Thesis (M. Med. Sc.)--University of Hong Kong, 2006.

Proefschrift Maastricht. / Met lit. opg. - Met samenvatting in het Nederlands.

Trabajo de Investigación Requisito para optar al Título de Cirujano Dentista / Introducción La periodontitis apical asintomática (PAa) corresponde a un cuadro inflamatorio crónico, producido por infecciones intrarradiculares que se desarrolla en el periápice de los dientes, provocando la destrucción del ligamento periodontal y hueso alveolar. VEGF participa en angiogénesis, aumento de la permeabilidad vascular y vasodilatación, fenómenos centrales en la patogenia de las lesiones periapicales (LPAs) durante la PAa. El objetivo de este estudio fue determinar niveles de VEGF en LPAs consecutivas a necrosis pulpar y controles de ligamento periodontal de piezas sanas. Materiales y Métodos Se incluyeron sujetos con diagnóstico clínico de PAa e indicación de exodoncia (n=20) y sujetos sanos con indicación de exodoncia por ortodoncia (n=20). Las muestras de lesiones apicales y ligamento periodontal extraídas fueron homogeneizadas. Se determinó la concentración de proteínas totales (CPT) en los homogeneizados tisulares mediante el método del ácido bisciconítico. Los niveles de VEGF se determinaron usando un kit comercial “FlowCytomix”. Los datos fueron analizados mediante el software Stata v.11.1 utilizando test chi cuadrado, test t no pareado, test Mann-Whitney y correlación de Pearson. Se consideró estadísticamente significativo un p<0,05. Resultados Se detectó la presencia de VEGF en el 60% de las lesiones y solo en el 20% de los controles (p=0,013). Se encontraron niveles de VEGF significativamente mayores en LPAs en relación con los controles. De modo similar, la CPT fue significativamente mayor en LPAs que en los controles sanos; mientras que los niveles de VEGF estandarizados por CPT no presentaron diferencias estadísticamente significativas. Conclusiones VEGF aumenta en LPAs en relación con controles de ligamento periodontal sano y por tanto podría tener un papel importante en el desarrollo y perpetuación de la PAa. Por su parte, la CPT varía entre tejidos sanos y enfermos aumentando significativamente en los últimos, por lo tanto podría no representar un método adecuado de estandarización.

La endometriosis es una patología caracterizada por la presencia de tejido endometrial fuera de la cavidad uterina que afecta alrededor del 10% de la población femenina en edad reproductiva, pero su etiología y patogénesis aún son poco claras. La presencia aumentada de citoquinas proinflamatorias como el factor de necrosis tumoral alfa (TNF-á) en el fluido peritoneal puede potenciar la capacidad invasiva de este tejido endometrial ectópico mediante la alteración del sistema de las metaloproteinasas (MMPs). Tanto el endometrio ectópico como el endometrio eutópico de estas pacientes son diferentes al de mujeres sin endometriosis. Sin embargo, poco se sabe del comportamiento de las MMPs y menos de su regulación en el endometrio eutópico de estas pacientes. Proponemos que en el endometrio eutópico de pacientes con endometriosis ya existe una expresión alterada del sistema de las MMPs que afecta su funcionalidad y favorece la capacidad invasiva del tejido endometrial, donde TNF-á es una de las citoquinas involucrada en su regulación. Los objetivos del presente trabajo fueron estudiar la expresión de MMP-2, MMP-9, MMP-7, MMP-26, TIMP-2, TIMP-3 y TIMP-4 y el efecto de TNF-á en tejido endometrial eutópico de mujeres con endometriosis y compararlo con endometrio normal (control) en modelos ex vivo a través del ciclo menstrual y en cultivos celulares endometriales. Los resultados en el endometrio de pacientes con endometriosis, respecto al endometrio control, muestran un aumento de MMP-7 en fase proliferativa (mRNA: 56% y proteína: 57%) y una disminución de MMP-9 en fase secretora media (proteína: 58%), de MMP-26 en fase secretora inicial (mRNA: 60%), de TIMP-2 en fases proliferativa (mRNA: 45% y proteína: 50%) y secretora inicial (mRNA: 64%) y de TIMP-4 en fase secretora tardía (mRNA: 98%); MMP-2 y TIMP-3 fueron similares al control. En cultivos celulares de ambos grupos de endometrios: TNF-á (10 ng/mL, 24 horas) aumentó la secreción de MMP-2 (parcialmente inhibido por Bay 11-7085, inhibidor de la vía de NFêB), el mRNA y la secreción de MMP-9 (independiente de NFκB) y el mRNA de MMP-7 (independiente de NFκB) y disminuyó el mRNA y proteína de TIMP-4 (efectos inhibidos por Bay). En endometrio eutópico de pacientes con endometriosis, la expresión o secreción de las MMPs está aumentada y la de los TIMPs reducida, efectos incrementados por TNF-á, lo que puede estar afectando su funcionalidad y promoviendo su actividad proteolítica permitiendo una capacidad mayor para invadir sitios ectópicos

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Envenenamentos por serpentes sÃo um importante problema de saÃde muito difundido em paÃses tropicais. Entre as espÃcies mais perigosas da AmÃrica do Sul encontra-se o gÃnero Bothrops. Acidentes ofÃdicos causados por espÃcies Bothrops podem desenvolver rapidamente dano tecidual local grave, incluindo edema, hemorragia, mionecrose, ulceraÃÃo de pele e dor. A soroterapia tradicional tem eficÃcia limitada contra esses efeitos. Compostos naturais isolados de plantas, principalmente a partir de espÃcies usadas na medicina popular para tratar envenenamentos de serpente, podem ser uma boa alternativa para encontrar novos compostos para melhorar o tratamento do envenenamento e minimizar as sequelas das vÃtimas. Atividade antiofÃdica dos novos alcalÃides esteroidais: 1 -22,23-epoxi-solanida-1,4,9-trien-3-ona (1), 2-22,23-epoxi-solanida-1,4-dien-3-ona (2) 3-3,9-dihidroxi-22,23-epoxi-9-10-secosolanida-1,3,5(10)-trieno (3) isolados das folhas de Solanum campaniforme foram testados atravÃs da inibiÃÃo da atividade fosfolipÃsica, atividade proteolÃtica, miotoxicidade, hemorragia e necrose induzidas pelo veneno de Bothrops pauloensis. Os trÃs compostos foram capazes de inibir completamente a liberaÃÃo de creatina quinase de mÃsculos estriados esquelÃticos e minimizar as alteraÃÃes histolÃgicas sem inibir a atividade fosfolipÃsica A2 do veneno total de B. pauloensis. A inibiÃÃo da miotoxicidade parece ser independente da atividade catalÃtica de fosfolipase (PLA2) e pode estar relacionada à inibiÃÃo da PLA2 Lys 49, enzimaticamente inativas, e / ou uma aÃÃo indireta sobre metaloproteinases. Houve tambÃm, a inibiÃÃo da atividade proteolitica do veneno em diferentes substratos com os trÃs alcaloides A hemorragia, bem como a necrose de pele, ambas induzidas por metaloproteases presentes no veneno, foram reduzidas na presenÃa dos alcalÃides 1 e 2, mas nÃo com o alcalÃide 3. A inibiÃÃo das atividades proteolÃticas e a reduÃÃo dos efeitos hemorrÃgicos e necrosantes induzidas pelo vBp, principalmente atribuÃdos aos alcalÃides 1 e 2, podem estar associadas com a interaÃÃo destes compostos com as metaloproteases presentes no veneno e/ou com Ãons metÃlicos bivalentes necessÃrios para sua aÃÃo. / Snake envenoming is an important health problem widespread in tropical countries. Among the most dangerous species in South America is the Bothrops genus. Snakebites accidents caused by Bothrops species quickly develop severe local tissue damage, including swelling, hemorrhage, myonecrosis, skin ulceration and pain. The traditional serum therapy has limited effectiveness against these effects. Natural compounds isolated from plants, mainly from species used in folk medicine to treat snakebite, are a good choice to find new lead compounds to improve the snakebite treatment and minimize the sequelae of the victims. Antiophidic activity of the new steroidal alkaloids: 22-epoxy-solanide-1,4,9-trien-3-one (1), 22-epoxy-solanide-1,4-dien-3-one (2) and 3,9-dihydroxy-22,23-epoxy-9,10-secosolanida-1,3,5(10)-triene (3) isolated from leaves of Solanum campaniforme was tested through inhibition of phospholipasic activity, proteolytic activity, myotoxicity, hemorrhage and necrosis induced by Bothrops pauloensis venom. The three compounds were able to complete inhibit the creatine kinase release from skeletal muscles and minimize the histological changes, without inhibiting the phospholipasic A2 activity of whole venom. The inhibition of myotoxicity appears to be independent of catalytic activity of phospholipase A2 (PLA2) and may be related to inhibition of PLA2 Lys 49, enzymatically inactive, and / or an indirect action on metalloproteinases. There was also, the inhibition of proteolytic activity of the venom on different substrates with three alkaloids. Hemorrhage as well as skin necrosis, both induced by metalloproteases present in the venom, were reduced in the presence of alkaloids 1 and 2 , but not with the alkaloid 3. Inhibition of proteolytic activities and the reduction of hemorrhagic and necrotizing effects induced by vBp, mainly attributed to the alkaloids 1 and 2, may be associated with the interaction of these compounds with the metalloproteases present in the venom and / or divalent metal ions required for their action.

This study provides a parallel characterization of the cytokine and chemokine response to stroke in the human and mouse brain at different stages of infarct resolution. The study goal was to address the hypothesis that chronic inflammation may contribute to stroke-related dementia. We used C57BL/6 and BALB/c mice to control for strain related differences in the mouse immune response. Our data indicate that in both mouse strains, and humans, there is increased granulocyte macrophage colony-stimulating factor (GM-CSF), interleukin-6 (IL-6), interleukin-12 p70 (IL-12p70), interferon gamma-induced protein-10 (IP-10), keratinocyte chemoattractant/interleukin-8 (KC/IL-8), monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein-1 alpha (MIP-1 alpha), macrophage inflammatory protein-1 beta (MIP-1 beta), regulated on activation, normal T cell expressed and secreted (RANTES), and Tumor necrosis factor-alpha (TNF-alpha) in the infarct core during the acute time period. Nevertheless, correlation and two-way ANOVA analyses reveal that despite this substantial overlap between species, there are still significant differences, particularly in the regulation of granulocyte colony-stimulating factor (G-CSF), which is increased in mice but not in humans. In the weeks after stroke, during the stage of liquefactive necrosis, there is significant resolution of the inflammatory response to stroke within the infarct. However, CD68+ macrophages remain present, and levels of IL-6 and MCP-1 remain chronically elevated in infarcts from both mice and humans. Furthermore, there is a chronic T cell response within the infarct in both species. This response is differentially polarized towards a T helper 1 (Th1) response in C57BL/6 mice, and a T helper 2 (Th2) response in BALB/c mice, suggesting that the chronic inflammatory response to stroke may follow a different trajectory in different patients. To control for the fact that the average age of the patients used in this study was 80 years, they were of both sexes, and many had suffered from multiple strokes, we also present findings that reveal how the chronic inflammatory response to stroke is impacted by age, sex, and multiple strokes in mice. Our data indicate that the chronic cytokine and chemokine response to stroke is not substantially altered in 18-month old compared to 3-month old C57BL/6 mice, although T cell infiltration is attenuated. We found a significant correlation in the chronic cytokine response to stroke in males and females. However, the chronic cytokine response to stroke was mildly exacerbated by a recurrent stroke in both C57BL/6 and BALB/c mice.

Myocardial ischemia and ischemia/reperfusion activate several protein kinase pathways. Protein kinase activation potentially regulates the onset of myocardial cell injury and the reduction of this injury by ischemic and pharmacologic preconditioning. The primary protein kinase pathways that are potentially activated by myocardial ischemia/reperfusion include: the MAP kinases, ERK 1/2, JNK 1/2, p38 MAPKα/β; the cell survival kinase, Akt; and the sodium-hydrogen exchanger (NHE) kinase, p90RSK. The literature does not support a role for ischemia/reperfusion in the activation of the tyrosine kinases, Src and Lck, or the translocation and activation of PKC. This review will detail the role of these protein kinases in the onset of myocardial cell death by necrosis and apoptosis and the reduction of this injury by preconditioning.

Proper regulation of apoptosis during pneumococcal pneumonia is essential for resolution of infection. We hypothesized that reactive oxygen species (ROS) produced during infection causes sufficient DNA damage to alter expression of pro-apoptotic proteins. Despite inducing DNA damage, challenge with pneumococci did not cause alterations the expression of the pro-apoptotic protein Puma (p53 up-modulated regulator of apoptosis) at early (4 and 6 hour) and late (16 and 24 hour) time points tested in this study. Puma-dependent global expression patterns were assessed, and the data demonstrated significant changes in expression of various genes (Prdx2, Ripk1, Api5 and IL-10) involved in cell death and the inflammatory response. In conclusion, although the presence of Puma is necessary for normal apoptotic cellular death and host resolution of infection, Puma expression in bone marrow neutrophils and lung epithelial cells is not dependent on ROS produced during pneumococcal infection.

No description available.

MicroRNA-221 (miR-221) führt in Prostatakarzinomzellen zu einer Induktion einer TRAIL-supprotiven Signatur als Folge einer Interferonaktivierung mit Heraufregulation von STAT-1 und den TRAIL-relevanten, interferonsensitiven Genen TNFSF-10 und XAF-1. Ferner führt die Inhibierung des bekannten Zielgenes SOCS-3 sowie die Inhibierung des neu beschriebenen Zielgenens PIK3R1 zu einer TRAIL-Sensitivierung in den untersuchten Prostatakarzinomzellen. / MicroRNA-221 (miR-221) mediates TRAIL-sensitivation of prostate cancer cells via inducing an TRAIL-supportive signature. This was shown by upregulation of STAT-1 and the TRAIL inducing the interferone sensitive genes XAF-1 and TNFSF-10. Furthermore the inhibition of two miR-221 targets mediates TRAIL sensitivation. The inhibition of the known target SOCS-3 and the new target PIK3R1 both led to TRAIL sensitivation of prostate cancer cells.