Thesis (MSc)--Stellenbosch University, 2009. / ENGLISH ABSTRACT: Biotechnological applications are useful for adding value to the local medicinal plants and may provide an alternative source of pharmacologically-active compounds thus assisting with the conservation of wild populations. Salvia africana-lutea aromatic herb has long been used in folk medicine by traditional healers in the Western Cape Province (South Africa) for various ailments. As an in vitro conservation strategy, a continuous S. africana-lutea shoot culture was successfully established in solid MS medium containing BA (0.5 mg L-1) and NAA (0.2 mg L-1). The regeneration rate of the S. africana-lutea plants was high which produced approximately 720 plantlets in 20 culture bottles over a four week cycle. The microshoots were rooted in the MS medium without PGRs prior to acclimatisation. A survival rate of 92% was recorded for the greenhouse-acclimatised shoots. / AFRIKAANS OPSOMMING: Biotegnologiese toepassings is nuttig vir waarde toevoeging tot inheemse medisinale plante en kan ‘n alternatiewe bron van farmakologies aktiewe verbindings verskaf wat bydrae tot die bewaring van populasies in die natuur. Die aromatiese krui Salvia. Africana-lutea is reeds vir ‘n lang tydperk in volks medisyne deur tradisionele geneesheers in die Wes Kaap provinsie (Suid Afrika) vir ‘n verskeidenheid kwale gebruik. ‘n Kontinu S. africana-lutea lootkultuur in soliede Murashige en Skoog (1962) (MS) media wat BA (0.5 mg L-1) en NAA (0.2 mg L-1) bevat, is suksesvol as ‘n in vitro konservasie strategie ontwikkel. Die regenerasie tempo van die S. africana-lutea plante was hoog en het ongeveer 720 plante in 20 kultuur bottels tydens ‘n vier week siklus gelewer. Die mikrolote is op plant groei reguleerder vrye MS media gewortel voordat plante geaklimatiseer is. ’n Oorlewingstempo van 92% is vir die glashuis geaklimatiseerde lote waargeneem.

Tesis entregada a la Universidad de Chile en cumplimiento parcial de los requisitos para optar al grado de Magíster en Ciencias Biológicas. / La medida en que los caracteres florales evolucionan bajo selección mediada por polinizadores ha sido ampliamente estudiada en la literatura. Sin embargo, la relación entre selección y efectividad de los polinizadores es un tema poco estudiado. El presente trabajo busca identificar y cuantificar las fuerzas selectivas ejercidas por abejas y colibríes sobre Erythranthe lutea, una planta herbácea altoandina de Chile central. Una de las principales preguntas en este estudio es evaluar si la selección mediada por polinizador sigue el principio del polinizador más eficiente de Stebbins. Para hacerlo, examinamos la selección putativa sobre tres rasgos florales de E. lutea durante dos años consecutivos a través de la función sexual femenina. Para examinar posibles efectos aditivos y no aditivos de los polinizadores, implementamos cuatro tratamientos en un diseño factorial de 2 x 2 usando Picaflores (P) y Abejas (A) como factores principales. De esta forma, probamos la selección mediada por polinizadores en los siguientes tratamientos: P+A+, P+A-, P-A+, P-A-. Nuestros resultados indican que el polinizador más eficiente fue el abejorro exótico Bombus terrestris, una de las especies responsables de la mayor fuerza selectiva impuesta por abejas. En particular, las abejas promueven la reproducción de flores con corolas más grandes en el período 2016. Sin embargo, durante el período 2017 se detectaron efectos no aditivos, lo que indica que el efecto de las abejas estaba supeditado a la presencia de picaflores y viceversa, lo que impide la evaluación de los efectos independientes. Si bien E. lutea parece estar evolucionando según el principio de Stebbins, es necesario demostrar que el fitness ganado después de la especialización de los rasgos florales excede al costo en fitness asociado a la pérdida de otros polinizadores menos eficientes. La observación de que B. terrestris fue el polinizador más eficiente en el ensamble de polinizadores sugiere que los polinizadores introducidos pueden impulsar nuevos y rápidos procesos de adaptación floral. En consecuencia, comprender el impacto evolutivo de los polinizadores exóticos puede ayudar al diseño de políticas de conservación frente al intercambio biótico y a la homogeneización a gran escala. / The extent to which floral characters evolve under pollinator-mediated selection has been extensively studied in the literature. However, the relationship between selection and pollinator effectiveness is a less understood subject. The present study aims to identify and quantify the selective force imposed by bees and hummingbirds upon Erythranthe lutea, a high Andean herbaceous plant from central Chile. A major question in this study is to evaluate whether pollinatormediated selection follows the Stebbins` principle of the most efficient pollinator. In doing so, we examined putative selection upon three flower traits of E. lutea during two consecutive years through the female sex function. To examine potential additive or nonadditive pollinator effects, we set four treatments in a 2 x 2 factorial design using hummingbirds (H) and bees (B) as main factors. In this way, we tested for pollinator mediated selection in the following treatments: H+B+, H+B-, H-B+, H-B-. Our results indicate that the most efficient pollinator was the exotic bumblebee Bombus terrestris, one of the responsible species of the higher selective force imposed by bees. In particular, bees promoted the reproduction of flowers with large-sized corollas in the 2016 period. However, during the 2017 nonadditive effects were detected, indicating that the effect of bees were contingent to the presence of bees and viceversa, which prevented the assessment of independent effects. While E. lutea seems to be evolving under Stebbins’ principle, it is necessary to demonstrate that the gained fitness after floral traits specialization exceeds the fitness cost associated to the loss of other less efficient pollinators. The observation that B. terrestris was the most efficient pollinator in the pollinator assemblage suggests that introduced pollinators can drive new and rapid floral adaptation processes. In consequence, understanding the evolutionary impact of exotic pollinators can help to the design of conservation policies in the face of biotic exchange and broad scale homogenization. / Proyecto FONDECYT 1150112.

La estructura espacial es una variable que influye en una amplia variedad de fenómenos en ecología y evolución. En ecología evolutiva, se ha señalado que la covarianza fenotipo-fitness puede ser sobrestimada si no se controla por efectos de dependencia espacial. Sin embargo, raras veces la estructura espacial de los organismos ha sido explícitamente considerada en estudios de selección natural y a nuestro conocimiento nunca se ha considerado su efecto para la selección mediada por distintos ensambles de polinizadores tomando en cuenta sus respectivas técnicas de forrajeo y el posible impacto sobre los gradientes de selección por separado. Este estudio se focaliza en la relación de la herbácea Erythranthe lutea con dos ensambles de polinizadores (abejas y picaflores) en una población de Chile central, en un intento por indagar de qué manera la estructura espacial de las plantas afecta las estimaciones de selección fenótipica. Se examinó la asociación de cinco rasgos fenotípicos (número de flores de la planta en un radio de 30 cm, largo del tubo floral, distancia antera-estigma, área de corola y guía de néctar), con estimaciones de fitness femenino, considerando la estructura espacial mediante una función de suavizado en un modelo GAMM. Esto permitió comparar la selección multivariada de los rasgos en presencia y ausencia de la variable espacial asi como el efecto directo de la variable espacial sobre el fitness. Los resultados revelaron autocorrelación espacial en las primeras categorías de distancia en los rasgos de cada tratamiento, pero no en el fitness ni en los residuales del modelo, lo que se vio representado por una baja variación de los coeficientes de selección al controlar por la estructura espacial. A pesar de esto, la estructura espacial tuvo un efecto significativo sobre la producción de semillas en el tratamiento control, en presencia de abejas y picaflores. Independiente de la magnitud, estimaciones de selección que no consideren el espacio como una variable que contribuye a la covariación fenotipo-fitness corren el riesgo de sobre o subestimar las fuerzas selectivas actuando sobre el fenotipo floral en las poblaciones de plantas. / The spatial structure is a variable that influences a wide variety of phenomena in ecology and evolution. In evolutionary ecology, it has been pointed out that the phenotype-fitness covariance can be overestimated if it is not controlled by effects of spatial dependence. However, the spatial structure of organisms has rarely been explicitly considered in natural selection studies and to our knowledge the effect of spatial autocorrelation on selection by different pollinator assemblages has never been considered taking into account their respective foraging techniques and the possible impact on the selection gradients separately. This study focuses on the relationship between the herbaceous Erythranthe lutea and two assemblages of pollinators (bees and hummingbirds) in a population of central Chile, in an attempt to investigate how the spatial structure of plants affects estimates of phenotypic selection. We evaluated the association of five phenotypic traits (number of flowers of the plant in a 30 cm radius, floral tube lenght, anther-stigma distance, corolla and nectar guide area), with estimates of female fitness, considering the spatial structure by a smoothing function in a GAMM model. This allowed us to compare the multivariate selection of traits in the presence and absence of the spatial variable as well as the direct effect of the spatial variable on fitness. The results revealed spatial autocorrelation in the first distance categories in the traits of each treatment, but not in the fitness or residuals of the model which was represented by a low variation of the selection coefficients when controlling for the spatial structure. Despite this, spatial structure had a significant effect on seed production in the presence of bees and hummingbirds. Independent of the magnitude, selection estimates that do not consider space as a variable that contributes to phenotype-fitness covariance may over or underestimate the selective forces acting on the floral phenotype in plant populations. / Proyecto FONDECYT 1150112.

Hintergrund In einer retrospektiven Studie in der Augenklinik Würzburg wurde die Ranibizumabtherapie bei Patienten mit altersabhängiger Makuladegeneration (AMD) im klinischen Alltag ausgewertet. Methoden Patientenakten von Patienten mit AMD, die im Jahr 2007 mit der Ranibizumabtherapie begannen, wurden untersucht. Daten wurden bis zum Ende der Behandlung und/oder Nachbeobachtung bis 2009 gesammelt. Der primäre Endpunkt war das Verhältnis der Patienten, die weniger als 15 Buchstaben (bzw. 0,3 logMAR Einheiten) an Visus verloren zwischen Beginn und nach 12 Monaten. Ergebnisse 375 Patienten wurden einbezogen, nur 298 Patienten beendeten die Untersuchung nach einem Jahr. Nach 12 Monaten verloren 72% der Patienten weniger als 15 Buchstaben. Die Sehschärfe verbesserte sich bis 12 Wochen nach der ersten Injektion und verschlechterte sich danach wieder. Patienten mit mehr als 3 Injektionen profitierten mehr als Patienten mit weniger Injektionen. Durchschnittlich wurden 4,25 Injektionen innerhalb eines Jahres gegeben. Der durchschnittliche Rückgang der Netzhautdicke betrug 50 µm. Schlussfolgerung Intravitreale Injektionen von Ranibizumab in der Augenklinik Würzburg führten zu einer Visusverbesserung. Der Visusgewinn konnte nach 3 Monaten nicht gehalten werden. Bessere Reinjektionskriterien, mehr OCT Untersuchungen und besseres Nachsorgemanagement sollten entwickelt werden. / Background Real-life ranibizumab therapy used in patients with wet age related macular degeneration (AMD) was assessed in a retrospective study in Augenklinik Würzburg Methods Medical records of patients with AMD, who started ranibizumab treatment in 2007, were evaluated. Data were collected until the end of treatment and/or monitoring until 2009. The primary end point was the proportion of patients losing fewer than 15 letters (0,3 logMAR units) from baseline visual acuity at 12 months. Results 375 patients were included, only 298 patients finished one-year examination. At 12 months 72% of the patients lost fewer than 15 letters. Visual acuity improved until 12 weeks after first injection and was not maintained afterwards. Patients with more than 3 Injections profited more than patients with less injections. In average, there were 4,25 injections given in one year. The average decrease in retinal thickness was 50µm. Conclusions Intravitreal administration of ranibizumab in Augenklinik Würzburg improved vision acuity. The vision gain was not maintained after 3 months. Criteria for reinjection, more oct examinations and better control management must be developed.

Ultrasonography is widely used in medical diagnosis with the advantages of being low cost, non-invasive and capable of real time imaging. When interpreting ultrasonographic images of mammalian ovaries, the structures of interest are follicles, corpora lutea (CL) and stroma. This thesis presents an approach to perform CL texture analysis, including detection and segmentation, based on the classiers trained by genetic programming (GP). The objective of CL detection is to determine whether there is a CL in the ovarian images, while the goal of segmentation is to localize the CL within the image. Genetic programming (GP) oers a solution through the evolution of computer programs by methods inspired by the mechanisms of natural selection. Herein, we use rotationally invariant local binary patterns (LBP) to encode the local texture features. These are used by the programs which are manipulated by GP to obtain highly t CL classiers. Grayscale standardization was performed on all images in our data set based on the reference grayscale in each image. CL classication programs were evolved by genetic programming and tested on ultrasonographic images of ovaries. On the bovine dataset, our CL detection algorithm is reliable and robust. The detection algorithm correctly determined the presence or absence of a CL in 93.3% of 60 test images. The segmentation algorithm achieved a mean ( standard deviation) sensitivity and specicity of 0.87 (0.14) and 0.91 (0.05), respectively, over the 30 CL images. Our CL segmentation algorithm is an improvement over the only previously published algorithm, since our method is fully automatic and does not require the placement of an initial contour. The success of these algorithms demonstrates that similar algorithms designed for analysis of in vivo human ovaries are likely viable.

Ultrasonography is widely used in medical diagnosis with the advantages of being low cost, non-invasive and capable of real time imaging. When interpreting ultrasonographic images of mammalian ovaries, the structures of interest are follicles, corpora lutea (CL) and stroma. This thesis presents an approach to perform CL texture analysis, including detection and segmentation, based on the classiers trained by genetic programming (GP). The objective of CL detection is to determine whether there is a CL in the ovarian images, while the goal of segmentation is to localize the CL within the image. Genetic programming (GP) oers a solution through the evolution of computer programs by methods inspired by the mechanisms of natural selection. Herein, we use rotationally invariant local binary patterns (LBP) to encode the local texture features. These are used by the programs which are manipulated by GP to obtain highly t CL classiers. Grayscale standardization was performed on all images in our data set based on the reference grayscale in each image. CL classication programs were evolved by genetic programming and tested on ultrasonographic images of ovaries. On the bovine dataset, our CL detection algorithm is reliable and robust. The detection algorithm correctly determined the presence or absence of a CL in 93.3% of 60 test images. The segmentation algorithm achieved a mean ( standard deviation) sensitivity and specicity of 0.87 (0.14) and 0.91 (0.05), respectively, over the 30 CL images. Our CL segmentation algorithm is an improvement over the only previously published algorithm, since our method is fully automatic and does not require the placement of an initial contour. The success of these algorithms demonstrates that similar algorithms designed for analysis of in vivo human ovaries are likely viable.

Thèse (M.Sc.)--Université Laval, 1998. / Bibliogr.: f. 59-64. Publié aussi en version électronique.

Made available in DSpace on 2015-12-06T23:46:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2014 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Objetivos: Comparar os valores de densidade optica de pigmento macular (MPOD) obtidos atraves dos metodos de fotometria de flicker heterocromatico (HFP) e autofluorescencia (AF) em um grupo de pacientes normais; comparar os valores de MPOD em pacientes diabeticos e nao-diabeticos, investigar a relacao entre esses valores e os niveis sericos de hemoglobina glicosilada e perfil lipidico; e, finalmente, investigar a relacao entre a idade e a distribuicao dos valores de MPOD ao redor da fovea em pacientes normais. Metodos: No primeiro estudo, 10 pacientes (20 olhos) normais (sem doencas oculares ou sistemicas) foram incluidos e testados para MPOD atraves dos metodos de HFP e AF. O metodo de AF utiliza dois comprimentos de onda diferentes para a aquisicao das imagens atraves de um oftalmoscopio de varredura a laser confocal modificado (Heidelberg Retina Angiograph, HRA, Heidelberg Engineering, Inc., Heidelberg, Alemanha). Os valores para as duas tecnicas foram obtidos em 4 excentricidades diferentes ao redor do centro da fovea (0,25, 0,5, 1 e 1,75°). Cada olho foi testado tres vezes para cada um dos metodos, e a analise estatistica foi realizada atraves de regressao linear e teste t pareado. Em um segundo estudo, 43 pacientes (43 olhos) diabeticos tipo 2 e normais foram incluidos prospectivamente e alocados em 3 grupos: grupo 1 (controle; n=14), grupo 2 (diabeticos sem sinais de retinopatia; n=17) e grupo 3 (diabeticos com retinopatia nao proliferativa leve; n=12). Todos os pacientes foram submetidos a exame oftalmologico completo e foram coletadas informacoes sistemicas e oculares, incluindo o uso de suplementos vitaminicos contendo carotenoides. A avaliacao da MPOD foi realizada atraves do HRA. Os valores obtidos em 2 excentricidades ao redor do centro da fovea (0,5 e 2°) foram comparados entre os grupos atraves da analise de variancia. Os niveis sericos de hemoglobina glicosilada e lipideos (HDL, LDL, colesterol total e triglicerides) foram correlacionados com os niveis da MPOD para cada grupo atraves de regressao linear. Finalmente, em um terceiro estudo, os valores da MPOD de 30 pacientes (30 olhos) normais foram obtidos atraves do HRA em 3 excentricidades retinianas (0,5, 1 e 2°) e correlacionados com a idade atraves de regressao linear. Resultados: Para a comparacao entre as tecnicas, os valores obtidos pela HFP foram consistente e significativamente inferiores aos valores obtidos pelo HRA (p<0,001) em todas as excentricidades retinianas testadas. Houve uma correlacao significativa entre os valores obtidos pelos dois metodos em quase todos os locais testados, sendo que a correlacao mais forte foi observada no ponto mais afastado da fovea (1,75°) (r=0,73). Em relacao a comparacao entre diabeticos e normais, a media dos valores da MPOD obtidos a 2° do centro da fovea variou significativamente para os tres grupos [grupo 1 (0,29 ± 0,07 DU), grupo 2 (0,22 ± 0,09 DU) e grupo 3 (0,14 ± 0,05 DU), p<0,001]. Alem disso, observou-se uma correlacao inversa e significativa entre os niveis de hemoglobina glicosilada e os valores medios da MPOD a 2° para todos os pacientes (r=-0,63, p<0,001). Nao foram encontradas correlacoes significativas com niveis de lipideos sericos, duracao do diabetes ou idade. Os pacientes incluidos para a analise de correlacao com a idade apresentaram 23 a 77 anos (idade media ± DP = 48,6 ± 16,4 anos). Diferencas significativas para os valores medios de MPOD obtidos a 0,5, 1 e 2° do centro da fovea foram encontradas (0,49 ± 0,12 DU; 0,37 ± 0,11 DU; 0,13 ± 0,05 DU, respectivamente, p<0,05). Os valores da MPOD a 0,5 e 1° e a idade mostraram uma correlacao significativa (p&#8804;0,02), ja os valores da MPOD a 2° nao apresentaram correlacao com a idade (p=0,06). Conclusoes: Os valores da MPOD obtidos atraves do HRA mostraram correlacao significativa com os valores obtidos pelo metodo padrao de HPF, porem foram consistentemente mais elevados em todas as excentricidades retinianas testadas. Estes resultados sugerem que o metodo pode ser usado com seguranca em pacientes incapazes de realizar o teste de HPF, o que e essencial para uma aplicacao clinica mais ampla da analise de pigmento macular. Pacientes diabeticos tipo 2 com e sem retinopatia apresentaram niveis reduzidos da MPOD quando comparados aos pacientes nao-diabeticos. Alem disso, observou-se uma correlacao inversa e significativa entre os niveis de hemoglobina glicosilada e esses valores quando todos os pacientes foram analisados. Finalmente, os valores da MPOD obtidos em uma populacao normal foram mais elevados proximo ao centro da fovea. Esses valores apresentaram pico entre 45-50 anos de idade, seguido por uma reducao gradual apos 60 anos de idade / BV UNIFESP: Teses e dissertações

Diabetes mellitus is a chronic disease characterised by prolonged hyperglycaemia,especially postprandial, in association with the consumption of diets that promote obesity. While different types of the disease have been identified, Type II diabetes also known as insulin dependent diabetes is most prevalent. Treatment for patients with this disease is usually a combination of exercise, low caloric diet and specific medical intervention through the use of allopathic medicines or surgery. While the number of treatment option is large, unfortunately, treatment is usually associated with complication such as drug adverse reactions and failure to halt disease progression. As a result new therapies are required. Herbal medicines such as those derived from the Ficus species, which have been used traditionally in the treatment of diabetes, may serve as new source of drug therapies. The aim of this study was to evaluate the effectiveness of selected South African Ficus species for their potential ability to manage Type II diabetes using in vitro and in vivo screening models. Dried and ground leaves of ten Ficus species were extracted separately with acetone, chloroform and hexane for determination of its phytochemical constituents. Since acetone extracted more variety of compounds, the extracts was used for determination of total polyphenol content, antioxidant activity, α-amylase and α-glucosidase inhibitory activity, cytotoxicity, glucose uptake in primary cell cultures and established cell lines, and insulin release in pancreatic cell lines. The most active extract (F. lutea) was subjected to solvent-solvent fractionation and the six fraction subsequently evaluated by the same assays. The most active fraction (ethyl acetate) was hereafter subjected to fractionation for the isolation of bioactive compound(s) or direct evaluation in a mouse obesity model. The acetone extract of F. lutea had the highest polyphenolic content (56.85 ± 1.82 mg GAE/g dry weight), the strongest antioxidant activity (4.80 ± 0.90 TEAC) and the highest α-amylase inhibitory activity with an EC50 value of 9.42 ± 2.01 μg/ml. Although the extract of F. lutea had the highest sucrase (64.31 ± 3.57%) inhibitory activity at concentration of 0.5 mg/ml, the ECβ of F. sycomorus (217 ± 69 μg/ml) was the best followed by F. lutea (289 ± 111μg/ml). Based on the correlation coefficient between polyphenol and alpha amylase inhibition (0.80) and alpha glucosidase (sucrase) inhibition (0.84), and the partial non-competitive manner by which the acetone extract of F. lutea inhibited the α-amylase and α-glucosidase enzymes, the polyphenols appear to be in part responsible for the evident activity. All ten Ficus species were less toxic than doxorubicin (positive control) but contained compounds that are generally relatively more toxic to the Vero kidney cells than to the C3A liver cells. The extract of F. craterostoma was the least toxic to the C3A and Vero cells, while the LCβ for the extract of F. lutea extract were relatively non-toxic to the Vero cells (214.8 ± 5.0 μg/ml) and more toxic (126.0 ± 6.8 μg/ml) to the C3A cell line. In the glucose uptake assays using primary rat abdominal muscle or epididymal fat cells, F. lutea acetone extracts (200 μg/ml) induced greater glucose uptake of 10.8 ± 1.8% for muscle and of 32.0 ± 8.4% for fat respectively, in comparison to the DMSO control wells.A similar response was seen with the established C2C12 muscle and H-4-II-E liver cell lines, where F. lutea in a dose related manner increased glucose uptake and at the highest concentration (500 μg/ml) increase glucose uptake by 14.9 ± 2.3% and 19.3 ± 0.6% respectively. In contrast no result was quantifiable in the established 3T3-L1 pre-adipocytes cell line, most likely due to a flaw in the methodology. The concurrent insulin addition, (1 and 10 μM) also potentiated the glucose utilisation in the F. lutea treated C2C12 and H-4-II-E cells. On addition of extracts to the RIN-m5F pancreatic β-cells, the extract of F. lutea stimulated a dose related increase in insulin release with insulin secretion of 120.8 ± 11.1% at the highest concentration (500 μg/ml) and concurrent dose related decrease in cell viability in comparison to the untreated control. As a result it would appear that F. lutea acetone extracts have a dual mechanism behind its ability to reduce glucose concentrations. The extract of Ficus lutea, was further subjected to solvent-solvent fractionation in hexane, chloroform, dichloromethane, ethyl acetate, n-butanol and water due to its superior response. The ethyl acetate fraction had the highest polyphenolic content (100.5 ± 1.6 mg GEA/g dried extract) and the highest sucrase inhibitory activity (126.8 ±30.6 μg/ml), while the n-butanol fraction had the highest α-amylase inhibitory activity (26.5 ± 1.3 μg/ml). Nonetheless the inhibition of the α-amylase enzyme activity by the various fractions was in all cases lower than that for the crude extract. In the cytotoxic assay using Vero monkey kidney and C3A liver cell line, the hexane fraction was the least toxic while the ethyl acetate fraction was relatively non-toxic, it had the lowest LDβ against the Vero cells (LDβ = 126.9 ± 1.5 μg/ml). In the glucose uptake assays, the ethyl acetate fraction stimulated the greatest glucose uptake into the C2C12 muscle and H-4-II-E liver cells in dose responsive manner, with no added benefits being achieved through the concurrent addition of insulin. The ethyl acetate fraction also enhanced insulin secretion in RIN-m5F pancreatic β-cells, albeit to a lower extent than the crude extract with dose related decrease in cell viability. With the ethyl acetate fraction being the most active fraction with moderately toxicity, further isolation was attempted. Five compounds were isolated, namely lupeol, stigmasterol, α-amyrin acetate, epicatechin and epiafzelechin, with all of the compounds except epiafzelechin previously known to possess antidiabetic activity. The ethyl-acetate fraction was also evaluated for its weight reducing potential in obese mouse model. Unfortunately no in vivo activity was discernible. In conclusion, this study is the first to report on the in vitro antidiabetic activity of the extract of F. lutea.. / Thesis (PhD)--University of Pretoria, 2012. / Paraclinical Sciences / unrestricted

Le trou maculaire (TM) est un défaut dans la rétine au niveau de la zone centrale de la macula (fovéa). Typiquement, les patients atteints de cette pathologie auront une diminution de leur acuité visuelle (AV) et de la métamorphopsie. Le traitement pour ces patients consistera en une vitrectomie par la pars plana (VPP) dans laquelle le vitré est retiré et remplacé par une tamponnade (SF6, C3F8, air ou huile de silicone). Après cette chirurgie, le succès chirurgical, soit de fermeture anatomique du TM, est très élevé. Toutefois, plus récemment, on s'aperçoit que malgré un taux de fermeture anatomique élevé, les résultats visuels après l'intervention chirurgicale ne sont pas aussi importants, d'où la nécessité d'identifier les facteurs pronostiques liés à la VPP dans les TM qui ont fermé chirurgicalement et de tenter de prédire les résultats visuels suivant la VPP. En ce qui concerne les TM qui n'ont pas fermé lors d'une première VPP, il est intéressant d'évaluer les résultats fonctionnels et anatomiques à la suite d'une VPP de reprise. Nos travaux ont démontré que les yeux avec une durée du TM plus courte, une taille du TM plus petite et une AV préopératoire plus élevée ont obtenu de meilleurs résultats visuels après une première chirurgie réussie. Nous avons par la suite produit un modèle hybride basé sur des données cliniques et des tomographies par cohérence optique haute définition (HD-OCT) préopératoires de TM, et ce, à l'aide de l'intelligence artificielle, afin de tenter de mieux prédire les résultats visuels. Les modèles basés sur les données cliniques ou les HD-OCT ont obtenu de bonnes performances discriminantes individuellement. Toutefois, la combinaison des deux modèles dans un modèle hybride n'a pas significativement amélioré les performances. Enfin, les TM qui subissaient une VPP de révision (non-fermeture chirurgicale à la première VPP) montraient une fermeture anatomique dans 85% des cas et avaient une amélioration de l'AV au fil du temps. / Idiopathic full thickness macular hole (MH) is a defect of all layers of the fovea. Typically, patients with this condition will experiment decreased visual acuity (VA) and metamorphopsia. Treatment for these patients will consist in a pars plana vitrectomy in which the vitreous is removed and replaced by a tamponade (SF6, C3F8, air or silicone oil). After this surgery, the surgical success, or anatomical closure of the MH, is very high. However, more recently, it has been noticed that despite a high anatomical closure rate, the visual results after the surgery are not quite as important, hence the need to identify the prognostic factors related to vitrectomy in patients with closed MH and to predict visual results following vitrectomy. For MH that did not close during the primary vitrectomy, it is interesting to assess the functional and anatomical results following a revision vitrectomy. Our works provided that eyes with shorter MH duration, smaller MH size and higher preoperative VA achieved better visual outcomes after successful MH surgery. We then produced a hybrid model based on clinical data and preoperative MH high-definition optical coherence tomography (HD-OCT), using artificial intelligence to try to better predict visual results. Both the clinical data and HD-OCT models had good discriminative performances. Combining both into a hybrid model did not significantly improve performance. Finally, MH that underwent revision vitrectomy (nonsurgical closure at primary vitrectomy) showed anatomical closure in 85% of cases and had VA improvement over the time.