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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
231

Vaccination of BALB/c Mice with an Alhydrogel Adjuvanted Whole Cell Trichomonas vaginalis Formulation

Smith, Jeffrey D. 14 January 2014 (has links)
A human safe, Alhydrogel adjuvanted whole cell Trichomonas vaginalis vaccine was tested for efficacy in a BALB/c mouse model of vaginal infection. Additionally, the systemic and local immune response were measured. Vaccination reduced incidence and increased clearance of infection, and induced both systemic and local humoral immune responses. CD4+ cells were detected in vaginal tissues following intravaginal challenge with T. vaginalis, but were not seen in uninfected mice. CD4+ cells were detected more often, earlier, and in greater numbers in vaccinated vaginal tissues compared to unvaccinated controls. Presence of CD4+ T cells following infection can have significant implications of increasing HIV susceptibility and transmission. These data suggest that the vaccine induces local and systemic immune responses, and confers significantly greater protection against vaginal challenge than unvaccinated vaginal challenge. These data support the potential for a human vaccine against T. vaginalis infection that could also impact the incidence of HIV infections.
232

Regional neurochemical characterization of the flinders sensitive line rat with regard to glutamate-nitric oxide and cGMP signalling pathways / Estella Lily Minnaar.

Minnaar, Estella Lily January 2008 (has links)
The serious nature of MDD has intensified the need to identify and elucidate new neurobiological targets for antidepressant drug action. Depression presents with evidence for degenerative pathology that relates to disturbances in excitatory glutamatergic pathways, particularly the N-methyl-D-aspartate (NMDA) receptormediated release of the pleiotropic molecule, nitric oxide (NO), and cyclic guanosine monophosphate (cGMP). The contribution of the glutamate-NO/cGMP pathway may realize great importance as a fundamental substrate underlying the pathophysiology of major depression. In the next generation of antidepressant drugs, the nitric oxide pathway could playa dynamic role in addressing urgent therapeutic needs. In this study, we have used a genetic model of depression, the Flinders Sensitive Line (FSL) rat, to investigate the surrogate markers of the NO/cGMP pathway. The aim was to determine whether the depressive-like behaviour of the hypercholinergic FSL rat is accompanied by altered activation of the NO/cGMP pathway. To this end, the extent to which the FSL and Flinders Resistant Line (FRL) rats differ neurochemically with regard to basal hippocampal and frontal cortical NOS-activity, as well as nitric oxide (NO) and cGMP accumulation, were determined. Additionally, select behavioural assessments were performed to confirm the anxiogenic phenotype of the FSL strain. For neurochemical determinations a sensitive fluorometric reversed phase highperformance liquid chromatographic (HPLC) assay was developed to analyze total nitrite and nitrate in brain tissue. Nitrate was enzymatically converted to nitrite before derivatization with 2,3-diaminonaphthalene (DAN). The stable and highly fluorescent product, 2,3-naphthotriazole (NAT), was quantified. Secondly, the quantity of the amino acid L-citrulline was measured by HPLC with electrochemical detection after o-phthalaldehyde (OPA) derivatization. L-citrulline formation was used as an index for nNOS activity. Finally, a direct, competitive enzyme immunoassay kit was used to determine the downstream activity of the NO-pathway in brain tissue. FSL rats were compared to FRL rats with respect to sensitivity to serotonin 5-HT1A . receptor-mediated hypothermia under our lab-conditions. The Open Field Test (OFT) behavioural assessment was performed to compare FSL with FRL groups under baseline conditions according to their level of inherent anxiety. The parameters used to measure anxiety were number of line crosses (locomotor activity), time spent in middle blocks and social interaction time between pairs of rats. As an additional behavioural assessment, the Forced Swim Test (FST) was performed to assess behavioural restraint measured as time of immobility. Basal cGMP levels in the frontal cortex were found to be significantly less in FSL than in FRL rats, whereas the levels in the hippocampus did not differ significantly. No other significant differences with respect to NO and nNOS activity were apparent in either of the brain areas. The hypothermia test confirmed a significantly greater decrease in temperature in the FSL rat than the FRL rat. The FST did not confirm any differences in immobility time between the two rat strains. In the OFT, FSL rat groups exhibited behaviour that indicated significantly more anxiety than FRL rats. Under basal conditions, FSL rats do not present with significant changes in markers of the NO cascade in the hippocampus and frontal cortex compared to FRL controls, including NOS activity as well as NO accumUlation. However, cGMP levels were found to be significantly lower in the frontal cortex of FSL rats versus FRL rats, although not in the hippocampus. Since the FSL rat is known to be hypercholinergic, these data support an interaction between the NO/cGMP pathway and the cholinergIc system in the frontal cortex but not hippocampus of FSL animals. The mechanisms and implications of such a mutual involvement need further clarification. Further, this anatomical differentiation may have important implications for understanding the role of NO in the depressive-like behaviour of the FSL rat and, indeed, may reveal more on the neurobiology and treatment of depression. Through the performed behavioural assessments, the FSL and FRL rats were successfully separated with respect to their anxiety phenotype as well as their heightened response to serotonergic challenge, thus confirming a contribution of both the serotonergic and cholinergic systems to the depressogenic nature of these animals. As concluding remark can be said that under normal basal conditions markers of the NO/cGMP signalling cascade are not altered in FSL vs FRL rats, although cGMP levels are reduced in the frontal cortex of FSL rats, supportive of an NO-independent mechanism of cGMP regulation, possibly involving ACh. / Thesis (M.Sc. (Pharmacology)--North-West University, Potchefstroom Campus, 2009.
233

Cardiotoxicity from cancer therapy : a translational approach to biomarker development

Cove-Smith, Laura Suzanne January 2015 (has links)
Background: Heart damage from cancer therapy is a significant problem for survivors. Some of the most effective treatments, such as anthracyclines, cause heart toxicity that can lead to significant morbidity and mortality. Cardiotoxicity also contributes to the loss of promising cancer drugs in early development and is notoriously difficult to predict. This translational project employs parallel pre-clinical and clinical studies to explore circulating biomarkers and cardiac magnetic resonance imaging (CMR) during development of anthracycline associated cardiotoxicity with the aim of finding biomarkers to aid clinical decision making and enable forward/back translation. Methods: Pre-clinical work: A rat model of chronic anthracycline-induced cardiomyopathy was developed involving 8 weekly intravenous boluses of doxorubicin followed by a 4 week ‘washout’ period. A time course assessment of cardiac function using multiple MRI parameters was performed alongside a panel of circulating biomarkers measured prior to dosing. Clinical work: In parallel following ethical approval, 30 cancer patients receiving standard anthracycline chemotherapy were recruited. Serial CMR scans were performed using standard and new exploratory techniques before, during and after treatment and blood was taken to evaluate a similar panel of cardiotoxicity biomarkers using multiplex ELISA at corresponding time points. Results: Pre-clinical results: Systolic and diastolic function declined progressively, culminating in left ventricular dysfunction (LVEF < 50%) by 12 weeks. Myocardial electron microscopy revealed myofibrillar and mitochondrial damage after one dose and gross histopathological damage after 5 doses. Myocardial contrast enhancement and troponin I increased significantly after eight doses and preceded LV dysfunction. Extensive fibrosis was seen 1 month after drug cessation. Clinical results: LVEF declined progressively in all patients and 7 patients (23%) had persistent LV dysfunction 12 months after therapy. Troponin I elevations were seen towards the end of therapy and peak troponin I corresponded with LVEF decline. None of the other circulating biomarkers correlated strongly with outcome. Lower baseline extracellular volume (ECV) was associated with greater LVEF decline but little change in ECV was seen over time. Baseline dyssynchrony was associated with worse outcome and deteriorated with time alongside LVEF decline. Conclusions: Results suggest that troponin I and cardiac MRI are sensitive translational tools in drug induced cardiotoxicity. However, troponin I is a relatively late marker, peaking after substantial myocardial damage, too late to halt or change reatment. The imaging suggests that fibrosis and inflammation cannot be detected within a year of chemotherapy but baseline ECV and strain analysis may have a role in risk stratification.
234

Avaliação da eficácia de um antagonista do receptor do peptídeo liberador da gastrina em modelos experimentais de artrite

Oliveira, Patricia Gnieslaw de January 2011 (has links)
O peptídeo liberador da gastrina (GRP) é o homologo mamífero da bombesina (BN). Ambos GRP e seus receptores têm sido encontrados na sinóvia de pacientes com artríte reumatoide. O receptor do peptídeo liberador da gastrina (GRPR) pode ser considerado como um alvo terapêutico para doenças inflamatórias. RC-3095 é um antagonista do receptor de GRP. Este estudo avaliou os efeitos anti-inflamatórios do RC-3095, um antagonista específico do receptor do peptídeo liberador da gastrina, em dois modelos experimentais de artrite: induzida por colágeno do tipo II e induzida por adjuvante (CIA e AIA, respectivamente) e os mecanismos envolvidos. O RC-3095 foi administrado aos camundongos com CIA ou com AIA provocado por albumina bovina metilada (mBSA), diariamente. A incidência e severidade da doença foram avalidos por escore clínico e achados histológicos. A imunohistoquímica para o receptor do peptídeo liberador da gastrina (GRPR) na CIA. Migração de neutrófilos, determinação de glicosaminoglicanos (GAGs) e ensaio de linfoproliferação usando MTT em AIA. As citocinas: IL-17, IL-1 e TNF sobre os joelhos em AIA e CIA foram avaliados usando o ensaio imunoenzimático (ELISA). Analise da população de células T regulatórias por citometria de fluxo em AIA. Os resultados demonstraram que o RC-3095 reduziu a migração de neutrófilos, a hipernocicepção mecânica e a perda de proteoglicanos nos camundongos com AIA. Estes resultados estão associados com a inibição das citocinas pró-inflamatórias (IL-17, IL-1 e TNF-) e os níveis de proliferação de linfócitos e aumento do número de células T reguladoras (Treg). No modelo da CIA, o RC-3095 apresentou uma redução significativa nos escores da artrite e gravidade da doença, determinada histologicamente. A Inflamação sinovial, hiperplasia sinovial, formação de pannus e alterações erosivas foram drasticamente reduzidas nos camundongos artríticos tratados com RC-3095. Além disso, o RC-3095 demonstrou redução significativa no conteúdo das citocinas próinflamatórias, como IL-17, IL-1 e TNF-, e reduziu a expressão de receptores GRP nos animais doentes. Estes achados sugerem que via GRP tem um papel significativo na artrite crônica, e sua inibição pode ser explorado como uma estratégia terapêutica. / Background: The gastrin-releasing peptide (GRP) is the mammalian homolog of bombesin (BN). Both GRP and their receptors have been found in synovium of patients with rheumatoid arthritis. GRPR may be considered as a therapeutic target for inflammatory diseases. RC-3095 is a GRP receptor antagonist. Objective: To evaluate the anti-inflammatory effects of RC-3095 in two experimental models of arthritis, collagen and antigen-induced arthritis (CIA and AIA, respectively) and the mechanism involved. Methods: RC-3095 was administered daily to mice with CIA or with AIA provoked by methylated bovine serum albumin (mBSA). Disease incidence and severity were assessed by a clinical index and histologic features. Immunohistochemistry for GRPR in CIA. Migration of neutrophils, determination of glycosaminoglycans (GAG's) and Lymphoproliferation assay using MTT in AIA. The cytokines: IL-17, IL-1β, TNF on his knees in AIA and CIA were evaluated using enzyme-linked immunosorbent assay (ELISA). Analysis of regulatory T cells by flow cytometry in AIA. Results: The RC-3095 reduced neutrophil migration, mechanical hypernociception and the proteoglycan loss in mice with AIA. These findings are associated with the inhibition of proinflammatory cytokines (IL-17, IL-1β and TNF-α) levels and lymphocyte proliferation and increase of T regulatory cell number. In the CIA model, RC-3095 exhibited significant reduction in arthritic scores and the severity of disease determined histologically. Synovial inflammation, synovial hyperplasia, pannus formation and extensive erosive changes were all dramatically reduced in the arthritic mice treated with RC-3095. Furthermore, the mice treated with RC-3095 showed significant reduction in contents of proinflammatory cytokines, such as IL-17, IL-1β and TNF-α. Conclusion: Moreover RC-3095 diminished the GRP receptor expression in arthritic mice. These findings suggest that GRP pathway has a significant role in chronic arthritis, and its inhibition can be explored as a therapeutic strategy.
235

Etude de l’effet de l’hyperthermie sélective induite par laser diode 1210 nm sur les cicatrices chéloïdes : étude expérimentale et clinique / Assessment of 1210 nm laser-diode system for keloid treatment : experimental and clinical studies

Philandrianos, Cécile 04 July 2012 (has links)
IntroductionLes cicatrices chéloïdes (CC) sont des pathologies de la cicatrisation cutanée entraînant des gênes fonctionnelles et esthétiques souvent invalidantes. Elles sont liées à un excès de fabrication et une désorganisation du collagène lié en parti à un dérèglement du TGFβ. Les lasers thermiques permettent d'améliorer la cicatrisation par le biais d'une modification de la réponse inflammatoire. En effet, une élévation de la température entre 45 et 53°C entraine une hyperexpression des HSP 70, responsables d’une modification de l’expression du TGFβ. Le laser diode 810nm a déjà prouvé son efficacité mais il est contre indiqué chez les sujets de phototypes foncés qui sont les plus à risque de développer des CC. L'objectif de ce travail était d'évaluer l'effet d’un laser thermique sur les cicatrices chéloïdes chez l’animal et dans le cadre d’une étude clinique.Détermination des paramètres su laserDes études sur des explants de peau, puis sur des sujets volontaires sains ont permis de montrer que la longueur d’onde 1210 nm était la plus adaptée dans cette indication car elle est peu absorbée par la mélanine. Le choix des paramètres du laser ont également été déterminés afin d’obtenir une élévation contrôlée de la température cutanée. En théorie, un tir de laser diode 1210 nm, 5.1W/cm² pendant 10 secondes permet d’élever la température jusqu’à 53°C.Mise au point d’un modèle animal de CCIl n’existe pas de modèle animal de CC permettant d’étudier l’effet d’un laser. Nous avons donc mis au point un modèle pour le besoin de l’étude. Des fragments de CC humaines comprenant le derme et l’épiderme ont été greffés chez 40 souris nudes. Une évaluation clinique et histologique a permis de confirmer la bonne intégration du greffon et la persistance de son caractère chéloïde pendant 4 mois.Etude du laser diode 1210nm chez un modèle animal de CCUne étude du laser 1210 nm a été réalisée sur notre modèle animal. Il a été réalisé des tirs de laser directement sur les greffons et des évaluations cliniques et histologiques ont permis de montrer l’absence d’effet indésirable. La mesure de la température cutanée au moment du tir de laser était de 45°C en moyenne.Etude du laser diode 1210nm après excision intra chéloïdienne : étude cliniqueParallèlement à l’étude animale, il a été réalisé une étude pilote visant à évaluer la faisabilité et la sécurité d’un protocole de traitement des cicatrices chéloïdes utilisant le laser diode 1210nm. Il était réalisé une excision intra cicatricielle, puis la suture était irradiée par le laser 1210nm pendant environs 10 secondes. 20 patients ont été inclus dans l’étude. L’objectif de suivi était de 2 ans, mais l’étude est toujours en cours. Jusqu’à présent, il n’a été noté aucun effet délétère du laser. 8 patients ont bénéficié d’injections de corticoïdes en raison de récidive de la chéloïde à 6 mois.ConclusionCe travail à permis de mettre au point un modèle animal original de cicatrice chéloïde permettant pour la première fois l’étude des lasers in vivo. L’utilisation du laser 1210nm, 5.1W/cm2, pendant 10 secondes à entrainé une élévation de la température cutanée jusqu’à 45°C en moyenne sans aucun effet délétère sur la CC chez la souris. L’utilisation du laser thermique diode 1210 nm après une résection intra chéloïdienne n’a montré aucun signe de toxicité chez l’homme. La température cutanée était de 48°C en moyenne à la fin du tir. Une étude à plus grande échelle reste encore à réaliser afin de démontrer une efficacité de ce traitement prometteur. / Introduction Keloid scars (KS) are pathologies of skin healing causing often functional and aesthetic disturbances. They are linked to excess production and disorganization of collagen mostly due to TGF bêta; overproduction. The thermal lasers can improve healing through a modification of the inflammatory response. Indeed, a rise of temperature between 45 and 53 ° C leads to an overexpression of HSP 70, which causes a change in the expression of TGF bêta;. The 810nm laser diode has already proven to be effective but its wavelength cannot used on dark phototypes who are prone to developing KS.The objective of this study was to evaluate the effect of a thermal laser on keloids in animal and in the context of a clinical study.Determination of laser parameters Studies on skin explants, and on healthy volunteers have shown that 1210 nm was the most suitable wavelength for this indication because it is poorly absorbed by melanin. The laser parameters were also carefully determined in order to control the skin temperature elevation. For a 1210 nm laser diode, an irradiance of 5.1W/cm² for 10 seconds leads to a maximum temperature of 53 ° C.Development of a KS animal model. Since, there was no KS animal model of DC , an innovative one was developed for this specific study. Fragments of human KS including the dermis and epidermis were transplanted in 40 nude mice. A clinical and histological evaluation confirmed the successful integration of the graft. At 4 months, it was proven that the KS remained unchanged. Study of the 1210nm diode laser in an KS animal modelThe 1210 nm laser was evaluated on our KS animal model. Laser irradiation was performed on the grafts. Clinical and histological evaluations have shown no adverse reactions. A 45 ° C mean temperature was recorded during laser irradiation .Study of l the 1210nm diode laser after intrakeloid excision. Parallel to the animal study, a pilot study was performed to assess the feasibility and safety of a 1210nm diode laser irradiation. An intrakeloid excision was achieved; the suture was then irradiated for about 10 seconds. 20 patients were included in the study. The study is still ongoing. A 2-year follow up is scheduled. So far, it was noted that no harmful effects of the laser. 8 patients received injections of corticosteroids due to of keloid recurrence at six months.conclusionAn original KS animal model was developed for the first time to study of the in vivo effects of laser irradiation. It was demonstrated that a 1210nm diode laser (5.1W/cm², for 10 seconds) led to a 45°C skin temperature without any deleterious effect. The 1210 nm diode laser after intrakeloid excision showed no signs of toxicity in humans. In humans, the maximum temperature was 48 ° C +/- 3°C . A long term follow-up on a large series of patients is still necessary to confirm the effectiveness of this promising treatment.
236

Cellules dendritiques plasmocytoïdes et infections virales : rôle physiopathologique et potentiel vaccinal / Plasmacytoid dendritic cells and viral infections : physiopathologic role and vaccinal potency

Martinet, Jérémie 11 October 2012 (has links)
La réponse immune lors d'une infection par le VHB est essentielle pour éliminer le virus. Le virus module le système immunitaire pour échapper à son contrôle. Le mécanisme par lequel le virus module l'immunité est encore mal connu. Les cellules dendritiques plasmocytoides (pDC) jouent un rôle crucial dans l'immunité antivirale de part leur capacité à capturer et apprêter les antigènes viraux afin d'induire une réponse immune adaptative. Les pDCs représentent un bon potentiel pour restaurer une immunité anti-VHB fonctionnelle, mais le VHB pourrait moduler les pDCs pour échapper au contrôle immunitaire. Dans une première partie, nous avons évalué le potentiel des pDCs à restaurer l'immunité anti-VHB en contexte d'hépatite B chronique. Nous avons utilisé une lignée de pDCs HLA-A*0201+ chargée avec des peptides HLA-A*0201 restreints dérivés des antigènes HBc et HBs du virus afin d'amplifier des lymphocytes T spécifiques ex vivo à partir de cellules de patients atteints d'hépatite B chronique. Nous avons ensuite établi un modèle de souris humanisées (Hepato-HuPBL) afin d'évaluer le potentiel thérapeutique de la stratégie in vivo. La stimulation de PBMC ou de lymphocytes infiltrant le foie (LIL) issus de patients HLA-A*0201+ par la lignée de pDC chargée avec le peptide HBc a permis d'amplifier des lymphocytes T spécifiques de HBc et fonctionnels dans 45,8% des cas. Le groupe de non répondeurs était caractérisé par la présence d'Ag HBe ou un plus fort niveau de lymphocytes T régulateurs. L'efficacité thérapeutique du vaccin de pDC a été évaluée dans un modèle de souris NOD-SCID β2m-/- reconstituées avec des PBMC issus de patient VHB et xenotransplantées avec des hépatocytes humains transfectés avec le VHB. La vaccination de ces souris avec la lignée de pDC chargée avec les peptides HBc et HBs a permis l'amplification de lymphocytes T CD8 spécifiques du VHB capables de lyser spécifiquement les hépatocytes infectés in vivo. Ainsi, la lignée de pDC chargée avec des peptides dérivés du VHB est capable d'amplifier des lymphocytes T CD8 spécifiques du VHB et fonctionnels in vitro et in vivo. Cette nouvelle stratégie d'immunothérapie pourrait donc restaurer une immunité antivirale et permettre l'élimination du virus chez les patients atteints d'hépatite B chronique. Dans une deuxième partie, nous avons évalué le rôle physiopathologique des pDCs au cours de l'infection chronique par le VHB et les conséquences fonctionnelles sur le cross-talk pDC/NK. Des défauts fonctionnels des pDCs et des cellules NK ont été observé chez les patients atteints d'hépatite B chronique. Cependant le cross-talk pDC/NK ainsi que les mécanismes en jeu n'ont pas encore été élucidé. Nous avons étudié le phénotype et la capacité de répondre à une stimulation TLR-L des pDCs de patients comparé aux pDCs de donneurs sains puis nous avons étudié les conséquences sur le cross-talk entre pDCs de patients (virémiques ou avirémiques) et cellules NK hétérologues. Les pDCs de patients montrent un phénotype plus activé que les pDCs de donneurs sains mais ne sont pas capables de répondre à une stimulation TLR9-L. De plus, les pDCs de patients virémiques ne sont pas capables d'activer les fonctions cytotoxiques des cellules NK. Cette perturbation du cross-talk pDC/NK semble liée à un défaut de production d'IFNα et d'expression d'OX40L par les pDCs de patients virémiques, ainsi qu'à la présence d'une quantité importante d'IP-10 dans le plasma des patients. Ainsi, le VHB pourrait échapper à l'immunité en altérant la fonction des pDCs et perturbant le cross-talk pDC/NK par un mécanisme dépendant de IP-10, OX40L et IFNα. / The immune control of HBV infection is essential for viral clearance. The virus is able to modulate the immune system to escape this control. The mechanisms involved remain largely unknown. Plasmacytoid dendritic cells (pDC) play a crucial role in anti‐viral immunity due to their ability to capture and process viral antigens and subsequently induce adaptive immune responses. PDCs are therefore promising to restore functional anti‐HBV immunity, but HBV could modulate the pDCs to escape the immune control. First, we investigated the potential of pDCs in triggering anti‐viral immunity against HBV during chronic infection. We used a HLA‐A*0201+ pDC line loaded with HLA‐A*0201-restricted peptides derived from HBc/HBs antigens to amplify specific T cells ex vivo from chronic HBV patients. Then we established an Hepato-HuPBL humanized mouse model to address the therapeutic potential of the strategy in vivo. Stimulation of PBMC or liver-infiltrated lymphocytes from HLA‐A*0201+ chronic HBV patients by the HBc peptide-loaded pDC line elicited functional HBV-specific CD8 T cells in 45.8% of cases. The “non-responder” group of patients was characterised by the presence of HBe Ag or higher level of regulatory T cells. The therapeutic efficacy of the pDC-based vaccine was evaluated in NOD-SCID β2m-/- mice reconstituted with HBV patients' PBMC and xenotransplanted with human HBV-transfected hepatocytes. Vaccination of these mice with the HBc/HBs peptide‐loaded pDC line elicited HBV-specific T cells in vivo able to specifically lyses infected hepatocytes. Thus pDCs loaded with HBV‐derived peptides can elicit functional virus-specific T cells in vitro and in vivo. This new cell-based immunotherapeutic strategy could restore functional anti‐viral immunity and clear the virus in chronic HBV patients. In the second part, we investigated the pathophysiological role of pDCs from chronic HBV patients and the functional consequences on pDC-NK cross-talk. Functional impairment have been observed in both pDC and NK cells in chronic HBV patients. However, the cross-talk pDC/NK and the mechanisms involved have not been elucidated. We studied the phenotype and the ability to respond to a TLR-L stimulation of the pDCs from HBV patients compared to healthy donors, and we investigated the consequences on the cross-talk between patients' (viremic or aviremic) pDCs and heterologous NK cells. PDCs show higher levels of activation in patients compared to healthy donors but were not able to respond to TLR9-L stimulation. In addition, pDCs from viremic chronic HBV patients failed to trigger a normal NK cytolytic function after TLR9-L stimulation. This pDC-dependant NK dysfunction was related to impaired IFNα secretion and OX40L expression by pDCs from viremic patients, and related to high plasma IP-10 levels found in patients. In conclusion HBV could escape the immune system by impairing pDC function and subsequent pDC/NK cross-talk by a mechanism involving IP10, OX40L and IFNα.
237

Efeitos da estimula??o ambiental sobre os aspectos motores, cognitivos e neuronais em um modelo farmacol?gico progressivo da doen?a de Parkinson

Camp?lo, Clarissa Loureiro das Chagas 11 April 2013 (has links)
Made available in DSpace on 2014-12-17T15:37:15Z (GMT). No. of bitstreams: 1 ClarissaLCC_DISSERT.pdf: 1971406 bytes, checksum: 8e8a69b6fc521e4494ca707dfa5a90fe (MD5) Previous issue date: 2013-04-11 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / A doen?a de Parkinson (DP) ? uma doen?a cr?nica e progressiva que acomete principalmente os neur?nios dopamin?rgicos da subst?ncia negra parte compacta (SNpc) e ? caracterizada pela presen?a de sintomas motores , altera??es cognitivas e depress?o. Estudos com modelos animais da DP permitem ampliar o conhecimento dos mecanismos neuropatol?gicos e bioqu?micos e auxiliar no desenvolvimento de novas abordagens terap?uticas. A estimula??o ambiental ? uma estrat?gia neuroprotetora em diferentes modelos animais de dano neurodegenerativo, inclusive na DP. Os estudos realizados at? o momento priorizam as repercuss?es da estimula??o ambiental sobre os aspectos motores e em modelos farmacol?gicos agudos desta patologia. O presente estudo teve como objetivo avaliar as repercuss?es da exposi??o ao ambiente enriquecido nos aspectos motores, cognitivos e neuronais (n?veis de tirosina hidroxilase (TH) e fator neurotr?fico derivado do enc?falo (BDNF)) no modelo progressivo da DP pela administra??o repetida de reserpina (RES) em camundongos. Foram utilizados 76 camundongos machos tratados repetidamente com ve?culo ou 0,1 mg/kg de RES (s.c), divididos em duas condi??es de alojamento: padr?o e ambiente enriquecido. Nos animais mantidos na condi??o padr?o, o tratamento com RES foi capaz de provocar altera??es motoras (teste de catalepsia, atividade motora no campo aberto e movimentos orais) e altera??es cognitivas nos teste de reconhecimento do objeto novo (RON) e na tarefa da esquiva discriminativa no labirinto. Quando iniciada antecedendo o tratamento (mas n?o quando iniciada concomitantemente), a estimula??o ambiental retardou o aparecimento dos d?ficits motores avaliados pela catalepsia e facilitou a recupera??o destes d?ficits ap?s o final do tratamento. Al?m disso, a estimula??o ambiental preveniu o aparecimento do d?ficit cognitivo no teste de RON. Na avalia??o histoqu?mica, o tratamento com RES reduziu o n?mero de c?lulas positivas para TH na SNpc e em VTA dos animais eutanasiados ao final das inje??es. Contudo, 30 dias ap?s o final do tratamento esse d?ficit foi revertido. Apesar da ANOVA ter apontado efeito do ambiente neste par?metro, essa diferen?a n?o foi detectada pelo teste post hoc. O tratamento com RES reduziu os n?veis de BDNF no estriado e na regi?o CA3 do hipocampo e a exposi??o ao ambiente enriquecido impediu esse efeito no estriado. Desta forma, o protocolo de estimula??o ambiental utilizado no presente estudo, quando iniciado previamente ao tratamento, foi eficiente em retardar o aparecimento dos d?ficits motores e acelerar a recupera??o destes, al?m de prevenir o d?ficit de mem?ria de curto prazo e evitar a redu??o dos n?veis de BDNF. Esses resultados corroboram estudos pr?vios sugerindo que altera??es pl?sticas cerebrais induzidas pelo enriquecimento ambiental promovem efeitos ben?ficos sobre a progress?o de doen?as neurodegenerativas
238

Avaliação da eficácia de um antagonista do receptor do peptídeo liberador da gastrina em modelos experimentais de artrite

Oliveira, Patricia Gnieslaw de January 2011 (has links)
O peptídeo liberador da gastrina (GRP) é o homologo mamífero da bombesina (BN). Ambos GRP e seus receptores têm sido encontrados na sinóvia de pacientes com artríte reumatoide. O receptor do peptídeo liberador da gastrina (GRPR) pode ser considerado como um alvo terapêutico para doenças inflamatórias. RC-3095 é um antagonista do receptor de GRP. Este estudo avaliou os efeitos anti-inflamatórios do RC-3095, um antagonista específico do receptor do peptídeo liberador da gastrina, em dois modelos experimentais de artrite: induzida por colágeno do tipo II e induzida por adjuvante (CIA e AIA, respectivamente) e os mecanismos envolvidos. O RC-3095 foi administrado aos camundongos com CIA ou com AIA provocado por albumina bovina metilada (mBSA), diariamente. A incidência e severidade da doença foram avalidos por escore clínico e achados histológicos. A imunohistoquímica para o receptor do peptídeo liberador da gastrina (GRPR) na CIA. Migração de neutrófilos, determinação de glicosaminoglicanos (GAGs) e ensaio de linfoproliferação usando MTT em AIA. As citocinas: IL-17, IL-1 e TNF sobre os joelhos em AIA e CIA foram avaliados usando o ensaio imunoenzimático (ELISA). Analise da população de células T regulatórias por citometria de fluxo em AIA. Os resultados demonstraram que o RC-3095 reduziu a migração de neutrófilos, a hipernocicepção mecânica e a perda de proteoglicanos nos camundongos com AIA. Estes resultados estão associados com a inibição das citocinas pró-inflamatórias (IL-17, IL-1 e TNF-) e os níveis de proliferação de linfócitos e aumento do número de células T reguladoras (Treg). No modelo da CIA, o RC-3095 apresentou uma redução significativa nos escores da artrite e gravidade da doença, determinada histologicamente. A Inflamação sinovial, hiperplasia sinovial, formação de pannus e alterações erosivas foram drasticamente reduzidas nos camundongos artríticos tratados com RC-3095. Além disso, o RC-3095 demonstrou redução significativa no conteúdo das citocinas próinflamatórias, como IL-17, IL-1 e TNF-, e reduziu a expressão de receptores GRP nos animais doentes. Estes achados sugerem que via GRP tem um papel significativo na artrite crônica, e sua inibição pode ser explorado como uma estratégia terapêutica. / Background: The gastrin-releasing peptide (GRP) is the mammalian homolog of bombesin (BN). Both GRP and their receptors have been found in synovium of patients with rheumatoid arthritis. GRPR may be considered as a therapeutic target for inflammatory diseases. RC-3095 is a GRP receptor antagonist. Objective: To evaluate the anti-inflammatory effects of RC-3095 in two experimental models of arthritis, collagen and antigen-induced arthritis (CIA and AIA, respectively) and the mechanism involved. Methods: RC-3095 was administered daily to mice with CIA or with AIA provoked by methylated bovine serum albumin (mBSA). Disease incidence and severity were assessed by a clinical index and histologic features. Immunohistochemistry for GRPR in CIA. Migration of neutrophils, determination of glycosaminoglycans (GAG's) and Lymphoproliferation assay using MTT in AIA. The cytokines: IL-17, IL-1β, TNF on his knees in AIA and CIA were evaluated using enzyme-linked immunosorbent assay (ELISA). Analysis of regulatory T cells by flow cytometry in AIA. Results: The RC-3095 reduced neutrophil migration, mechanical hypernociception and the proteoglycan loss in mice with AIA. These findings are associated with the inhibition of proinflammatory cytokines (IL-17, IL-1β and TNF-α) levels and lymphocyte proliferation and increase of T regulatory cell number. In the CIA model, RC-3095 exhibited significant reduction in arthritic scores and the severity of disease determined histologically. Synovial inflammation, synovial hyperplasia, pannus formation and extensive erosive changes were all dramatically reduced in the arthritic mice treated with RC-3095. Furthermore, the mice treated with RC-3095 showed significant reduction in contents of proinflammatory cytokines, such as IL-17, IL-1β and TNF-α. Conclusion: Moreover RC-3095 diminished the GRP receptor expression in arthritic mice. These findings suggest that GRP pathway has a significant role in chronic arthritis, and its inhibition can be explored as a therapeutic strategy.
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Recherche de gènes impliqués dans des rétinopathies canines comme modèles de rétinites pigmentaires humaines / Research of genes implicated in canine retinopathies as models of human retinitis pigmentosa

Bunel, Morgane 26 September 2017 (has links)
Le chien présente de nombreuses maladies génétiques dont les rétinopathies auxquelles je me suis intéressée. Historiquement, l’homme a appliqué aux chiens une sélection artificielle extrêmement forte, créant ainsi près de 400 races répondant à des besoins spécifiques. En uniformisant ainsi de nombreux traits phénotypiques et comportementaux, l’homme a sélectionné les allèles recherchés mais a également concentré involontairement des allèles délétères responsables de maladies génétiques. Ces maladies étant pour beaucoup cliniquement et génétiquement similaires aux maladies humaines, le chien constitue alors un modèle de choix pour en rechercher les bases génétiques et développer de nouvelles thérapies pour un bénéfice mutuel pour l’homme et le chien. J’ai travaillé sur l’Atrophie Progressive de la Rétine (APR) dans deux races avec le concours du Dr Gilles Chaudieu et des clubs de race : le border collie et le berger picard. Concernant l’APR du border collie, les analyses réalisées avant mon arrivée avaient identifié un locus de 20Mb sur le chromosome X. J’ai tout d’abord mis à jour les données épidémiologiques et cliniques d’environ 500 chiens et poursuivi la collecte de prélèvements. Une analyse de liaison génétique pangénomique sur 130 chiens m’a permis de confirmer le mode de transmission et le locus. J’ai ensuite conduis plusieurs analyses génétiques (« homozygosity mapping », analyses des génotypes, séquençage de gènes candidats) sans pour autant réduire le locus ni identifier de mutation causale. Dans ce contexte et grâce à l’avènement des nouvelles technologies de séquençage, j’ai choisi de séquencer le génome complet de trois chiens atteints et deux porteurs apparentés. Ce travail m’a permis d’identifier 117variants dont 9 dans le locus d’intérêt, mais aucun dans des régions codantes. Je me suis donc focalisée sur les variants de régions régulatrices pour 13 gènes candidats. De plus, j’ai identifié cinq variants structuraux, encore en cours d’étude. Concernant l’APR du berger picard, nous avons relancé le projet par la collecte de prélèvements et la réalisation d’un pedigree de 154 chiens. Ce travail a amené à une collaboration tripartite internationale par le séquençage de deux chiens atteints et deux indemnes d’APR, dont les analyses sont en cours. Cette thèse m’a permis d’aborder la génétique d’une maladie génétique rare chez l’homme grâce à un modèle spontané original ; et même si ce travail n’a pas abouti à l’identification de mutations à ce jour, ces APR restent de bons modèles génétique et thérapeutique pour les rétinites pigmentaires humaines. / Dogs are affected by numerous genetic diseases including retinopathies, the subject of my thesis. Historically, humans have exerted a very strong artificial selection to dogs, thus creating some 400 breeds to perform specific tasks or to harbour specific traits. By such an homogenisation of phenotypic and behavioural traits, humans have selected desired alleles but also concentrated undesired deleterious alleles responsible of genetic diseases. These diseases are clinically and genetically similar to human genetic diseases, making dogs a model of choice to search for the genetic bases of such genetic diseases and to develop new therapies for a mutual benefit for dogs and humans. I worked on Progressive Retinal Atrophies (PRA) in two breeds, thanks to the contribution of the veterinary ophthalmologist Dr. Gilles Chaudieu and the breed clubs of border collies and berger picard. Concerning the border collie PRA, genetic analyses performed before my thesis allowed the identification of a locus of 20Mb on the X chromosome. I first completed and supplemented the epidemiological and clinical data for about 500 dogs and continued the sample and data collection. A first genetic linkage analysis on 130 dogs allowed to confirm the transmission mode and the locus. I then performed several genetic analyses (« homozigosity mapping », genotypes analyses, candidate gene sequencing) without significantly reducing the locus,neither finding the causal mutation, unfortunately. In this context and thanks to the development of new sequencing technologies, I chose to sequence the entire genome of three PRA affected border collies and two unaffected related dogs. This work allowed the identification of 117variants, 9 in the locus but none in coding regions. I thus focused my research on genetic variants from potential regulatory regions for 13 candidate genes. In addition, I identified five structural variants. The analysis of these variants is still ongoing. Concerning the berger picard PRA, we have re-initiated the project by collecting samples and designing a large pedigree of 154 dogs. This workled to an international collaboration by the sequencing of the entire genomes of 2 affected and 2 unaffected bergers picards for which the statistical analyses are ongoing. This thesis allowed me to work on the genetics of rare diseases in humans with a spontaneous and original animal model and even if thiswork has not yet reached the identification of the mutations, these two PRAs in these two breeds remain good genetic and therapeutic models for human RP RetinitisPigmentosa.
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Avaliação da Terapia Fotodinâmica aplicada com luz intensa pulsada em pele sadia de suínos e diferentes fotossensibilizadores / Evaluation of Photodynamic Therapy using intense pulsed light on porcine healthy skin with different photosensitizers

Michelle Barreto Requena 17 July 2015 (has links)
A Terapia Fotodinâmica (TFD) caracteriza-se por um conjunto de processos físicos, químicos e biológicos que ocorre após a administração de compostos fotossensibilizantes, que ficam retidos preferencialmente nos tecidos alterados, ao que se segue a irradiação com luz visível, ativando esses fotossensibilizadores (FS) por meio da absorção da luz. Nesta modalidade terapêutica, ocorrem mecanismos de transferência de energia entre o FS e o oxigênio molecular presente nos tecidos, gerando espécies reativas de oxigênio capazes de levar as células à morte. A TFD tem uma de suas principais aplicações no tratamento do câncer de pele, e este trabalho tem por objetivo otimizar tal aplicação utilizando a luz intensa pulsada (LIP) como sistema de irradiação. Na literatura, estudos demonstram a eficiência da aplicação de LIP na área dermatológica e estética na remoção de pelos, tratamento de lesões vasculares, acnes e no fotorejuvenescimento da pele, através de efeitos fotoquímicos e térmicos, mas não há relatos sobre aplicações terapêuticas para o câncer de pele. A aplicação da LIP em TFD leva a diferentes tipos de vantagens destacando-se a possibilidade de diminuição do tempo de tratamento, com consequente redução da dor durante o procedimento. Além disso a possibilidade de aplicação de misturas de FSs que absorvam em diferentes comprimentos de onda, promovendo a ativação simultânea de diferentes bandas de absorção que pode levar a potencialização do efeito da TFD. A ideia da irradiação com LIP é permitir a possibilidade de excitar diferentes bandas do FS simultaneamente, bem como reduzir os níveis de saturação do oxigênio dos tecidos devido a longos períodos de irradiação, minimizando também possíveis efeitos térmicos ocasionados pela irradiação prolongada. Neste trabalho, estudou-se a TFD com um equipamento comercial de LIP (Intense Pulse Light, HKS801) utilizando dois precursores do FS endógeno Protoporfirina (PpIX), 5-ácido aminolevulínico (ALA) e aminolevulinato de metila (M-ALA) e os FSs Photodithazine (PDZ) e Indocianina verde (ICV), em modelo de pele normal de suínos. As diferenças relativas à aplicação tópica de ALA e M-ALA por meio de creme e através da aplicação em sistema de injeção de alta pressão sem agulhas (SAFE INJECT) foram avaliadas. O sistema de injeção também foi utilizado para disponibilização dos FSs na pele. O estudo in vitro mostrou que a LIP interagiu com todos os FSs e levou à multiativação de suas bandas. Com relação aos estudos in vivo observou-se diferentes aspectos do uso da LIP para TFD. A avaliação de fluorescência mostrou que a distribuição por injeção foi mais homogênea, sugerindo a possibilidade de protocolos de TFD menos demorados. A análise termográfica mostrou que não ocorre aquecimento relevante do tecido nas aplicações de LIP em aplicações de TFD no protocolo utilizado. A avaliação histológicas das condições entre 24 e 48 horas permitiu observar as diferentes fases do processo cicatricial em função do tempo decorrido. O estudo possibilitou maior entendimento sobre os efeitos da LIP em tecido biológico, especialmente em associação à TFD. Também foi estabelecido, pela primeira vez, um modelo de protocolo para investigação do uso da LIP em modelo animal para TFD em pele, que pode ser extrapolado em futuros estudos para tratamentos oncológicos e dermatológicos. Consideradas as possibilidades oferecidas e a pronta disponibilidade do dispositivo para irradiação, a TFD com LIP torna-se viável técnica e comercialmente para uso clínico. / Photodynamic Therapy (PDT) is mainly composed of physical, chemical, and biological processes that occur after administration of photosensitizing compounds, which are selectively held in abnormal tissues. After visible light irradiation, those photosensitizers (PS) are activated by light absorption. During treatment, energy transfer mechanisms take place between PS and molecular oxygen that is available in tissues, promoting the generation of reactive oxygen species that bring cells to death. One of this technique´s main applications is skin cancer treatment, and this study aims to optimize such a PDT application by using intense pulsed light (IPL) as irradiation system. Literature shows IPL efficacy on dermatological aesthetic procedures, such as hair removal, treatment of vascular lesion, acne and skin photorejuvenation, promoted by photochemical and thermal effects. However, skin cancer treatment was never reported. Using IPL for PDT may bring advantages such as reducing the treatment sessions, which reduces pain during procedures, and the ability to use PS blends that will absorb in different regions of wavelengths, resulting in simultaneous activation of different absorption bands and improving PDT effect. Shorter irradiation may reduce oxygen depletion due to long irradiation periods, and major thermal effects. In this study, PDT was performed using an IPL commercial device (Intense Pulse Light, HKS801) with the application of two PpIX precursors (ALA and MAL) and the exogenous PS Photodithazine (PDZ) and Indocyanine Green (ICG) on porcine health skin model. Administration of the PS or PpIX precursors were investigated both by vehiculation via cream and by high pressure, needle-free injection (SAFE INJECT). The results obtained in this study showed that the damage induced by PDT using the needle-free injection is more expressive than for cream vehiculation. The in vitro study showed that IPL interacted with all PS and promoted absorption bands multi-activation. The in vivo studies showed different aspects of using IPL for PDT. Fluorescence investigation showed that the distribution by the needle-free injection was more homogeneous, suggesting that shorter PDT protocols are possible. Thermography imaging showed that no relevant heating was observed for IPL applications of PDT during the protocols of choice. Histological analysis of conditions between 24 and 48 hours allowed observing the different stages of the healing process as a function of time. This study provided deeper understanding of IPL effects in biological tissues, and particularly when associated to PDT. In addition, for the first time, an investigation protocol for the use of IPL-PDT in porcine healthy skin was designed, which can be extrapolated for future studies on cancer and skin lesions. Given the possibilities and the prompt availability of the irradiation device, IPL-PDT is readily available technically and commercially for clinical use.

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