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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.
1

Novel vs clinical organ preservation solutions: improved cardiac mitochondrial protection

Ferng, Alice S., Schipper, David, Connell, Alana M., Marsh, Katherine M., Knapp, Shannon, Khalpey, Zain 26 January 2017 (has links)
Background: Heart transplantation remains the gold standard for end-stage heart failure, with current ex vivo organ storage times limited to 4 to 6 h before critical tissue damage occurs. Many preservation solutions exist in an attempt to limit both ischemic and reperfusion damage. In order to compare the effects of various storage solutions, mitochondrial function can be used to provide a sensitive analysis of cellular metabolic function. Methods: Experimental plates were seeded with cardiac myoblasts and kept in suspended animation for either 4 or 8 h at either 4(o) or 21 degrees C, in Celsior (R), Perfadex (R), or Somah storage solutions. Cells were then reanimated for 1 h at 37 degrees C to simulate a reperfusion or clinical transplant scenario. Cellular bioenergetics were measured immediately thereafter to examine biochemical differences between preservation solutions and their effectiveness on preserving metabolic function. Results: The oxygen consumption rates of Somah solution were significantly higher than Celsior (R) and Perfadex (R) at 4 degrees C, with the exception of Perfadex (R) at 4(o) for 4 h. This effect was sustained up to 8 h. At 21 degrees C, oxygen consumption rates of Somah solution are significantly higher than Celsior (R) and Perfadex (R) at basal conditions after 4 h, but this effect is not sustained after 8 h. Conclusions: The purpose of this experiment was to study the efficacy of various preservation solutions on a mitochondrial level. The significantly higher oxygen consumption rates of Somah at 4 degrees C suggests that Somah solution may have the ability to protect cellular mitochondrial integrity, improve transplanted organ function by reducing ischemic-reperfusion injury, and thereby improve transplant outcomes. Given that Somah offers benefits over Celsior (R) and Perfadex (R) at 4 degrees C, it should be a target in future organ preservation solution research.
2

Efeitos do precondicionamento isquêmico associado à diferentes soluções de preservação, no intestino delgado preservado hipotermicamente / Effects of ischemic preconditioning associated with different preservation solutions, in the small bowel preserved underhypothermia

Neves, José de Souza [UNIFESP] 30 March 2011 (has links) (PDF)
Made available in DSpace on 2015-07-22T20:49:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-03-30 / INTRODUÇÃO: A preservação de enxertos intestinais é fator determinante para o sucesso dos transplantes de intestino delgado. OBJETIVO: Avaliar os efeitos do precondicionamento isquêmico associado às Soluções de Belzer, Celsior, Custodiol e Ringer-Lactato na preservação intestinal e avaliar, também, qual destas soluções, isoladamente, tem melhor desempenho. MÉTODO: Foram formados, aleatoriamente, 4 grupos de 14 ratos Wistar, machos, com peso entre 250 e 300 gramas, sendo todos submetidos à laparotomia e coleta de 20 cm de íleo, para preservação, sob hipotermia, nas soluções Ringer (RL), Celsior (Cs), Custodiol (Cust) e Belzer (Belz), por um período de 24 horas. Previamente à coleta do segmento ileal, metade dos animais de cada grupo foi submetida ao precondicionamento isquêmico do intestino delgado (PCI), que consistiu de oclusão da artéria mesentérica superior, por 10 minutos, seguido de liberação do fluxo (reperfusão) pelo mesmo período. No decorrer do período de preservação, foram coletadas amostras intestinais em 4 momentos: com Zero, 12, 18 e 24 horas. Em cada um destes momentos foram realizadas: análise do grau de lesão da mucosa (escore de Park et al.); dosagem do ácido malondialdeído (MDA), em nmol/mg de tecido; quantificação da apoptose celular nas vilosidade intestinais através de estudo imunohistoquímico, com anticorpos anti-caspase 3. Os testes estatísticos usados foram: ANOVA, Tukey, Kruskal-Wallis e Mann-Whitney. Valores de p<0,05 foram considerados significantes. RESULTADOS: Nos animais sem pci os valores do MDA, grau de lesão da mucosa e apoptose foram maiores nos grupos RL, e a apoptose celular foi menor nos grupos Cs e Belz (p<0,05). Nos grupos com pci o RL apresentou maiores valores de MDA com 18 e 24h de preservação (p<0,05). Os graus de lesão da mucosa e a apoptose, com exceção de zero h, foram maiores nos grupos RL e Cust e menores no Cs e Belz. CONCLUSÃO: As Soluções Celsior e Belzer tiveram melhores efeitos na proteção do intestino delgado e estes efeitos foram incrementados pelo PCI. / BACKGROUND: The preservation of intestinal grafts is a determining factor for the success of small intestine transplantation. OBJECTIVE: To evaluate the effects of ischemic preconditioning associated with Belzer, Celsior, Custodiol and Ringer-Lactate solution in the intestinal preservation and which of these solutions, alone, has better performance. METHODS: We formed randomly, four groups of 14 male Wistar rats weighing between 250 and 300 grams, all of then underwent laparotomy and collection 20cm of ileum for preservation under hypothermia, in Ringer solution (RL), Celsior (Cs), Custodiol (Cust) and Belzer (Belz), for a period of 24 hours. Prior to collection of the ileal segment, half the animals in each group was subjected to ischemic preconditioning of the small intestine (IPC), which consisted of occlusion of superior mesenteric artery for 10 minutes followed by release of the flow (reperfusion) for the same period. During the period of preservation, intestinal samples were collected for four times: with Zero, 12, 18 and 24 hours. In each of these moments were performed: analysis of the degree of mucosal injury (score of Park et al.); dosage of tecidual acid malondialdehyde (MDA) in nmol/mg; quantification of apoptosis in intestinal villi by immunohistochemistry with anti-caspase3. The statistical tests used were ANOVA, Tukey, Kruskal-Wallis and Mann-Whitney; p-values<0.05 were considered significant. RESULTS: In animals without ipc, MDA values, degree of mucosal injury and apoptosis were higher in RL group, and apoptosis was significantly lower in Cs and Belz (p<0.05). In groups with the ipc, RL showed higher MDA values at 18 and 24 hours of preservation (p<0.05). The grades of mucosal injury and apoptosis, except for zero hour, were higher in RL and Cust and lower in the Cs and Belz group, CONCLUSIONS: Celsior and Belzer solutions had better protective effects on intestinal graft, and these effects were augmented by ischemic preconditioning. / TEDE
3

Pharmacological activation of pro-survival pathways as a strategy for improving donor heart preservation

Kwan, Jair Chau, Clinical School - St Vincent's Hospital, Faculty of Medicine, UNSW January 2009 (has links)
Despite the development and use of specialised cardiac preservation solutions, the quality of the donor heart may still be compromised by its obligatory exposure to periods of ischaemia (both cold and warm) followed by reperfusion upon reintroduction of the recipient circulation. This is reflected in Transplant Registry data showing increased primary allograft failure as a function of increasing ischaemic time. The research described in this thesis is designed to further the understanding of the mechanisms by which the donor heart may be adapted to these prolonged periods of ischaemia and reperfusion by the activation of endogenous pro-survival signalling pathways by the addition of pharmacological agents to Celsior, a clinical preservation solution. Studies were conducted in an isolated working rat heart model of donor heart preservation. The first study investigated the cardioprotective effects of a novel inhibitor of poly(ADP-ribose) polymerase 1, INO-1153. Maximum protective effect (after a 6 hour storage period) was observed when the PARP inhibitor was administered prior to cardiac arrest and storage and when the agent was added to the Celsior cardioplegic / storage solution. This protective affect was associated with activation of the Akt signalling pathway and could be prevented by inhibition of Akt phosphorylation and activation. The second study examined functional protection and pro-survival signalling pathway activation in hearts arrested and stored for 6 hours in Celsior supplemented with glyceryl trinitrate (an exogenous source of nitric oxide) and Cariporide (an inhibitor of sodium hydrogen exchange). Here, cardiac protection was accompanied by activation of the ERK 1/2 pro-survival pathway as well as a decrease in apoptosis. The third study examined the cardioprotective effect of supplementation of Celsior with all three agents after an extended (10 hour) period of hypothermic storage. Significant recovery of function was only observed in the triply supplemented hearts, being accompanied by activation of both the Akt and ERK pathways. These studies demonstrate for the first time the feasibility of recruitment of endogenous pro-survival pathways as an approach to increasing the post-storage function of the donor heart. Importantly, for the logistics of clinical transplantation, these pathways can be recruited by addition of appropriate pharmacological agents to the arresting and storage solution.
4

Estudo comparativo entre as soluções de preservação ViaSpan® e Celsior® utilizadas em transplante de fígado.

Duca, William José 10 June 2009 (has links)
Made available in DSpace on 2016-01-26T12:51:22Z (GMT). No. of bitstreams: 1 wilsonjoseduca_tese.pdf: 1506382 bytes, checksum: 16d07e2101b80e16a2d850b2111fb461 (MD5) Previous issue date: 2009-06-10 / liver transplantation (OLT) is today the gold standard for the treatment of the end-stage liver disease. The preservation of graft is the cornerstone for the OLT with cadaveric donor. In this context, it is important to evaluate the effectiveness of different solutions used for it. Our objective was to compare the results of OLT, carried out with cadaveric donor, preserved with the solutions of preservation ViaSpan® or Celsior®. Casuistic and Method: we evaluated retrospectively 72 recipients of the OLT. Of these, 36 had their graft preserved with ViaSpanâ solution (Group A) and 36 with Celsiorâ solution (Group B) as follows: the donor was perfused in situ of 1000 ml in the portal vein of ViaSpanâ or Celsiorâ and 3000 ml of Euro-Collins in aortic artery; in the table managed ViaSpanâ or Celsiorâ 500 ml in the portal vein, 250 ml in hepatic artery and 250 ml in the biliary duct. The following variables in groups A and B were evaluated: cost of the solutions, characteristics of the donors, characteristics of the recipients, intraoperative details, reperfusion injury and esteatose of graft with biopsy carried out after the reperfusion. As results of the OLT were evaluated: grafts with primary nonfunction (PNF), initial poor function (IPF), rejection, complications of the biliary duct, complications of the hepatic artery, retransplantation, follow up of the receiver in the first year after the OLT. Results: bigger warm ischemia and duration of surgery in group A (p= 0,002 and 0.001 respectively). The cost of the Celsior solution was lower (less than U$ 266.00 per litre). The remaining: characteristics of the donors, characteristics of the recipients, reperfusion injury, steatosis, PNF, PDF, rejection, retransplantation and recipients survival had not shown significant difference in statistics. Stenosis of the biliary duct was 3 cases (8.3%) in group A and 8 (22.2%) in group B (p= 0.19) and thrombosis of the hepatic artery were 4 cases (11.1%) in group B and none in group A (p= 0.11). Conclusion: the result of OLT, performed with cadaveric donor, preserved with ViaSpanâ or Celsiorâ solutions was similar. However we observe a trend of bigger number of stenosis of the biliary duct and thrombosis of the hepatic artery in the recipients of agencies preserved with the Celsiorâ solution. Thus, we believe that more research is necessary to clarify this relation. / O transplante de fígado (TxF) é hoje o padrão ouro para o tratamento da doença hepática terminal. A preservação do enxerto é a pedra fundamental para o TxF com doador cadáver. Nesse contexto, é importante avaliar a eficácia das diferentes soluções de preservação. Nosso objetivo foi comparar os resultados de TxF, realizados com órgãos de doadores cadáver, preservados com as soluções de preservação ViaSpan® ou Celsior®. Casuística e Método: Avaliamos retrospectivamente 72 pacientes submetidos a TxF. Desses, 36 tiveram seus enxertos preservados com a solução ViaSpan&#61666; (Grupo A) e 36 com Celsior&#61666; (Grupo B) da seguinte forma: perfusão in situ de 1000 ml na veia porta de ViaSpan&#61666; ou Celsior&#61666; e 3000 ml de Euro-Collins na aorta; e na mesa administrou-se 500 ml de ViaSpan&#61666; ou Celsior&#61666; na veia porta, 250 ml na artéria hepática e 250 ml na via biliar. Avaliamos as seguintes variáveis nos grupos A e B: custo das soluções, dados dos doadores, dados dos receptores, dados do intra-operatório, lesão de preservação e esteatose do enxerto com biópsia realizada após a reperfusão. Como resultado do TxF avaliamos: falência primária (FPE) e disfunção primária do enxerto (DPE), rejeição, complicações da via biliar, complicações da artéria hepática, retransplante, sobrevida do receptor no primeiro ano de pós-transplante. Resultados: O tempo de isquemia quente e tempo cirúrgico maiores no grupo A (p= 0,002 e 0,001 respectivamente). O custo da solução Celsior&#61666; foi menor (R$ 400,00 a menos por litro). O restante dos dados dos doadores, dados dos receptores, lesão de preservação e esteatose do enxerto com biópsia realizada após a reperfusão, FPE e DPE, retransplante, sobrevida do receptor não mostraram diferença estatística. A estenose da via biliar foi de 3 (8,3%) casos no grupo A e 8 (22,2%) no grupo B (p= 0,19) e a trombose da artéria hepática foi 4 (11,1%) casos no grupo B e ausente no grupo A (p= 0,11). Conclusão: O resultado de TxF, realizado com doador cadáver, preservado com as soluções ViaSpan® ou Celsior® foi similar. Contudo observamos um maior número de estenose de via biliar e trombose arterial nos receptores de órgãos preservados com a solução Celsior&#61666;. Assim, acreditamos que sejam necessários novos trabalhos para esclarecer esta relação.

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