Dissertation (Ph.D.).--University of Texas Graduate School of Biomedical Sciences at San Antonio, 2006. / Vita. Includes bibliographical references.

(Zugl.: Ulm, Universiẗat, Diss. : 1992).

Orientador: Enilson Antonio Sallum / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-16T14:54:07Z (GMT). No. of bitstreams: 1 Diniz_ClaudiaKellydeOliveira_M.pdf: 2319655 bytes, checksum: 50260486802400f51cdb98b6fd32a3c0 (MD5) Previous issue date: 2010 / Resumo: O objetivo do presente estudo foi avaliar a influência do diabetes mellitus (DM) sobre a reabsorção óssea alveolar ocorrida no trauma oclusal (TO) na presença e ausência da periodontite experimental (PE) em ratos. Para tanto, 32 ratos Wistar (Rattus Novergicus) adultos foram aleatoriamente distribuídos em 4 grupos: Grupo 1 (n=08): DM+TO+PE; Grupo 2 (n=08): DM+TO; Grupo 3 (n=08): não-diabético+TO+PE; Grupo 4 (n=08): não diabético+TO. O DM foi induzido nos animais do G1 e G2 pela injeção intraperitoneal de 60 mg/kg de estreptozotocina (STZ). Dez dias após a indução do DM, os animais do G1 foram induzidos à PE pela colocação da ligadura de fio de seda no sulco dos primeiros molares inferiores do lado esquerdo (lado teste); o mesmo foi feito nos animais não diabéticos (G3). O molar contralateral (direito) de todos os animais dos 4 grupos serviu como controle. O início da indução do TO, pela cimentação do fio ortodôntico na oclusal dos molares já submetidos à PE, se deu 15 dias após a colocação da ligadura (G1 e G3). No mesmo dia o TO também foi induzido nos grupos sem ligadura (G2 e G4) permanecendo por 10 dias até a data do sacrifício. A avaliação intra-grupo mostrou haver diferença estatística significante de perda óssea alveolar quando comparado os dentes do lado teste (TO) ao lado controle (p<0,0001) em todos os grupos (G1, G2, G3 e G4). A avaliação intergrupo mostrou diferenças estatísticas significantes (p<0,05) entre G1 e G2 e entre G3 e G4, com reabsorção óssea mais severa para os grupos com TO+PE quando comparados aos grupos com TO. A média de reabsorção óssea do G1 (DM+ TO+PE) foi significantemente maior (p<0,05) do que a do G3 (TO+PE). Não foram detectadas diferenças estatísticas significantes (p>0,05) entre G2 (DM+TO) e G4 (TO). Dentro dos limites deste estudo pôde-se concluir que o diabetes mellitus agrava a perda óssea alveolar nos animais com trauma oclusal quando associado à periodontite experimental. / Abstract: The aim of this study was to evaluate the diabetes mellitus (DM) effects on alveolar bone resorption induced by occlusal trauma (OT) with or without experimental periodontites (EP) in rats. Thirty-two adult male rats (Rattus Novergicus) were randomly assigned to one of four groups: Group1 (n=08): DM+OT+EP; Group 2 (n=08): DM+OT: Group 3 (n=08): OT+EP: Group 4 (n=08): OT. Experimental DM was created by intraperitoneal injection of 60 mg/kg body weight streptozotocin (STZ) in G1 and G2. Ten days after diabetes induction, the animals in G1 received a silk ligature in the sulcular area of their mandible left first molar (test side (OT) to induce EP; the same was performed with the non-diabetics animals (G3). The contralateral molar (right side) was left as a control in all of the groups. G1 and G3 were submitted to OT induction (by orthodontic wire bonding in the occlusal molar surface) after fifteen days period. At the same day, the OT was also inducted in the groups (02 and 04) without ligature. The animals were sacrificed 10 days later. The intragroup analysis revealed significant difference between teeth in the test side (OT) and control side (p<0.05) among the 4 groups (G1. G2. G3. G4). The test side (OT) showed higher levels of bone resorption. The histometrics results showed significant difference (p< 0.05) between G1 and 02 and between 03 and G4, with more severe resorption for the groups with OT+EP compared do OT. For the histological analysis, 01 (DM+OT +EP) showed more bone loss when compared to G3 (OT +EP) (p<0.05). No difference was observed (p<0.05) between G2 (DM+OT) and G4 (OT). Within the limit of the study, it was concluded that diabetes mellitus enhances the alveolar bone loss in animals with occlusal trauma associate to experimental periodontitis. / Mestrado / Periodontia / Mestre em Clínica Odontológica

Die Chemotherapie eines Nebennierenrindenkarzinomes gestaltet sich als insgesamt schwierig, da nur wenige prognostische Faktoren existieren. Ein mögliches Chemotherapie-Regime beinhaltet Streptozotocin, ein alkylierendes Chemotherapeutikum, welches Guanin in Methylguanin alkyliert. Das andere verwendete Therapieregime umfasst EDP. Die FIRM-ACT Studie war die erste randomisierte Studie, welche die beiden Chemotherapie Regime EDP und STZ in Kombination mit Mitotan in der Behandlung des fortgeschrittenen ACC analysierte. Hier konnte ein signifikant längeres progressionsfreies Überleben bei der Behandlung mit EDP + M (5 Monate) vs. STZ + M (2,1 Monate) festgestellt werden. Ein objektives Ansprechen des Tumors zeigte sich bei EDP + M bei (35 von 151 Patienten) und bei STZ + M bei (14 von 153) Patienten. Es folgte daher die Empfehlung im Versorgungsalltag EDP + M als Erstlinientherapie einzusetzen. Zur Evaluierung eines möglichen Ansprechens von STZ wurde der Methylierungsstatus von MGMT analysiert. MGMT ist ein Protein, welches Alkylierungen durch Bindung entfernt und repariert Methylguanin in Guanin. Eine Hypermethylierung führt zu einer reduzierten Expression von MGMT und folglich zu einer verminderten Reparaturkapazität. Dies führt insgesamt zu einem besseren Ansprechen der alkylierenden Chemotherapie mit längerem progressionsfreiem Überleben und Gesamtüberleben. In der Kohorte konnten dabei zwei Amplicons des MGMT-Gens mit einem statistisch signifikanten Unterschied zwischen Responder und Non-Responder festgestellt werden. Zudem untersuchten wir die Expression von GLUT-2, welcher STZ über die Zellmembran transportiert. Vier der untersuchten Proben zeigten jedoch keine membranäre Expression, diese waren Non-Responder, sodass die membranäre Expression von GLUT-2 eine erste Voraussetzung für die Aufnahme von STZ in Tumorzellen zu sein scheint. Entsprechend der Ergebnisse kann davon ausgegangen werden, dass der Methylierungsstatus der Promotorregion des MGMT-Gens als prognostischer Faktor zur Therapieentscheidung mit STZ hinzugezogen werden sollte, wenn die Tumorzellen GLUT-2 membranär exprimieren. Insgesamt könnte dies der erste Schritt einer individualisierten/stratifizierten Chemotherapie beim fortgeschrittenen ACC mit STZ sein. / The cytotoxic treatment of adrenocortical carcinoma (ACC) is challenging, and only a few prognostic indicators are available. One of the established cytotoxic treatments involves the use of streptozotocin (STZ). STZ is an alkylating agent that methylates guanine to form methylguanine. Another treatment option consists of etoposide, doxorubicin, and platin (EDP). The FIRM ACT Study was the first international randomized study to compare these therapeutic regimes in combination with mitotane (M). The results of the FIRM ACT Study revealed a significantly longer progression-free survival (PFS) in the EDP + M treatment group (5 months) compared to the STZ + M group (2,1 months). Additionally, a higher rate of objective tumor response (ORR) was achieved in the EDP + M group (35 out of 151 patients) compared to the STZ + M group (14 out of 152 patients). As a conclusion of the study, EDP + M was recommended in therapy guidelines as first-line therapy in the cytotoxic treatment of ACC. Overall, however, the study results also indicate, especially due to no statistically significant differences in overall survival (OS), that there are indeed patients who benefit from therapy with STZ + M. To identify patients who might benefit from STZ + M treatment, the methylation status of the methylguanine DNA methyltransferase (MGMT) promoter was examined. MGMT is a protein responsible for repairing methylguanine to guanine. Hypermethylation of the MGMT gene leads to reduced production of MGMT and a decreased capacity to repair methylguanine. This in turn may result in a better response to alkylating cytotoxic treatment, potentially leading to longer PFS and OS. Within the examined cohort, two regions of the MGMT gene showed significantly higher methylation in patients who responded to STZ therapy compared to the non-responder group. Furthermore, the expression of GLUT-2 (a glucose transporter) was assessed using immunohistochemical staining of the tumor cells. GLUT-2 enables the transport of STZ into the cells. In the analyzed cohort, four patients showed no GLUT-2 staining, and all of them were non-responder. This suggests that GLUT-2 plays a crucial role in STZ treatment. Based on the examination results, the presence of GLUT-2 is a primary requirement to predict a potential response to STZ. The subsequent step involves assessing the promoter methylation status of MGMT, which serves as a prognostic factor in deciding the treatment approach for ACC with STZ. This could mark the initial steps in the process of personalizing and stratifying cytotoxic treatment for ACC using STZ.

Die vorliegende Arbeit untersucht den Effekt des Guanylatzyklase-Aktivators HMR1766 auf die vaskuläre Dysfunktion bei Streptozotozin-(STZ-)induziertem Diabetes mellitus im experimentellen Rattenmodell. Zunächst wird anhand funktioneller Studien die vaskuläre Reaktivität aortaler Gefäßringe gesunder, Placebo- und HMR1766-behandelter Tiere verglichen. Davon ausgehend werden weiterführende experimentelle Daten dargestellt, die mögliche Wirkungsmechanismen von HMR1766 im STZ-Diabetes-Modell beschreiben und einen Erklärungsansatz für die funktionell gewonnenen Daten liefern. Es wird gezeigt, dass eine chronische Behandlung mit HMR1766 die endotheliale Dysfunktion im STZ-Diabetes signifikant verbessern kann. HMR1766 verstärkt den Stickstoffmonoxid-(NO-)Signalweg über die lösliche Guanylatzyklase zum zyklischen Guanosinmonophosphat (cGMP), normalisiert die eingeschränkte Vasorelaxation, führt zu einer gesteigerten NO-Bioverfügbarkeit und erhöht so die inhibitorische Wirkung von NO auf die Superoxid-produzierende NADPH-Oxidase. Dadurch wird der oxidative Stress signifikant reduziert und die NO-Inaktivierung durch Superoxid verringert. Die vorgelegten Daten stellen ferner einen Zusammenhang her zwischen dem vaskulären Kontraktionsdefizit bei Diabetes und einem Ungleichgewicht im Arachidonsäuremetabolismus. Durch eine Überexpression von Cytochrom-P450-2E1 (CYP2E1) im STZ-Modell kommt es zu einem Defizit der vasokonstriktorisch wirkenden 20-Hydroxyeicosatetraensäure (20-HETE). Dies führt zu einem verminderten Ansprechen der Gefäße auf Vasokonstriktoren wie Phenylephrin. HMR1766 kann durch die Verbesserung des NO/cGMP-Signals die katalytische Aktivität von CYP2E1 hemmen, dadurch das 20-HETE-Defizit ausgleichen und die vaskuläre Reaktivität wieder normalisieren. Zusammenfassend zeigen die dargestellten Ergebnisse, dass eine Behandlung mit HMR1766 bei STZ-induziertem Diabetes mellitus zu einer signifikanten Verbesserung der vaskulären Dysfunktion führt. Eine Behandlung mit HMR1766 könnte daher ein sinnvoller Ansatz sein zur Vermeidung vaskulärer Komplikationen bei Diabetes mellitus. / Background: Vascular endothelial dysfunction and the so-called non-contractile phenotype of smooth muscle cells are well described in diabetes mellitus. Endothelial dysfunction results in decreased signalling through the NO/sGC/cGMP-pathway leading to decreased levels of cGMP in diabetes. This study investigated in STZ-diabetic rats whether chronic stimulation of guanylyl cyclase with the novel activator HMR1766 would improve vascular reactivity in diabetes. Results: Endothelium-dependent as well as endothelium-independent nitric oxide-mediated vasorelaxation was significantly impaired in diabetic placebo-treated animals and was completely normalized by treatment with HMR1766, indicating improved signalling through the NO/sGC/cGMP-signalling cascade. NOS-inhibitor-induced contraction of slightly preconstricted aortic rings was significantly attenuated in diabetic animals indicating reduced NO-bioavailability. This was also normalized by treatment with HMR1766. Oxidant stress is a major cause of reduced endothelial NO-bioavailability in diabetes. Increased expression of NAD(P)H-oxidase subunits was demonstrated in this study, resulting in enhanced oxidative stress and reduced NO-bioavailability. Chronic treatment with HMR1766 reduced the enhanced superoxide formation and expression of the NAD(P)H-oxidase subunit gp91phox in STZ-diabetic aortae. Diabetic rats displayed a highly significant reduction in vascular contraction compared to healthy control animals as described for the diabetic, non-contractile phenotype. Furthermore, this study shows that the increased expression of CYP2E1 in STZ-diabetes also contributes – due to a following imbalance in arachidonic acid metabolism and decreased levels of 20-HETE – to a decreased vasoconstriction in the aortic rings. Treatment with HMR1766 reduced the catalytic activity of CYP2E1 and normalized vascular contraction. Conclusion: Chronic guanylyl cyclase activation in diabetes improves vascular relaxation and contraction by improving release of and sensitivity for nitric oxide. HMR1766 significantly enhanced the reduced signaling through the NO/sGC/cGMP-pathway in diabetes and might be a new potential therapeutic approach for treatment of vascular dysfunction in diabetes.

Thesis (M.S.)--University of Michigan, 1975.

Thesis (M.S.)--University of Michigan, 1975.

As doenças periodontais (DPs) são alterações inflamatórias crônicas que acometem os tecidos de sustentação do órgão dental. A presença do diabetes é refletida em maior severidade e prevalência das DPs tanto em humanos quanto em modelos experimentais. Contudo, os mecanismos biológicos envolvidos no aumento da prevalência e da severidade permanecem pouco conhecidos. Desta forma, o objetivo deste estudo foi avaliar o número de células marcadas por imunohistoquímica para TNF-&#x3B1;, RANKL, OPG, IL-10 e para o fator de transcrição RUNX-2, na doença periodontal experimental decorrente da indução do diabetes em ratos. Além disso, avaliamos os possíveis efeitos do tratamento com chá verde sobre o periodonto dos animais. Inicialmente, os ratos (n=80) foram submetidos à indução do diabetes por administração intraperitoneal de estreptozotocina (50mg/kg) e, juntamente com o grupo controle (n=40), foram subdivididos em animais tratados com chá verde ou com água, acompanhados durante o período de 15, 30, 60 ou 90 dias. Após o sacrifício dentro do tempo determinado para cada grupo, as hemimaxilas coletadas passaram pelos procedimentos de imunohistoquímica. Os resultados revelaram que a presença do diabetes causou perda óssea alveolar, compatível com o desenvolvimento da doença periodontal e resultou em alterações significativas no número de células imunomarcadas para diferentes mediadores do processo inflamatório. Entretanto, o chá verde apresentou efeitos benéficos para o periodonto, alterando a marcação das citocinas envolvidas. Nos animais diabéticos, independente do tratamento, foi observado aumento estatisticamente significativo (p<0,05 ANOVA) no número de células imunomarcadas para TNF-&#x3B1; e RANKL. Inversamente, houve menor marcação para OPG (60 e 90 dias), RUNX-2 (30, 60 e 90 dias) e para IL-10 (30, 60 e 90 dias) nos animais que ingeriram água. Porém, os diabéticos tratados com chá não demonstraram diferenças significativas em relação ao seu respectivo controle. Assim, quando comparados os grupos diabéticos tratados com água e chá, os animais que receberam o chá demonstraram significativamente (p<0,05 ANOVA) menor quantidade de células munomarcadas para TNF-&#x3B1; e RANKL em relação aqueles diabéticos tratados com água, enquanto que a marcação para OPG, RUNX-2 e IL-10 foi maior. Portanto, a desregulação na expressão de citocinas e do fator de transcrição osteoblástico parece ser um dos mecanismos biológicos envolvidos no aumento da prevalência e da severidade das doenças periodontais decorrentes do diabetes. Entretanto, o chá verde modulou a inflamação no periodonto dos animais diabéticos, apresentando-se, possivelmente, como uma alternativa terapêutica e coadjuvante ao tratamento das doenças periodontais correlacionadas ao diabetes. / Periodontal diseases (PD) are chronic inflammatory diseases leading the destruction of connective tissue and alveolar bone supporting the teeth. The establishment of diabetes increases PD prevalence and severity in humans and experimental model. However, biological mechanisms regarding to increase of prevalence and severity remains poorly known. The aim of this study was to evaluate the number of immuno-staining cells to TNF-&#x3B1;, RANKL, OPG, IL-10 and transcription factor RUNX-2 in experimental periodontal disease in diabetic rats. Furthermore, the possible green tea efects were evaluated in periodontiumof the rats. Diabetes was induced in Wistar rats (n=120) by intraperitoneal administration of 50 mg/kg ofstreptozotocin and together with control animals (n=80), the rats were subdivided in water or green tea treated group, that were analyzed at 15, 30, 60 and 90 days after diabetes induction. The animals were sacrificed and the hemimaxillae were removed and submitted to immunohistochemistry procedures. Our data demonstrated that diabetes induction and progression resulted in significant bone loss and alterations in number of immuno-staining cells to different mediators of inflammatory process. However, the green tea showed positive effects in periodontium through inflammation modulation. In diabetic rats, regardless of treatment, we observed an increased number of immuno-staining cells to TNF-&#x3B1;, IL-1b and RANKL (p<0,05 ANOVA). On the other hand, in water treated diabetic rats, there were a decreased number of immuno-staining cells to OPG (60 e 90 days), RUNX-2 (30, 60 e 90 days) and IL-10 (30, 60 e 90 days). However, the green tea treated rats did not showed statistical differences between control and experimental groups in those staining. When we compared both diabetic groups, green tea and water treated, the animals that drank the green tea showed decreased number of immuno-staining cells to TNF-&#x3B1; and RANKL(p<0,05 ANOVA) whereas the number of immuno-staining cells to OPG, RUNX-2 e IL-10 were increased. Taken together, desregulation of inflammatory cytokines and osteoblastic transcripition factor seem to be one of biological mechanisms involved in the increase of periodontal disease prevalence and severity associated with diabetes. However the green tea was able to modulate inflammation in diabetic rats periodontium and it seems to be a possible terapeutic agent to periodontal disease treatment associated with diabetes.

Made available in DSpace on 2014-06-11T19:27:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-12-15Bitstream added on 2014-06-13T18:07:11Z : No. of bitstreams: 1 manaia_cn_me_araca.pdf: 1017780 bytes, checksum: 5bfc19d12454af90b8f644211fa95235 (MD5) / Diabetes é uma desordem metabólica que interfere no tecido ósseo. Objetivou-se avaliar a fragilidade de fêmures de ratos diabéticos tipo 1 (DM1), pela densitometria e ensaio biomecânico. Foram utilizados 22 animais (Rattus novegicus, albinus, Wistar), com aproximadamente 250 gramas, divididos em grupo: Controle e Diabetes aleatoriamente. A DM1 foi inoculada pela estreptozotocina dissolvida em tampão citrato a 0,01M, pH 4,5, na concentração de 35mg/Kg na via peniana. Após 4 semanas da indução, foram sacrificados e os fêmures desarticulados. Para análise densitométrica utilizouse densitômetro DPX Lunar ™, para densidade radiográfica o sistema digital Digora®. No ensaio mecânico usou a máquina universal de ensaio EMIC® na região diafisária do fêmur. Os resultados passaram por análise estatística, teste t de Student, paramétrico e não pareado, onde o Conteúdo Mineral Ósseo (g), Densidade Mineral Óssea (g/cm²), Densidade Óssea (mmAl), Força Máxima (N) observadas nos fêmures de portadores de diabetes foi inferior ao grupo controle comprovado estatisticamente. Na Rigidez (x103N/m) e na Área (cm²) não houve diferença estatística. Conclui-se que o diabetes tipo 1 causou fragilidade nos fêmures dos ratos, reduzindo sua densidade mineral e consequentemente sua resistência mecânica. / Diabetes is a metabolic disorder that interferes with bone mass reducing the minerals density and consequently its mechanical strength. Our objective was to evaluate the femurs fragility in rats with type 1 diabetes (DM1)by densitometry and biomechanical tests. A total of 22 animals (Rattus novegicus, Albinus, Wistar), with approximately 250 grams were divided into group: Control and Diabetes. In-group Diabetes animals received streptozotocin dissolved in citrate buffer 0.01 M, pH 4.5, at a concentration of 35 mg/kg single dose in the penile vein. After 4 weeks of induction, the animals were sacrificed and the femurs were disarticulated for biomechanical analysis (Maximum Strength and stiffness) and densitometric analysis (Bone Mineral Density, Bone Mineral Content and Area). For densitometric analysis was used densitometer Lunar DPX ™ for the radiographic density digital Digora®. The biomechanical analysis used the universal testing machine EMIC ® in the femoral shaft. The results passed through statistical analysis, Student t test, parametric and nonpaired where of bone mineral content (g), bone mineral density (g/cm²), Bone Density (mmAl) Maximum Force (N) observed in the femurs of diabetic patients was lower than the control group accused significative differences. In Stiffness (x103N/m) and Area (cm²) there was no statistical difference.. Concluded that type 1 diabetes has caused weaknessin the femurs of mice, reducing its mineral density and consequently its mechanical strength.

Orientador: Mário Jefferson Quirino Louzada / Banca: Alessandra Aranega / Banca: Stela Márcia Mattiello Gonçalves Rosa / Resumo: Diabetes é uma desordem metabólica que interfere no tecido ósseo. Objetivou-se avaliar a fragilidade de fêmures de ratos diabéticos tipo 1 (DM1), pela densitometria e ensaio biomecânico. Foram utilizados 22 animais (Rattus novegicus, albinus, Wistar), com aproximadamente 250 gramas, divididos em grupo: Controle e Diabetes aleatoriamente. A DM1 foi inoculada pela estreptozotocina dissolvida em tampão citrato a 0,01M, pH 4,5, na concentração de 35mg/Kg na via peniana. Após 4 semanas da indução, foram sacrificados e os fêmures desarticulados. Para análise densitométrica utilizouse densitômetro DPX Lunar ™, para densidade radiográfica o sistema digital Digora®. No ensaio mecânico usou a máquina universal de ensaio EMIC® na região diafisária do fêmur. Os resultados passaram por análise estatística, teste t de Student, paramétrico e não pareado, onde o Conteúdo Mineral Ósseo (g), Densidade Mineral Óssea (g/cm²), Densidade Óssea (mmAl), Força Máxima (N) observadas nos fêmures de portadores de diabetes foi inferior ao grupo controle comprovado estatisticamente. Na Rigidez (x103N/m) e na Área (cm²) não houve diferença estatística. Conclui-se que o diabetes tipo 1 causou fragilidade nos fêmures dos ratos, reduzindo sua densidade mineral e consequentemente sua resistência mecânica. / Abstract: Diabetes is a metabolic disorder that interferes with bone mass reducing the minerals density and consequently its mechanical strength. Our objective was to evaluate the femurs fragility in rats with type 1 diabetes (DM1)by densitometry and biomechanical tests. A total of 22 animals (Rattus novegicus, Albinus, Wistar), with approximately 250 grams were divided into group: Control and Diabetes. In-group Diabetes animals received streptozotocin dissolved in citrate buffer 0.01 M, pH 4.5, at a concentration of 35 mg/kg single dose in the penile vein. After 4 weeks of induction, the animals were sacrificed and the femurs were disarticulated for biomechanical analysis (Maximum Strength and stiffness) and densitometric analysis (Bone Mineral Density, Bone Mineral Content and Area). For densitometric analysis was used densitometer Lunar DPX ™ for the radiographic density digital Digora®. The biomechanical analysis used the universal testing machine EMIC ® in the femoral shaft. The results passed through statistical analysis, Student t test, parametric and nonpaired where of bone mineral content (g), bone mineral density (g/cm²), Bone Density (mmAl) Maximum Force (N) observed in the femurs of diabetic patients was lower than the control group accused significative differences. In Stiffness (x103N/m) and Area (cm²) there was no statistical difference.. Concluded that type 1 diabetes has caused weaknessin the femurs of mice, reducing its mineral density and consequently its mechanical strength. / Mestre