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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.
111

Patogênese dos distúrbios hemostáticos sistêmicos induzidos pelo veneno da serpente Bothrops jararaca / Pathogenesis of systemic hemostatic disturbances in Bothrops jararaca snake envenomation

Yamashita, Karine Miki 28 March 2013 (has links)
Acidentes pela serpente Bothrops jararaca (Bj) causam distúrbios hemostáticos em pacientes. Sabe-se que a fisiopatologia desses distúrbios é complexa, porém não se conhece a relevância das duas principais famílias de enzimas presentes no veneno de Bj com atividade anti-hemostática, as metaloproteinases e serinaproteases, para promover esses distúrbios. Além disso, a injúria local induzida no local da inoculação do veneno poderia estimular a liberação de fator tissular (TF) na circulação sanguínea, favorecendo a coagulopatia. Assim, o objetivo deste projeto foi investigar a contribuição das metaloproteinases e serinaproteases do veneno de Bj e a expressão de TF para a gênese dos distúrbios hemostáticos, utilizando um modelo experimental em ratos. O veneno de Bj foi previamente incubado com Na2-EDTA 13 mM ou AEBSF 4 mM para inibir as metaloproteinases e serinaproteases, respectivamente, e administrado pelas vias s.c. ou i.v. Após 3 e 6 h, os parâmetros hemostáticos e de expressão proteica de TF e isomerase de dissulfeto proteico (PDI) foram avaliados. Os níveis de veneno circulante se elevaram mais rapidamente no grupo injetado pela via i.v., e o tratamento do veneno com Na2-EDTA ou AEBSF não reduziu os níveis circulantes de veneno em comparação ao grupo controle com veneno. Em comparação com animais tratados com salina, houve uma queda abrupta na contagem plaquetária em todos os grupos e tempos administrados com veneno de Bj, sendo o grupo administrado pela via i.v. o que apresentou uma queda de maior intensidade. O pré- tratamento do veneno com o AEBSF não impediu o consumo plaquetário e somente o Na2-EDTA parcialmente reverteu a plaquetopenia. Por outro lado, o veneno não tratado causou consumo de fibrinogênio plasmático, geração de produtos de degradação de fibrinogênio e fibrina, prolongamento do tempo de protrombina (TP) e hemorragia no local de inoculação do veneno. No entanto, o Na2-EDTA, e não o AEBSF, bloqueou completamente esses parâmetros. Não houve redução dos níveis de fator VII ao longo do envenenamento, e seus níveis apresentou um notável aumento nos animais envenenados no grupo 6 h s.c. Ratos envenenados apresentaram notável aumento dos níveis do TF plasmáticos, que foi inibido pelo pré-tratamento com o Na2-EDTA. Houve também aumento da expressão de TF no pulmão e pele. Nos grupos injetados com veneno de Bj em 6 h ocorreu uma redução da expressão de PDI. Os resultados mostram que as metaloproteinases são componentes essenciais para o desencadeamento da coagulopatia do envenenamento. No entanto, as metaloproteinases e serinaproteases não estão diretamente envolvidas na gênese da plaquetopenia induzida pelo veneno de Bj e outros mecanismos/toxinas parecem estar envolvidos. Os resultados também demonstraram o aumento dos níveis de TF plasmático durante o envenenamento, similar àquele observado na coagulação intravascular disseminada, o que sugere a importância da geração de TF como um mecanismo para promover distúrbios sistêmicos da coagulação / Bites by Bothrops jararaca (Bj) snakes evoke hemostatic disturbances in patients. The pathophysiology of such disturbances is complex, but the importance of the major enzyme families with anti-hemostatic activity, found in Bj venom. i.e., metalloproteinases and serine proteinases, to promote them is not known. Moreover, the local injury induced at the site of venom inoculation might also stimulate tissue factor (TF) release into bloodstream, favoring the coagulopathy. The aim of this study was to investigate the contribution of metalloproteinases and serine proteinases of Bj venom, as well the TF expression to the genesis of hemostatic disturbances, using an experimental model in rats. Crude Bj venom was previously incubated with 13 mM Na2-EDTA or 4 mM AEBSF to inhibit metalloproteinases and serine proteinases, respectively, and administered s.c. or i.v. into rats. After 3 and 6 h, hemostatic parameters and TF and protein disulfide isomerase (PDI) expression were evaluated in plasma and samples of skin and lungs. Circulating venom levels increased more rapidly in i.v. group, and neither Na2-EDTA nor AEBSF treatment reduced the circulating venom levels in comparison with the control group. Platelet counts showed a marked decrease in all groups administered with Bj venom in comparison with saline-treated rats; the fall in platelet counts was more intense in animals administered i.v. with Bj venom. The pre-treatment of venom with AEBSF failed to block the fall in platelets count, and only Na2-EDTA minimally reversed thrombocytopenia. Nonetheless, non-treated venom provoked plasma fibrinogen consumption, generation of fibrin(ogen) degration products, prolongation of prothrombin time (TP), and hemorrhage at the site of venom inoculation. However, Na2-EDTA, but not AEBSF, completely blocked these parameters. Factor VII levels were not reduced during envenomation, and they showed a marked increase in envenomed rats at 6 h in the s.c. group. Envenomed rats showed a marked increase in plasma TF levels, which was also blocked by Na2-EDTA. In addition, TF expression was increased in the lung and skin samples. PDI expression in skin was reduced at 6 h in all groups treated with venom. These findings demonstrate that metalloproteinases are essential venom components involved in the Bj-induced coagulopathy. Nonetheless, metalloproteinases and serine proteases had no direct involvement in the genesis of Bj-induced thrombocytopenia and other venom mechanisms/toxins seem to be associated therein. High levels of TF in plasma may occur during snake envenomation, so that the etiopathogenesis of coagulopathy in snake envenomation resembled that of true disseminated intravascular coagulation syndrome
112

Patogênese dos distúrbios hemostáticos sistêmicos induzidos pelo veneno da serpente Bothrops jararaca / Pathogenesis of systemic hemostatic disturbances in Bothrops jararaca snake envenomation

Karine Miki Yamashita 28 March 2013 (has links)
Acidentes pela serpente Bothrops jararaca (Bj) causam distúrbios hemostáticos em pacientes. Sabe-se que a fisiopatologia desses distúrbios é complexa, porém não se conhece a relevância das duas principais famílias de enzimas presentes no veneno de Bj com atividade anti-hemostática, as metaloproteinases e serinaproteases, para promover esses distúrbios. Além disso, a injúria local induzida no local da inoculação do veneno poderia estimular a liberação de fator tissular (TF) na circulação sanguínea, favorecendo a coagulopatia. Assim, o objetivo deste projeto foi investigar a contribuição das metaloproteinases e serinaproteases do veneno de Bj e a expressão de TF para a gênese dos distúrbios hemostáticos, utilizando um modelo experimental em ratos. O veneno de Bj foi previamente incubado com Na2-EDTA 13 mM ou AEBSF 4 mM para inibir as metaloproteinases e serinaproteases, respectivamente, e administrado pelas vias s.c. ou i.v. Após 3 e 6 h, os parâmetros hemostáticos e de expressão proteica de TF e isomerase de dissulfeto proteico (PDI) foram avaliados. Os níveis de veneno circulante se elevaram mais rapidamente no grupo injetado pela via i.v., e o tratamento do veneno com Na2-EDTA ou AEBSF não reduziu os níveis circulantes de veneno em comparação ao grupo controle com veneno. Em comparação com animais tratados com salina, houve uma queda abrupta na contagem plaquetária em todos os grupos e tempos administrados com veneno de Bj, sendo o grupo administrado pela via i.v. o que apresentou uma queda de maior intensidade. O pré- tratamento do veneno com o AEBSF não impediu o consumo plaquetário e somente o Na2-EDTA parcialmente reverteu a plaquetopenia. Por outro lado, o veneno não tratado causou consumo de fibrinogênio plasmático, geração de produtos de degradação de fibrinogênio e fibrina, prolongamento do tempo de protrombina (TP) e hemorragia no local de inoculação do veneno. No entanto, o Na2-EDTA, e não o AEBSF, bloqueou completamente esses parâmetros. Não houve redução dos níveis de fator VII ao longo do envenenamento, e seus níveis apresentou um notável aumento nos animais envenenados no grupo 6 h s.c. Ratos envenenados apresentaram notável aumento dos níveis do TF plasmáticos, que foi inibido pelo pré-tratamento com o Na2-EDTA. Houve também aumento da expressão de TF no pulmão e pele. Nos grupos injetados com veneno de Bj em 6 h ocorreu uma redução da expressão de PDI. Os resultados mostram que as metaloproteinases são componentes essenciais para o desencadeamento da coagulopatia do envenenamento. No entanto, as metaloproteinases e serinaproteases não estão diretamente envolvidas na gênese da plaquetopenia induzida pelo veneno de Bj e outros mecanismos/toxinas parecem estar envolvidos. Os resultados também demonstraram o aumento dos níveis de TF plasmático durante o envenenamento, similar àquele observado na coagulação intravascular disseminada, o que sugere a importância da geração de TF como um mecanismo para promover distúrbios sistêmicos da coagulação / Bites by Bothrops jararaca (Bj) snakes evoke hemostatic disturbances in patients. The pathophysiology of such disturbances is complex, but the importance of the major enzyme families with anti-hemostatic activity, found in Bj venom. i.e., metalloproteinases and serine proteinases, to promote them is not known. Moreover, the local injury induced at the site of venom inoculation might also stimulate tissue factor (TF) release into bloodstream, favoring the coagulopathy. The aim of this study was to investigate the contribution of metalloproteinases and serine proteinases of Bj venom, as well the TF expression to the genesis of hemostatic disturbances, using an experimental model in rats. Crude Bj venom was previously incubated with 13 mM Na2-EDTA or 4 mM AEBSF to inhibit metalloproteinases and serine proteinases, respectively, and administered s.c. or i.v. into rats. After 3 and 6 h, hemostatic parameters and TF and protein disulfide isomerase (PDI) expression were evaluated in plasma and samples of skin and lungs. Circulating venom levels increased more rapidly in i.v. group, and neither Na2-EDTA nor AEBSF treatment reduced the circulating venom levels in comparison with the control group. Platelet counts showed a marked decrease in all groups administered with Bj venom in comparison with saline-treated rats; the fall in platelet counts was more intense in animals administered i.v. with Bj venom. The pre-treatment of venom with AEBSF failed to block the fall in platelets count, and only Na2-EDTA minimally reversed thrombocytopenia. Nonetheless, non-treated venom provoked plasma fibrinogen consumption, generation of fibrin(ogen) degration products, prolongation of prothrombin time (TP), and hemorrhage at the site of venom inoculation. However, Na2-EDTA, but not AEBSF, completely blocked these parameters. Factor VII levels were not reduced during envenomation, and they showed a marked increase in envenomed rats at 6 h in the s.c. group. Envenomed rats showed a marked increase in plasma TF levels, which was also blocked by Na2-EDTA. In addition, TF expression was increased in the lung and skin samples. PDI expression in skin was reduced at 6 h in all groups treated with venom. These findings demonstrate that metalloproteinases are essential venom components involved in the Bj-induced coagulopathy. Nonetheless, metalloproteinases and serine proteases had no direct involvement in the genesis of Bj-induced thrombocytopenia and other venom mechanisms/toxins seem to be associated therein. High levels of TF in plasma may occur during snake envenomation, so that the etiopathogenesis of coagulopathy in snake envenomation resembled that of true disseminated intravascular coagulation syndrome
113

Administração precoce de concentrado de fibrinogênio em pacientes politraumatizados com tromboelastometria sugestiva de hipofibrinogenemia: um estudo randomizado para avaliação de factibilidade / Early administration of fibrinogen concentrate in polytraumatized patients with thromboelastometry suggestive of hypofibrinogenemia: a randomized feasibility trial

Lucena, Lucas Siqueira de 03 October 2018 (has links)
Trata-se de um estudo randomizado para avaliação de factibilidade conduzido entre dezembro de 2015 a janeiro de 2017 com pacientes de trauma grave (Index of Shock Severity [ISS] >= 15), admitidos na sala de emergência de um grande centro de trauma. À admissão os pacientes selecionados apresentavam hipofibrinogenemia qualitativa (FIBTEM A5 <= 9 mm) além de hipotensão (pressão arterial sistólica [PAs] < 90mmHg) e taquicardia (frequência cardíaca [FC] > 100 bpm). O desfecho primário foi avaliar factibilidade, definida como a proporção dos pacientes que receberam o tratamento alocado em até 60 minutos após a randomização: reposição de concentrado de fibrinogênio (CF) na dose de 50 mg/kg de peso corporal no grupo intervenção e não receber reposição de fibrinogênio no grupo controle. Uma lista de alocação randomizada dos tratamentos foi gerada por estatístico utilizando \"software\" apropriado. A alocação do tratamento foi realizada utilizando-se envelopes opacos lacrados, numerados sequencialmente. Não houve cegamento por inviabilidade de execução logística. Um total de 84 pacientes foram avaliados para elegibilidade, 52 foram excluídos e 32 foram randomizados, sendo alocados dezesseis em cada grupo. A maioria dos pacientes selecionados foram homens (87,5%), na quarta década de vida (42 ± 15,5) e com ISS de 32 ± 7,2. Todos os pacientes incluídos receberam o tratamento conforme alocado em até 60 minutos após a randomização (100%; IC 95%, 86,7% a 100%). O fibrinogênio sérico na sala operatória (SO) foi maior no grupo intervenção em comparação ao grupo controle (190,4 ± 85,5 vs 130,2 ± 51,1; p=0,04), mas não na chegada à UTI (330,8 ± 165,1 vs 280,3 ± 130,3; p=0,43). Houve diferença estatística significativa no desfecho secundário exploratório tempo médio de internação em UTI entre o grupo experimental e grupo controle (mediana 8, intervalo interquartil [IIQ] 5,75 - 10,0 vs mediana 11, IIQ 8,5 - 16,0; p=0,02). Não houve diferença estatística em qualquer outro desfecho clínico avaliado. Não houve danos ou efeitos indesejáveis. Concluiuse que é possível realizar um estudo clínico randomizado em contexto de emergência com reposição precoce de fibrinogênio através do concentrado de fibrinogênio. O estudo foi registrado no ClinicalTrials.gov (NCT02864875) / This is a randomized feasibility trial conducted between December 2015 and January 2017 with severe trauma patients (Index of Shock Severity [ISS] >= 15) admitted to the emergency room of a large trauma center. At admission patients presented qualitative hypofibrinogenemia (FIBTEM A5 <= 9 mm), hypotension (systolic blood pressure < 90 mmHg) and tachycardia (heart rate > 100 bpm). The primary outcome was feasibility assessed by the proportion of patients receiving the allocated treatment up to 60 minutes after randomization meaning receive replacement through fibrinogen concentrate (50mg per kg of body weight) by the intervention group and not to receive an early replacement of fibrinogen by control group. A randomized allocation list of treatments was generated by a statistician using an appropriate software. The treatment allocation was performed using sealed opaque envelopes, numbered sequentially. There was no blindness because it was no feasible in our institution. A total of 84 patients were assessed for eligibility, 52 were excluded and 32 were randomized (16 allocated to each group). The majority of patients selected were men (87,5%), in the fourth decade of life (42 ± 15,5) with ISS of 32 ± 7,2. All randomized patients received treatment as allocated up to 60 minutes after randomization (100%, 95% CI, 86,7% to 100%). Serum fibrinogen was higher in the intervention group on operating room (OR) (190,4 ± 85,5 vs 130,2 ± 51,1; p=0,04) comparing to control group but this difference was not seen on intensive care unit (ICU) (330,8 ± 165,1 vs 280,3 ± 130,3; p=0,43). The length of ICU stay was smaller in the intervention group compared to the control group (median 8, IQR 5,75 - 10,0 vs median 11, IQR 8,5 - 16,0; p=0,02). There was no difference between groups in any other clinical outcomes. We registered no adverse effects related to treatment in both groups. We concluded that it is possible to perform a randomized clinical trial in an emergency setting with early fibrinogen replacement through the fibrinogen concentrate. The study was enrolled in ClinicalTrials.gov (NCT02864875)
114

Efeito do implante de etonogestrel sobre a agregação plaquetária de mulheres hígidas / Effect of etonogestrel implant on platelet aggregation in healthy women

Macedo, Carolina Sales Vieira 28 June 2004 (has links)
Introdução: Estudos iniciais sugeriram que o risco para tromboembolismo venoso (TV) era atribuído ao componente estrogênico dos contraceptivos de forma dose-dependente. Estudos epidemiológicos têm sugerido que o risco para TV é maior com contraceptivos combinados que contêm progestagênios de terceira geração (gestodeno, desogestrel) comparados com aqueles com progestagênios de segunda geração (levonorgestrel). Esses achados inesperados têm sido alvo de muitos debates sem uma explicação definitiva. Assim, a questão das diferenças nas propriedades de cada progestagênio sobre a hemostasia tem sido levantada. Apesar dos progestagênios não serem associados a alterações marcantes nos parâmetros hemostáticos, existem poucos estudos sobre os efeitos dessas drogas, especialmente os progestagênios de terceira geração, no sistema hemostático. Objetivo: Avaliar o efeito do implante subdérmico de etonogestrel sobre a agregação plaquetária de mulheres hígidas, em seis meses de tratamento. Casuística e Métodos: Vinte e quatro mulheres saudáveis e voluntárias foram selecionadas neste estudo longitudinal e prospectivo, para usar um implante contraceptivo subdérmico de etonogestrel (metabólito biologicamente ativo do desogestrel). A agregação plaquetária foi avaliada em todas as mulheres, exceto uma, no período pré-inserção e após um, três e seis meses da inserção do implante. A agregação plaquetária foi induzida com adrenalina 50 µM, colágeno 10 µg/ml, colágeno 5 µg/ml, ADP 35 µM e ADP 17,5 µM. A análise estatística foi feita com o teste de Wilcoxon para comparar a diferença entre cada período de tratamento com os valores pré-tratamento. Resultados: Houve uma redução transitória, estatisticamente significativa, na mediana do percentual máximo de agregação plaquetária de 27%, 14% e 11%, respectivamente, com colágeno 5 µg/ml, adrenalina 50 µM e colágeno 10 µg/ml, observada um mês após a inserção do implante comparado ao valor pré-inserção (p< 0,05). A agregação plaquetária com esses agonistas retornou ao seu valor basal, após seis meses da inserção. Com outros agonistas, como o ADP 35 µM e ADP 17,5 µM, não se observou o mesmo fenômeno. Conclusão: Os resultados deste estudo mostram, pela primeira vez, que o uso do implante de etonogestrel está associado à redução transitória, mas significativa, da agregação plaquetária, observada em um mês de uso do contraceptivo, a qual retorna a seus valores normais em seis meses da inserção do implante. / Introduction: Several studies have suggested that the risk of venous thromboembolism (VTE) is attributable to the estrogen component of a contraceptive in a dose-dependent manner. Recent epidemiological studies have suggested that the risk of VTE was higher with contraceptives containing third-generation progestagens (desogestrel, gestodene) when compared with second-generation progestagens (levonorgestrel). These unexpected findings have been the subject of many debates with no definitive explanation and the question of differences in hemostatic properties of each progestagen has been raised. Although progestagens are not associated with marked changes in hemostatic variables, there are few studies on the effects of these drugs, especially third-generation progestagens, on the hemostatic system. Objective: To evaluate the acute effect of a long-term contraceptive implant of etonogestrel on platelet aggregation in healthy women. Material and Methods: Twenty-four healthy volunteer women were enrolled in this prospective longitudinal study, to use a subdermal contraceptive implant of etonogestrel (the biologically active metabolite of desogestrel). Platelet aggregation was measured in all users, except one, at baseline and after 1, 3 and 6 months of treatment. Platelet aggregation was induced with 50 µM adrenalin, 10 µg/ml collagen, 5µg/ml collagen, 35 µM ADP and 17,5 µM ADP. Statistical analysis included the Wilcoxon test to compare differences between each period of treatment from baseline. Results: Statistically significant 27%, 14% and 11% reductions of platelet aggregation with 5 µg/ml collagen, 50 µM adrenalin e 10 µg/ml collagen, respectively, were observed at 1 month of treatment (p < 0,05). Platelet aggregation returned to baseline values at 6 months of treatment with these reagents. Platelet aggregation did not show any statistic difference with ADP. Conclusions: The result of this study shows for the first time that an etonogestrel implant is associated with a transitory, but significant, reduction in platelet aggregation after the first month of treatment, which returns to normal values by 6 months of therapy.
115

Determination of the biological significances of platelet factor 4 (PF4), a tumor suppressor gene encoding an angiogenesis inhibitor in multiple myeloma. / CUHK electronic theses & dissertations collection

January 2012 (has links)
多發性骨髓瘤(Multiple myeloma) 為骨髓內漿細胞異常增生的惡性腫瘤,到目前為止仍然難以治癒。其發生發展是一個複雜的多步驟事件,涉及腫瘤細胞中遺傳和表觀遺傳的改變,以及骨髓微環境的支持。現已確定骨髓瘤細胞和骨髓微環境之間的相互作用對於骨髓瘤的病理發生,以及骨髓瘤細胞的生長,遷移和抗藥性起著關鍵作用。血小根因子四(Platelet factor 4, or PF4) 是一種抗血管生成的趨化因子。它不僅在體外抑制血管內皮細胞增殖和遷移,而且在體內抑制腫瘤的生長。此前,我們發現PF4 基因在多發性骨髓瘤中等位缺失以及DNA 高度甲基化,因而導致其在骨髓瘤病人及細胞系中的表達缺失或降低。在本研究中,我們利用體內和體外實驗鑒定了PF4 對骨髓瘤細胞以及血管生成的作用,並闡明了其作用機制。 / 首先,我們在體外鑒定了PF4 在骨髓瘤細胞中的功能。我們發現PF4 抑制骨髓瘤細胞系以及從病人骨髓中分離出來的骨髓瘤細胞的生長,以及促進其凋亡。其促凋亡活性與caspase-3 和PARP 的激活有關。我們也檢測了PF4 在骨髓瘤中對血管生成的作用。我們首先分離了病人骨髓中的內皮細胞。結果顯示PF4抑制骨髓瘤內皮細胞的生長和管狀物的形成。這些結果證明PF4 在骨髓瘤中可能是一個抑癌因子。 / 接下來我們進一步檢測了PF4 在體內的抑癌功能。在第一種模型中,骨髓瘤細胞被皮下移植到重症聯合兔疫缺陷型(NOD-SCID) 小鼠中。尾靜脈注射200ngPF4 明顯的抑制了腫瘤的生長,並延長了小鼠的成活率。第二種小鼠模型稱為兔鼠融合模型(SCID-rab model) 。在這一模型中,大白兔的腿骨先被皮下移植到(NOD-SCID) 小鼠中,再將骨髓瘤細胞注射入已植入的大白兔腿骨的骨腔中。兩周後,小鼠被尾靜脈注射入20 或200ng PF4 。結果顯示200ng PF4 顯著抑制了腫瘤的生長。通過兔疫組化分析大白兔腿骨切片,我們進一步證明了PF4 在腫瘤細胞中的增瘟,凋亡以及血管生成的作用。我們的發現因此證實了PF4 是骨髓瘤中的一個抑制因子。 / 為了鑒定PF4 在骨髓瘤中的作用機制,我們用Protein/DNA 微陣列(Protein/DNA array) 分析了PF4 參與的信號通路。結果顯示PF4 調節了若干個轉錄因子,其中包括STAT3 。凝膠遷移(EMSA) 和螢光素酪報告基因(luciferase reporter assay )檢測進一步證實PF4 抑制了STAT3 的DNA 結合能力以及轉錄活性。因此PF4 可能通過抑制STAT3 信號通路而抑制骨髓瘤的生長。我們進一步發現PF4 能抑制組成性的以及自介素6 (IL-6) 誘導的STAT3的激活。我們發現PF4 下調了STAT3 下游的靶基因,包括Mc1-1, Survivin 以及血管內皮細胞生長因子(VEGF)。而過表達組成性激活的STAT3 能逆轉PF4 所誘導的細胞凋亡。在兔鼠敵合模型中,通過兔疫組化分析大白兔腿骨切片,我們發現PF4 能抑制STAT3 的入核。SOCS3 是STAT3 其中的一個抑制因子,我們發現PF4 能誘導SOCS3 的表達。而干擾掉SOCS3 能使PF4 喪失其抑制STAT3 激活的能力。這些結果表明PF4 可能通過誘導SOCS3 的表達,從而抑制STAT3 信號通路,引起骨髓瘤的生長抑制以及抗血管生成。 / 總而言之,本研究表明PF4 是骨髓髓中一個重要調節因子。在體外和體內,PF4 通過抑制STAT3 信號通路,從而抑制腫瘤細胞的生長,促進凋亡以及抑制血管生成。本文為PF4 的臨床研究,作為一種新的治療骨髓瘤藥物,提高骨髓瘤病人的治療效果提供基礎。 / Multiple myeloma (MM) is an incurable hematological malignancy characterized by accumulation of clonal plasma cells in bone marrow (BM). The development and progression of MM is a complex multistep tumorigenic event involving both genetic and epigenetic changes in the tumor cell as well as the support by the BM microenvironment. It has been well established that the physical interaction of MM cells with the BM milieu are crucial for MM pathogenesis, MM cell growth, survival, migration and drug resistance. Platelet factor 4 (PF4), a potent antiangiogenic chemokine, not only inhibits endothelial cell proliferation and migration in vitro but also solid tumor growth in vivo. Our group previously demonstrated loss of PF4 expression in patient MM samples and MM cell lines due to concurrent allelic loss and DNA hypermethylation. In this study, we characterized the effects of PF4 on MM cells and angiogenesis in the BM milieu both in vitro and in vivo and elucidated the mechanism of PF4 effects on MM. / To characterize the effects of PF4 on MM cells in vitro, assays on cell growth, cell cycle arrest and apoptosis were performed and we found that PF4 inhibited growth and induced apoptosis in both MM cell lines and MM cells from patients. The proapoptotic activity of PF4 is associated with activation of caspase-3 and poly (ADP) ribose polymerase (PARP). We also investigated the effects of PF4 on angiogenesis in MM using endothelial cells isolated from patient's BM aspirates (MMECs). Our results showed that PF4 suppressed MMECs growth and tube formation on matrigel in a dose-dependent manner. / Given the ability of PF4 to suppress MM cell growth and angiogenesis in vitro, we evaluated its tumor suppressive function in vivo. In human subcutaneously matrigel xenograft mouse model, tail vein injection of 200ng PF4 significantly reduced MM tumor growth and prolonged survival. We next used the SCID-rab mouse model which recapitulates the human BM milieu in vivo. In this model, MM cells were directly injected into the rabbit bone which was subcutaneously implanted into the NOD-SCID mice. Two weeks after injection, SCID mice were treated with various dose of PF4 (20 or 200ng per injection, three times per week) or PBS by tail vein injection. ELISA assay for hIg (lambda) showed that tumor growth in 200ng PF4-treated mice was markedly reduced by 58% compared with the control group, which was further confirmed by immunohistochemistry analysis of CD 138 staining on rabbit bone section. Consistent with the in vitro results, induction of apoptosis in MM cells and inhibition of angiogenesis by PF4 could also be demonstrated in vivo, as evidenced by the findings on ki67, Cleaved caspase-3, CD31 and VEGF staining on rabbit bone sections from treated versus control mice. Our findings thus confirmed that PF4 is a novel tumor suppressor in MM. / However, the molecular mechanism of how PF4 inhibits MM tumorigenesis is still unclear. To identify the signal pathway PF4 involved in MM, Protein/DNA array was performed. We found that PF4 regulated several transcription factors including STAT3 in U266 cells. EMSA and luciferase reporter assay further confirmed that PF4 suppressed STAT3 DNA binding and transcriptional activity. So it is possible that PF4 mediates its tumor suppressive function, through suppressing STAT3 pathway in MM cells. We further found that pre-treatment of PF4 blocked both constitutive and interleukin-6-induced STAT3 activation in a time-dependent manner in human MM cells. PF4 could also down-regulate the STAT3-regulated gene products including Mcl-I, Survivin and vascular endothelial growth factor (VEGF). Moreover, enforced expression of constitutively active STAT3 rescued cells from PF4-induced apoptosis. In SCID-rab mouse model, we also found that PF4 inhibited STAT3 nuclear translocation by immunostaining of rabbit bone sections. When examined further, we found that PF4 induced the expression of one of the STAT3 inhibitor SOCS3, and gene silencing of SOCS3 by small interfering RNA abolished the ability of PF4 to inhibit STAT3 activation, suggesting a critical role of SOCS3 in the action of PF4. Our findings therefore suggest that by inducing SOCS3 expression, PF4 abrogates STAT3 activity, thus induces tumor growth inhibition and anti-angiogenesis. / Together, these novel studies have shown that PF4 is an important regulator of MM tumorigenesis. By abrogating STAT3 signaling it targets cell growth, induces apoptosis, suppresses angiogenesis both in vitro and in vivo in MM. These scientific observations provide the framework for clinical studies of this chemokine, as a novel drug for treatment of MM to improve patient outcome in MM. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Liang, Pei. / "November 2011." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 139-161). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Abstract in English --- p.I / Abstract in Chinese --- p.IV / List of Publications --- p.VI / Acknowledgements --- p.VII / List of abbreviations --- p.IX / List of Tables --- p.XII / List of Figures --- p.xm / Table of Contents --- p.XV / Chapter Chapter1 --- Introduction and Literature Review --- p.1 / Chapter 1.1 --- Multiple myeloma-General description --- p.1 / Chapter 1.1.1 --- Epidemiology of MM --- p.1 / Chapter 1.1.2 --- Stages of MM --- p.1 / Chapter 1.2 --- The bone marrow (BM) microenvironment in MM --- p.3 / Chapter 1.3 --- Signal pathways in MM cells --- p.5 / Chapter 1.3.1 --- JAK/STAT3 in cancers and MM --- p.5 / Chapter 1.3.1.1 --- IL-6 and its receptor --- p.7 / Chapter 1.3.1.2 --- Activation of downstream signals-The "on" signals --- p.9 / Chapter 1.3.1.3 --- Inactivation of downstream signaling --- p.11 / Chapter 1.3.1.3.1 --- Phosphatases --- p.12 / Chapter 1.3.1.3.2 --- SOCS family --- p.13 / Chapter 1.3.1.3.3 --- The PIAS family --- p.14 / Chapter 1.3.2. --- NF-κB pathway --- p.15 / Chapter 1.3.3 --- RAS-MAPK pathway --- p.17 / Chapter 1.3.4 --- Phosphatidyl inositol-3 kinase (PI3K)/AKT --- p.18 / Chapter 1.4 --- Angiogenesis in MM --- p.18 / Chapter 1.4.1 --- The process of angiogenesis --- p.18 / Chapter 1.4.2 --- Angiogenesis in caner --- p.20 / Chapter 1.4.3 --- Angiogenesis in MM --- p.22 / Chapter 1.5 --- Animal models in MM --- p.24 / Chapter 1.6 --- Treatment of MM --- p.27 / Chapter 1.6.1 --- Chemotherapy --- p.27 / Chapter 1.6.2 --- Autologous stem cell transplantation --- p.28 / Chapter 1.6.3 --- Biologically based therapies --- p.28 / Chapter 1.7 --- Platelet factor 4 (PF4) --- p.30 / Chapter 1.8 --- Structure of PF 4 --- p.30 / Chapter 1.9 --- Role of PF4 in physiological process --- p.32 / Chapter 1.9.1 --- Inhibition of megakaryocytopoiesis --- p.32 / Chapter 1.9.2 --- PF4 and coagulation --- p.33 / Chapter 1.10 --- Role of PF4 in pathological process --- p.34 / Chapter 1.10.1 --- PF4 and cancer --- p.34 / Chapter 1.10.2 --- PF4 is an angiogenic inhibitor --- p.35 / Chapter 1.11 --- Clinical applications of PF4 --- p.37 / Chapter 1.12 --- Summary and project aims --- p.37 / Chapter Chapter 2 --- Materials and Methods --- p.40 / Chapter 2.1 --- Reagents and antibodies --- p.40 / Chapter 2.2 --- MM Cell lines --- p.40 / Chapter 2.3 --- CD138⁺ primary MM cells --- p.41 / Chapter 2.4 --- CD31⁺ MM endothelial cells (MMECs) --- p.42 / Chapter 2.5 --- WST-1 assay --- p.43 / Chapter 2.6 --- Trypan blue exclusion --- p.43 / Chapter 2.7 --- Cell cycle analysis --- p.44 / Chapter 2.8 --- Apoptosis analysis --- p.44 / Chapter 2.9 --- In vitro tube formation assay --- p.45 / Chapter 2.10 --- SCID-rab mice model --- p.45 / Chapter 2.10.1 --- Construction of SCID-rab mice --- p.45 / Chapter 2.10.2 --- Establishment and monitoring of myeloma in SCID-rab mice --- p.46 / Chapter 2.10.3 --- Enzyme-linked immunosorbent assay (ELISA) --- p.46 / Chapter 2.10.4 --- PF4 treatment --- p.47 / Chapter 2.10.5 --- Immunohistochemistry --- p.48 / Chapter 2.11 --- Protein/DNA arrays --- p.49 / Chapter 2.12 --- Electrophoretic mobility shift assay (EMSA) --- p.50 / Chapter 2.13 --- Luciferase reporter assay --- p.52 / Chapter 2.14 --- Western blotting --- p.53 / Chapter 2.15 --- RNA extraction --- p.54 / Chapter 2.16 --- Real-time Polymerase Chain Reaction (Real-time PCR) --- p.54 / Chapter 2.17 --- Nuclear transfection --- p.55 / Chapter 2.18 --- Statistical analysis --- p.55 / Chapter Chapter3 --- The role of PF4 in MM: in vitro studies --- p.58 / Chapter 3.1 --- Results --- p.58 / Chapter 3.1.1 --- PF4 inhibited growth of human MM cell lines --- p.58 / Chapter 3.1.2 --- PF4 did not cause cell cycle arrest --- p.59 / Chapter 3.1.3 --- PF4 induced apoptosis of myeloma cell lines --- p.63 / Chapter 3.1.4 --- PF4 caused cell apoptosis in primary MM cells cultured in vitro --- p.64 / Chapter 3.1.5 --- PF4 suppressed MMECs growth --- p.69 / Chapter 3.1.6 --- PF4 suppressed MMECs tube formation --- p.69 / Chapter 3.2 --- Discussion --- p.73 / Chapter 3.2.1 --- Negative regulation of PF4 in MM cells growth in vitro --- p.73 / Chapter 3.2.2 --- PF4 induces apoptosis in MM cell lines and primary MM cells --- p.74 / Chapter 3.2.3 --- PF4 inhibits angiogenesis in MM in vitro --- p.76 / Chapter 3.3 --- Summary --- p.79 / Chapter Chapter4 --- The role ofPF4 in MM tumorigenesis: in vivo studies --- p.82 / Chapter 4.1 --- Results --- p.82 / Chapter 4.1.1 --- PF4 inhibited MM tumor growth and prolonged survival in subcutaneous matrigel xenograft model --- p.82 / Chapter 4.1.2 --- PF4 inhibited MM tumor growth and prolonged survival in SCID-rab mouse model --- p.85 / Chapter 4.1.3 --- PF4 reduced human MM cell proliferation, angiogenesis and induced apoptosis in SCID-rab mice --- p.88 / Chapter 4.2 --- Discussion --- p.91 / Chapter 4.2.1 --- PF4 inhibited human tumor growth in subcutaneous matrigel xenograft mouse model --- p.91 / Chapter 4.2.2 --- SCID-rab mouse model was successfully established and PF4 inhibited human MM turnor growth in this model --- p.92 / Chapter 4.2.3 --- PF4 inhibited human MM cell proliferation, angiogenesis and induced apoptosis in SCID-rab mice --- p.95 / Chapter 4.3 --- Summary --- p.96 / Chapter Chapter 5 --- The molecular mechanisms of PF4 in MM tumorigenesis --- p.98 / Chapter 5.1 --- Results --- p.98 / Chapter 5.1.1 --- ProteinlDNA array hybridization and Quantification of protein/DNA array spots --- p.98 / Chapter 5.1.2 --- PF4 suppressed DNA binding and transcriptional activity of STAT3 --- p.102 / Chapter 5.1.3 --- PF4 inhibited constitutive STAT3 phosphorylation in MM cells --- p.104 / Chapter 5.1.4 --- PF4 inhibited IL-6-induced STAT3 activation --- p.105 / Chapter 5.1.5 --- PF4 suppressed STAT3 regulated gene expression --- p.107 / Chapter 5.1.6 --- Enforced expression of constitutively active STAT3 rescued cells from PF4-induced apoptosis --- p.109 / Chapter 5.1.7 --- PF4 induced the expression of SOCS3 --- p.111 / Chapter 5.1.8 --- PF4-induced inhibition of STAT3 activation was reversed by gene silencing of SOCS3 --- p.111 / Chapter 5.1.9 --- PF4 inhibited nuclear accumulation of STAT3 and induced expression of SOCS3 in vivo --- p.114 / Chapter 5.2 --- Discussion --- p.115 / Chapter 5.2.1 --- PF4 regulated several TFs --- p.115 / Chapter 5.2.2 --- PF4 inhibited constitutive activation of STAT3 --- p.118 / Chapter 5.2.3 --- PF4 inhibited IL-6 induced activation of STAT3 --- p.120 / Chapter 5.2.4 --- PF4 suppressed STAT3 regulated gene expression --- p.121 / Chapter 5.2.5 --- PF4 induced the expression of SOCS3 --- p.124 / Chapter 5.3 --- Summary --- p.125 / Chapter Chapter 6 --- Conclusion and future studies --- p.128 / Chapter 6.1 --- Conclusion --- p.128 / Chapter 6.2 --- Future studies --- p.135 / Appendices --- p.137 / References list --- p.139
116

Développement d’une antithrombine modifiée inactive comme antidote des anticoagulants hépariniques / Development of inactive modified antithrombin as an antidote to heparin anticoagulants

Fazavana, Judicaël 06 December 2012 (has links)
Les héparines regroupant les héparines standards (HNF), les héparines de bas poids moléculaire(HBPM), et le fondaparinux, sont des médicaments anticoagulants. Ils potentialisent l’antithrombine (AT) : un inhibiteur physiologique de la coagulation. Leur utilisation en thérapeutique est associée à un risque hémorragique majeur. Actuellement, le sulfate de protamine est le seul antidote disponible vis-à-vis des HNF. Il est partiellement efficace vis-à-vis des HBPM, et n’a aucun effet contre le fondaparinux, qui n’a pas d’antidote jusqu’à présent. C’est dans ce contexte que nous proposons des AT modifiées inactives, mais capables de se lier aux molécules d’héparines. Ces AT déplaceraient les molécules d’héparines de l’AT plasmatique, et neutraliseraient leur effet anticoagulant. Pour produire de telles AT, nous avons choisi une approche recombinante et une approche chimique. Dans la première approche, nous avons exprimé le variant AT-N135Q-Pro394. Ce variant possède une activité anti-Xa ou anti-IIa inférieure à 0,02% en présence de dérivés hépariniques, et une affinité à l’héparine 3 fois meilleure, comparée à l’AT plasmatique. En revanche, dans l’approche chimique, nous avons modifié l’AT plasmatique par la 2,3-butanedione (AT-BD), un réactif chimique de caractérisation des arginines. Contrairement au variant, cette AT-BD a une perte d’activité anticoagulante modérée, puis une affinité à l’héparine 20 fois meilleure, comparée à l’AT plasmatique. Malgré ces différences de propriétés biochimiques, ces 2 AT modifiées neutralisent d’une façon similaire les héparines in vitro et sur un modèle murin. Par ailleurs, à l’inverse du sulfate de protamine, nos antidotes n’ont pas d’activité anticoagulante propre sur un test de céphaline activée. Ainsi, ce travail de thèse a permis non seulement de proposer les premiers et les seuls antidotes spécifiques au fondaparinux décrits, mais aussi des antidotes alternatifs pour tous les anticoagulants hépariniques. / Unfractionnated heparin (UFH), low molecular weight heparins (LMWH), and fondaparinux are used therapeutically as anticoagulants. They potentiate antithrombin (AT): a physiological inhibitor of coagulation. Their therapeutic use is associated with a major risk of bleeding. Currently, protamine sulfate is the only antidote available for UFH. It is partially effective for LMWH, and has no effect against fondaparinux, which has no antidote. So, we propose modified inactive AT, but able to bind heparin molecules as antidote of these heparins. These molecules would compete with plasmatic AT for binding to heparins, and neutralize their anticoagulant effect. To produce that AT, we realized a genetic approach and a chemical approach. In the first approach, we expressed the variant AT-N135Q-Pro394 that had an anti-Xa or anti-IIa activity below 0.02% in the presence of heparins, and heparin affinity three times higher, compared to the plasmatic AT. In the chemical approach, we modified the plasmatic AT by 2,3-butanedione (AT-BD), a chemical reagent for arginin’s characterization. The AT-BD had a moderate loss of anticoagulant activity, and a heparin affinity 20 times higher, compared to the plasmatic AT. Despite these differences in biochemical properties, these two modified AT neutralize similarly heparins in vitro and in a mouse model. Moreover, unlike protamine sulfate, our antidotes had not an intrinsic anticoagulant effect in activated partial thromboplastin test. Thus, this PhD-work offers the first and the only specific antidote described to fondaparinux, and it can be used too alternatively for all anticoagulant heparins.
117

Cross-flow filtration, transmission electron micrographic analysis and blood compatibility testing of collagen composite materials for use as vascular prostheses

Forbes, Martin J January 1980 (has links)
Thesis (Mech.E)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 355-373. / by Martin J. Forbes. / Mech.E
118

Novas estratégias de purificação dos fatores de coagulação Fator VIII e Proteína C a partir de plasma humano empregando cromatografia líquida. / New strategies of purification of coagulation Factor VIII and Protein C from human plasma using liquid chromatography.

Iwashita, Claudia 19 March 2012 (has links)
Neste trabalho estudou-se a purificação de fator VIII de coagulação (FVIII) e da Proteína C (PC) por cromatografia. Em coluna ANX Sepharose FF como primeira etapa de purificação do plasma permite a eluição do FVIII e da PC com bom fator de purificação, mas não a separação destas. Propomos a separação de FVIII e PC empregando cromatografia de afinidade a metal (IMAC) empregando Cu2+, Ni2+, Zn2+, Co2+ e Fe3+ e dessorção empregando imidazol, cloreto de amônio e variação de pH. Em colunas de Fe3+ e Ni2+ as proteínas praticamente não se ligaram à resina. Em IMAC-Co2+, a PC não é adsorvida pela resina enquanto o FVIII pode ser eluído com imidazol 100 mM. Em IMAC-Cu2+ a PC eluiu com imidazol 10mM e o FVIII com 200mM. Não foi possível eluir as proteínas nem com NH4Cl 1M nem quando o pH foi abaixado até 4,0. Em IMAC-Zn2+ a PC não é adsorvida e o FVIII eluiu com imidazol 200mM ou NH4Cl 1M. Diminuindo-se o pH, a recuperação da atividade do FVIII foi baixa. Concluímos que IMAC-Co2+ apresentou os melhores rendimentos e melhores fatores de purificação para as 2 protéinas. / In this work purification methods for the coagulation factor VIII (FVIII) and Protein C (PC) by chromatography was studied. The use of ANX Sepharose FF column as the first purification step allows the elution of FVIII and PC with good purification factors, but not its separation. We propose the separation of FVIII and PC using immobilized metal ion affinity chromatography (IMAC) using Cu2+, Ni2+, Zn2+, Co2+ and Fe3+ and desorption employing imidazole, ammonium chloride and pH variation. In the columns containing Fe3+ and Ni2+ metal ions, proteins did not adsorb to the resin. In IMAC-Co2+, PC was not adsorbed to the resin, while FVIII could be eluted with 100 mM imidazole. In IMAC-Cu2+ PC could be eluted with 10 mM imidazole and FVIII with 200 mM. It was not possible to elute the proteins from IMAC-Cu2+ column with either 1M NH4Cl or when pH was descreased to 4,0. In IMAC-Zn2+, PC was not adsorbed and FVIII could be eluted with 200 mM imidazole or 1 M NH4Cl. We conclude that IMAC-Co2+ presented the best yield and purification factors for the 2 proteins.
119

Pre-coagulation of solid organs

Daniel, Steven A., School of Medicine, UNSW January 2007 (has links)
Coagulation has and continues to be one of the most important elements in medicine. Issues from a lack of hemostasis range from poorer clinical outcomes to sudden death. The evolution of treatments for hemostasis have evolved from the use of Tamponade with direct pressure and bandages, the use of materials such as cobwebs and dust, the use of heat with hot oil or heated irons, to the use of suture, glues, plasmas, staplers, and electricity. This evolution has continued to bring about the prophylactic use of technology in an effort to prevent blood loss. This change from reactive treatments to proactive continue to be on a localized or superficial basis. One of the largest opportunities to proactively reduce blood loss in surgical patients is during the resection of solid organs such as the liver, kidney, and spleen. Few options have existed to help improve hemostasis short of the complete occlusion of blood supplying the tissue such as in the Pringle Maneuver. Recent studies have begun to show that practices such as this may have a significant detrimental effect on morbidity. It has been found that by applying radio frequency electrical energy in a particular way that large amounts of tissue can be pre-coagulated prior to resection. A series of animal and human clinical work has been completed to help evolve and confirm the method and the device that was created and refined during this effort. During the course of this work fifty-three patients were treated at four institutions on three continents. Average blood loss for liver resections performed with this pre-coagulation technique using the developed device in a multicenter control trail was 3.35 ml/cm2 as compared to 6.09 ml/cm2 (p < 0.05) for resections performed using standard surgical techniques alone. Additionally, the transection time necessary was also reduced from mean value of 27 minutes (2 -- 219 minutes) to 35 minutes (5 -- 65 minutes). Patients treated included those suffering from liver cirrhosis, fatty liver disease, and post chemotherapy fibrosis. From this work the use of pre-coagulation with methods and device developed was shown to be safe and effective for reducing the amount of blood loss and transection time during liver resections.
120

Effect of a progesterone-estrogen combination compound of factor VIII activity in the rat

Youtsey, John W. 03 June 2011 (has links)
AbstractFactor VIII activity was studied in fifteen white laboratory rats, strain CFE, which were given subcutaneous doses of a solution containing estrogenic substances and progesterone over a six week period. A modified version of the thromboplastin generation test was used in conjunction with a factor VIII-deficient plasma to test for factor VIII activity.The rat population consisted of three groups, One group received a high concentration dosage level of the hormone The other group received a lower concentration dosage level of the hormone compound. The third group served as the control and received no hormone treatment. Each of the above groups contained five test animals.Factor VIII activity increased in all the experimental animals except one, as exhibited by a reduction in the coagulation time. No increase in factor VIII activity was observed in the control group. A significant statistical difference was observed between the experimental rats and those of the control. The 0.05 level of statistical significance was chosen for this study.Ball State UniversityMuncie, IN 47306

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