa como no desenvolvimento de novas drogas e na produção de plantas geneticamente modificadas. Este trabalho tem como objetivo a predição e a síntese de peptídeos que tenha atividade antinociceptiva e hipotensora. A predição da estrutura primária dos peptídeos foi realizada com base em trabalhos anteriores do grupo, os quais focam na prospecção e caracterização de peptídeos bioativos, assim como no conhecimento disponível na literatura acerca das propriedades biológicas apresentadas por domínios protéicos específicos. Os peptídeos foram sintetizados por meio de síntese química em fase sólida, utilizando a estratégia Fmoc, seguida da purificação em cromatografia líquida de alta eficiência. O grau de pureza e a confirmação da estrutura primária dos peptídeos sintetizados foram determinados por espectrometria de massa, Maldi e ESI. Os peptídeos foram testados em camundongos , por via intraperitoneal com intuito de avaliar sua possível atividade antinociceptiva, realizaram-se então os testes da placa quente ou Hot Plate e teste de retirada da cauda ou Tail Flick. Os testes in vivo demonstraram que os peptídeos sintéticos PSLEM 11011 e 11012 apresentaram atividade antinociceptiva via receptores opióides com perfil de atividade mais tardio e duradouro em relação a morfina. Eles apresentaram atividade nos dois modelos de testes propostos, podem ter atravessado a barreira hematoencefálica e possuem ação prolongada. ______________________________________________________________________________ ABSTRACT / To prospect of peptides with biological activity is important from the point of view of biotechnology as a starting point in many fields of research as the development of new drugs and the production of genetically modified plants. This study aims to predict and synthesize peptides that have antinociceptive and hypotensive activities. The prediction of the primary structure of the peptides was based on previous work of the group, which focuses on the prospection and characterization of bioactive peptidesas well as in the knowledge available in the literature about the biological properties of specific protein domains. The peptides were synthesized by solid-phase chemical synthesis using Fmoc strategy followed by purification on high performance liquid chromatography. The purity and confirmation of the primary structure of the synthesized peptides were determined by mass spectrometry, MALDI and ESI.The peptides were injected in mice intraperitoneally in order to assess its possible antinociceptive activity through Hot Plate and Tail Flick assays.The in vivo tests showed that synthetic peptides PSLEM 11011 and 11012 have antinociceptive activity via opioid receptors with delayed response and longer activity compared to morphine. The peptides showed activity in both test models proposed in this work, may have crossed the blood-brain barrier and presenting high bioavailability.