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The developing chick retina is an extrapituitary site of growth hormone (GH) synthesis and action. GH, GH receptor (GHR) and their mRNAs are present in the neural retina when the neural cells are undergoing proliferation and differentiation during early embryogenesis. It is thus likely that GH acts as an autocrine or paracrine in this location. The present study shows that intra-vitreal injection of a chick GH (cGH) small interfering RNA (siRNA) into the eyes of early embryos [embryonic day (ED) 4] suppresses GH expression in the neural retina and increases the incidence of spontaneous retinal cell death. Our current work also demonstrates a reduction of local IGF-1 expression after retinal GH gene knockdown, suggesting that GH action in retinal cells is regulated through IGF-1 signalling. These results demonstrate that retinal GH is an autocrine/paracrine hormone that acts as a neuroprotective factor in the retina of chick embryos.

Thesis (M.S.)--University of Southern California, 1998. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Southern California, 1998. / Includes bibliographical references.

Previously, we found that 3,4-(methylenedioxy)-1-(2′,3′- epoxypropyl)-benzene (safrole oxide) induced a typical apoptosis in A549 human lung cancer cells by activating caspase-3, -8, and -9. In this study, we further investigated which upstream pathways were activated by safrole oxide during the apoptosis. Immunofluorescence assay combined with laser scanning confocal microscopy revealed that both Fas and Fas ligand (FasL) were up-regulated by the small molecule. In addition, Fas protein distribution was altered, showing a clustering distribution instead of a homogeneous one. Subsequently, Western blot analysis confirmed the up-regulations of Fas and its membrane-binding form of FasL (m-FasL), as well as P53 protein. Conversely, safrole oxide hardly affected integrin β4 subunit expression or distribution, which was reflected from the data obtained by immunofluorescence assay combined with laser scanning confocal microscopy. The results suggested that Fas/FasL pathway might be involved in safrole oxide-induced apoptosis of A549 cells, while integrin β4 might be irrelevant to the apoptosis. Nevertheless, we first found the strong expression of integrin β4 in A549 cells. The study first suggested that safrole oxide might be used as a small molecular promoter of Fas/FasL pathway to elicit apoptosis in A549 cells, which would lay the foundation for us to insight into the new strategies for lung cancer therapy.

no / Recent studies have gained positive results using nanoparticles (NPs) in treating atherosclerosis on animals. But their toxicity and application in treating other heart diseases such as heart failure and endocarditis still need proper investigation. Gold nanoparticles (Au-NPs) were chosen as model substances as they have been successfully used in treating cancer. In this study, we use both H9C2 myoblasts and rat peripheral blood mononuclear cells to determine the influence of Au-NP size on their cytotoxicity and cell apoptosis. H9C2 cells were treated with Au-NPs of a diameter of 5, 20, 40 and 100nmfor 24 hrs before their cell viabilities tested by MTT assay, cell apoptosis measured by flow cytometry, and the generation of reactive oxygen species (ROS) detected by Fluorometric Intracellular ROS Kit. Distribution of the Au-NPs and their effects on the structure of mitochondria and lysosome were detected by electron microscopy. In addition, we obtained rat peripheral blood mononuclear cells and treated them with Au-NPs same with H9C2 cell line. Our results showed NPs of 5, 40, and 100 nm reduced cell viabilities on H9C2 cells while20nm showed no change on cell viability (Ctrl: 100±8.2 vs 20nm: 95.39±9.13, P>0.05, n=6) and some protect effect on ISO induced H9C2 cells apoptosis (ISO: 100±13.5 vs 20nm: 80.19±17.36, P>0.05, n=6). All size of Au-NPs reduced cell viabilities on rat peripheral blood mononuclear cells while 40nm showed the least reduction on cell viability (Ctrl: 100.0±3.0 vs 40nm: 76.31±3.68, P<0.001, n=6) and significant protect effect on ISO-induced rat peripheral monocytes apoptosis (ISO: 100±1.86 vs 40nm: 45.34±10.32, P<0.05, n=6). In addition, 20nm Au-NP showed some protect effect on ROS generation on ISO-induced H9C2 cells (ISO: 100±3.79 vs 20nm: 94.84±4.98, P>0.05, n=6), while 40nm produced more ROS (ISO: 100±3.79 vs 40nm: 141.63±42.81, P>0.05, n=6). Electron microscopy detection showed correlated results in structure. These results on H9C2 cell line are basically in agreeable to our animal study. The protective effect of 20nm may due to its ability to protect ISO-induced ROS generation. The results on rat peripheral monocytes are slightly different to those on H9C2 cells. Further investigation need to focus on the role of NPs size on cell apoptosis by detecting autophagy specific protein through western blotting. / Abstract of conference paper.

In this project I sought to analyse the effects of different free fatty acids (FFAs) on INS-1E β-cells. The saturated fatty acid palmitate is considered toxic whereas the monounsaturated fatty acid oleate is harmless. In my working hypothesis I assumed an additional protective effect of oleate when used in combination with palmitate. Furthermore I aimed to explore in detail the possible causes and signalling pathways responsible for apoptosis or sustained cell survival. I examined the Endoplasmic Reticulum (ER) stress response, called unfolded protein response (UPR), as one essential criterion deciding about cell death or life. Analysis of viability and apoptosis confirmed the deleterious effect of palmitate on INS-1E β-cells after 24h of incubation. Oleate proved not to be harmful and even reversed the toxicity of palmitate. When the main components of the UPR were assessed using Western blot analyses and quantitative PCR was performed I found positive proof that palmitate activated the UPR and ultimately led to apoptosis. By contrast, oleate completely prevented UPR signalling. I conclude that oleate rescues INS-1E β-cells by inhibiting ER stress and its signalling.

Diss. (sammanfattning) Stockholm : Karol. inst., 2007. / Härtill 3 uppsatser.

La stérilisation des espèces aquacoles est recherchée en aquaculture pour remédier aux problèmes de reproduction intempestive et risques de pollution génétique de la reproduction des poissons d'élevage échappés avec des espèces endémiques. Nous avons cherché à caractériser certains des mécanismes mis en jeu lors d'une stérilisation induite par de fortes températures chez une espèce de poissons thermosensible d'intérêt majeur en aquaculture, le tilapia du Nil, Oreochromis niloticus. L'effet d'une température élevée de 37°C sur le développement gonadique a été étudié pendant la différenciation sexuelle chez des alevins et pendant la maturation sexuelle chez des juvéniles, provenant de descendances mixtes (XXXY) et monosexes femelles (XX) /mâles (XY). L'analyse immunohistochimique de la protéine vasa montre que des traitements à 37°C provoquent une diminution du nombre de cellules germinales (CG) qui résulte d'une augmentation du taux d'apoptose et/ou d'une réduction du taux de prolifération de ces cellules, aboutissant à une stérilité partielle et transitoire ou complète et permanente. L'expression du gène vasa, marqueur des CG, est inhibée dans les gonades des poissons traités à 37°C pendant un minimum de 60 jours ; ceci est corrélé avec la réduction du nombre de CG dans ces gonades. La baisse du niveau d'expression des gènes cyp19a1a et amh, respectivement marqueurs de cellules somatiques femelles et mâles, suggère que la température de 37°C affecte également le nombre ou la fonctionnalité des cellules de la granulosa chez les femelles et de Sertoli chez les mâles. Un traitement de 60 jours est nécessaire pour induire de tels effets et semble impacter préférentiellement les gonades femelles. Ce travail confirme que les fortes températures induisent une réduction du nombre de CGs, en modifiant la balance entre les taux d'apoptose et de prolifération cellulaire, conduisant à des stérilités partielles ou totales. / The sterilization of farmed fishes is searched in aquaculture to remedy in the problems of inconvenient reproduction and risk of genetic pollution of reproduction of escaped farmed fishes into the natural environment with endemic species. We characterized some of the mechanisms involved during induced-sterilization by high temperatures in the Nile tilapia, Oreochromis niloticus, a thermosensitive species of major interest in fish farming. The effect of 37°C-elevated temperature on gonadal development was studied during sexual differentiation in fry and during sexual maturation in juvenile, from mix-sexed (XX/XY), all-genetic female (XX) and male (XY) progenies. The immunochemistry analysis of vasa protein shows that 37°C-treatment causes germ cell (CGs) decrease, resulting from an increase of apoptosis rate and/or reduction of cell proliferation, leading to partial and transitory or complete and permanent sterilization.This work confirms that high temperatures induce a decrease of germ cell number, modifying the balance between rates of cell apoptosis and cell proliferation, leading to partial or complete sterilization.The expression profile of vasa gene, marker of germ cells, is inhibited in gonads of fish treated at least during 60 days at 37°C ; that is correlated with the reduction of germ cell number. The reduction of expression levels of cyp19a1a and amh genes, respectively markers of female and male somatic cells, suggests that the 37°C-temperature also affects the number or function of granulosa cells in females and Sertoli cells in males. A treatment of 60 days is necessary to induce such effects and seems to impact preferentially female gonads.