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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

Reappraisal of Importance of the Left Internal Mammary Artery to the Left Anterior Descending Artery in Improving Mid-Term Outcome in Patients with Severe Left Ventricular Dysfunction

SONG, MIN-HO 02 1900 (has links)
No description available.
2

Type 2 diabetes impairs venous, but not arterial smooth muscle cell function: possible role of differential RhoA activity

Riches-Suman, Kirsten, Warburton, P., O'Regan, D.J., Turner, N.A., Porter, K.E. 02 March 2014 (has links)
yes / Background/purpose Coronary heart disease is the leading cause of morbidity in patients with type 2 diabetes mellitus (T2DM), frequently resulting in a requirement for coronary revascularization using the internal mammary artery (IMA) or saphenous vein (SV). Patency rates of SV grafts are inferior to IMA and further impaired by T2DM whilst IMA patencies appear similar in both populations. Smooth muscle cells (SMC) play a pivotal role in graft integration; we therefore examined the phenotype and proliferative function of IMA- and SV-SMC isolated from non-diabetic (ND) patients or those diagnosed with T2DM. Methods/materials SMC were cultured from fragments of SV or IMA. Morphology was analyzed under light microscopy (spread cell area measurements) and confocal microscopy (F-actin staining). Proliferation was analyzed by cell counting. Levels of RhoA mRNA, protein and activity were measured by real-time RT-PCR, western blotting and G-LISA respectively. Results IMA-SMC from T2DM and ND patients were indistinguishable in both morphology and function. By comparison, SV-SMC from T2DM patients exhibited significantly larger spread cell areas (1.5-fold increase, P < 0.05), truncated F-actin fibers and reduced proliferation (33% reduction, P < 0.05). Furthermore, lower expression and activity of RhoA were observed in SV-SMC of T2DM patients (37% reduction in expression, P < 0.05 and 43% reduction in activity, P < 0.01). Conclusions IMA-SMC appear impervious to phenotypic modulation by T2DM. In contrast, SV-SMC from T2DM patients exhibit phenotypic and functional changes accompanied by reduced RhoA activity. These aberrancies may be epigenetic in nature, compromising SMC plasticity and SV graft adaptation in T2DM patients.
3

Estudo de parÃmetros ecodopplercardiogrÃficos de patÃncia do enxerto composto de artÃria torÃcica interna esquerda. / Study of dopplerechocardiographic parameters of patency of the composite graft of left internal thoracic artery.

Maria ClÃudia de Azevedo LeitÃo 16 February 2011 (has links)
nÃo hà / Enxertos compostos com artÃria torÃcica interna esquerda (ATIE) tem aumentado sua aplicabilidade na cirurgia de RevascularizaÃÃo MiocÃrdica (RM). A confirmaÃÃo de patÃncia do enxerto de ATIE à pedra fundamental na RM. O melhor parÃmetro de patÃncia calculado pelo ecoDopplercardiograma à a fraÃÃo diastÃlica (FD) &#8805; 0,5. O objetivo geral deste estudo foi estabelecer parÃmetros ecoDopplercardiogrÃficos de patÃncia do enxerto composto de ATIE, quando revasculariza a artÃria interventricular anterior (AIA) e outro ramo do sistema coronariano esquerdo. O especÃfico foi definir a sensibilidade e a especificidade de trÃs variÃveis: RelaÃÃo da velocidade-pico na diÃstole sobre a velocidade-pico na sÃstole (VPD/VPS), integral da velocidade-tempo na diÃstole (VTID) e FD quanto à patÃncia do enxerto composto utilizando FD &#8805; 0,5 como padrÃo de referÃncia. O estudo foi realizado segundo um desenho em duas fases, fase controle e fase estudo. Na fase controle, todos os pacientes tinham a patÃncia dos enxertos confirmadas por cineangiocoronariografia (CINE). Estes pacientes tinham registro das variÃveis VPD/VPS, VTID e FD. Foram entÃo estabelecidos pontos de cortes para essas variÃveis baseando-se nos cÃlculos de sensibilidade e especificidade atravÃs da curva ROC (ReceiverOperationCharacteristic) com o objetivo de diferenciar enxertos compostos de enxertos simples quando a ATIE somente revasculariza a AIA. Esses pontos de corte foram aplicados nos pacientes com enxerto composto da fase estudo. Foi construÃda uma tabela de contingÃncia 2x2 para o cÃlculo de sensibilidade e especificidade, tendo como indicador de patÃncia uma FD&#8805;0,5. Na fase controle, observou-se diferenÃas estatisticamente significativas na anÃlise das trÃs variÃveis em diferenciar o enxerto simples do composto. Os parÃmetros de patÃncia do enxerto composto estabelecidos pela fase estudo foram VPD/VPS &#8805; 0,71, VTId &#8805; 0,09 e FD &#8805; 0,58. A especificidade para todas essas variÃveis foi de 100%. A sensibilidade foi de 40% para VPD/VPS &#8805; 0,71, 36,4% para VTId &#8805; 0,09 e 68% para FD &#8805; 0,58. Conclui-se que valores maiores ou iguais aos estabelecidos para cada variÃvel representam um provÃvel indicador de patÃncia do enxerto composto. Valores abaixo do estabelecido apresentam grande proporÃÃo de falsos negativos, nÃo sendo conclusivo quanto à patÃncia. / Composite grafts with left internal thoraic artery (LITA) has incresed its applicability in Coronary Artery Bypass Surgery (CAGB). Confirmation of patency of the LITA graft is the cornerstone of Miocardial Revascularization. The best measure of patency calculated by Doppler echocardiogram (Doppler) is the diastolic fraction (DF) &#8805; 0.5. The aim of this study was to establish Doppler echocardiographic parameters which could suggest the presence of a composite graft of LITA, when it revascularizes the anterior interventricular artery (AIA) and another branch of the left coronary artery system. The endpoint of this study was to define sensitivity and specificity considering three variables: ratio of peak velocity in diastole over the systolic peak velocity (DPV / SPV), the mean velocity-time integral in diastole (VTID) and FD of the composite graft patency using FD &#8805; 0.5 as the reference standard. The study was conducted according to a design in two stages. It was defined a control group and study group. In the control group, all patients had graft patencies confirmed by coronary angiography (CINE) and the variables DPV / SPV,VTID and DF measured. So, we use this data to establish cutoff points for these variables , based on the calculation of sensitivity and specificity using the ROC curve (Receiverv Operation Characteristic) in order to differentiate composite from simple graft when ATIE only revascularizes the AIA. These cutoff points were applied in patients with composite graft group study. We built a 2x2 contingency table to calculate sensitivity and specificity, considering the indicator of patency a DF &#8805; 0.5. In the control group, we observed statistically significant differences in the analysis of the three variables in differentiating simple from composite grafts. The parameters of composite graft patency established by the study group were DPV / SPV &#8805; 0.71,VTID &#8805; 0.09 and FD &#8805; 0.58. The specificity for all these variables was 100%. The sensitivity was 40% for DPV / SPV &#8805; 0.71, &#8805; 36.4% for VTId&#8805; 0.09 and 68% for FD &#8805; 0.58. We conclude that values greater than or equal to those established for each variable represents a likely indicator of graft patency compound. Values below the established are not conclusive to exclude composite grafts due to a large proportion off alse negatives.
4

Vieillissement vasculaire chez des patients athérosclérotiques: Sénescence prématurée des cellules endothéliales?

Voghel, Guillaume 03 1900 (has links)
La dysfonction de l’endothélium vasculaire, associée à une diminution de ses propriétés vasorelaxantes et anti-thrombogéniques, survient avec le vieillissement mais également chez de plus jeunes patients athérosclérotiques présentant plusieurs facteurs de risque cardiovasculaire. Au niveau cellulaire, le vieillissement des cellules endothéliales (CE) mène à un état irréversible de non division cellulaire appelé sénescence. Ces cellules sénescentes présentent des changements spécifiques au niveau de leur morphologie et de l’expression génique, menant à leur dysfonction. La sénescence dite réplicative est déclenchée par le raccourcissement des télomères survenant à chaque division cellulaire, mais peut également être induite prématurément par le stress oxydant (SIPS). L’objectif principal de cette étude est de caractériser la sénescence de CE vasculaires isolées à partir de patients athérosclérotiques, et d’observer l’impact des facteurs de risque sur cette sénescence. Afin de confirmer la contribution des deux principales voies de la sénescence, nous avons par la suite étudié conjointement ou séparément, l’impact d’un traitement chronique avec un antioxydant sur la sénescence de CE, et d’une surexpression de la sous-unité catalytique de la télomérase (hTERT), une enzyme responsable de l’allongement des télomères. Nous avons isolé et cultivé des CE provenant d’artères mammaires internes prélevées lors de pontages coronariens. Selon les études, les cellules ont été infectées ou non avec un lentivirus surexprimant la hTERT, et cultivées in vitro jusqu’à sénescence, en présence ou en absence de l’antioxydant N-acétyl-L-cystéine (NAC). Différents marqueurs des deux principales voies de la sénescence (réplicative ou SIPS) ont été quantifiés. La sénescence cellulaire se développe exponentiellement avec le temps et est associée à une réduction de la viabilité et de la prolifération cellulaires. Chez les patients athérosclérotiques, le vieillissement des CE passe par les deux principales voies de la sénescence : des télomères courts initialement en culture et la durée d’exposition in vivo aux facteurs de risque cardiovasculaire prédisent une apparition prématurée de la sénescence. Toutefois, chez les fumeurs, la sénescence est exclusivement du type SIPS. Ces facteurs de risque cardiovasculaire et principalement l’hypertension, semblent accélèrer le vieillissement biologique et favoriser la dysfonction des CE. Lorsque traitées chroniquement avec le NAC, les CE présentant initialement de moindres dommages cellulaires et moléculaires ainsi qu’une meilleure défense antioxydante développent une sénescence retardée. Lorsque le NAC est combiné à une surexpression de la hTERT, les deux voies de la sénescence sont bloquées et une immortalisation cellulaire est observée. À l’inverse, dans les CE les plus endommagées par les ROS in vivo, le NAC n’a aucun effet sur le développement de la sénescence, la hTERT, seule ou en combinaison avec le NAC, retarde légèrement la sénescence mais aucune immortalisation n’est observée lorsque ces traitements sont combinés. En conclusion, nos études démontrent que l’exposition chronique au stress oxydant associé aux facteurs de risque cardiovasculaire accélère le développement de la sénescence de CE vasculaires, contribuant potentiellement à l’athérogénèse. Dans les cellules de patients athérosclérotiques, il semble exister un seuil de dommages cellulaires et moléculaires subis in vivo au-delà duquel, aucun traitement (antioxydant ou hTERT) ne peut être bénéfique. / Vascular aging is associated with a decrease in endothelial dilatory and antithrombotic functions. This typical endothelial dysfunction, however, is also present in younger patients with cardiovascular diseases (CVD). At the cellular level, aging of healthy vascular endothelial cells (EC) leads to senescence, a state of permanent growth arrest. Senescence is characterized by specific changes in cell morphology and gene expression, which reduce EC function and thus are proposed to be pro-atherogenic. Age-associated telomere shortening leads to replicative senescence of human endothelial cells, but senescence can also be induced prematurely by oxidative stress (SIPS). Our aim was to characterize senescence of EC isolated from atherosclerotic patients and look at the influence of risk factors for CVD on the onset of senescence. To confirm the contribution of each of the two mains pathways triggering senescence, we then looked at the impact on senescence of a chronic treatment with an antioxidant combined or not with an overexpression of the catalytic subunit of telomerase (hTERT), a reverse transcriptase involved in telomere elongation. We used EC isolated from internal mammary arteries discarded during coronary bypass graft surgery. Depending on the study, EC were infected or not with a lentivirus overexpressing hTERT, and cells were cultured in vitro until senescence, in the presence or the absence of the antioxidant N-acetyl-L-cysteine (NAC). Different markers of the two main pathways of senescence (replicative ou SIS) were quantified. Senescence develops exponentially with time in culture and is associated with a decrease in cell viability and proliferation. In atherosclerotic patients, cellular aging displays an overlap between replicative and stress-induced senescence: short initial telomere length in vitro and a long exposure to risk factors for CVD in vivo predict the onset of a premature senescence. However, in smoking patients, premature senescence is exclusively induced by oxidative stress. Risk factors for CVD seem to accelerate the biological aging leading to EC dysfunction. When treated chronically with NAC, EC presenting initially lower levels of damage and a better endogenous antioxidant capacity develop a delayed senescence, probably due to a slight hTERT activation. When NAC is combined with an overexpression of hTERT, both pathways triggerring senescence are blocked and cellular immortalization is observed. In contrast, in EC presenting higher levels of damage undergone in vivo, NAC has no effect by itself on the onset of senescence, hTERT delays the onset of senescence in combination or not with NAC, but no cellular immortalization was observed in NAC-hTERT cells. In conclusion, our studies show that a chronic in vivo exposition to oxidative stress associated with risk factors for CVD accelerates the onset of vascular endothelial cells senescence that could potentially contribute to atherogenesis. EC having strong antioxidant defense capacity and DNA repair mechanisms may be rescued from replicative and stress-induced senescence unless EC have undergone an insurmountable cellular and molecular damage possibly due to uncontrolled free radical production associated with risk factors for CVD.
5

Análise comparativa da perviedade das artérias torácicas internas direita e esquerda na revascularização da região anterior do coração. Avaliação por angiotomografia no 6º mês de pós-operatório / Comparative analysis of patency of right and left internal mammary artery in the revascularization of left anterior descending and branches. Evaluation by angiography in the sixth month postoperatively

Deininger, Maurilio Onofre 04 October 2012 (has links)
Objetivos: O objetivo deste estudo é analisar a perviedade da artéria torácica interna direita (ATID) pediculada, anteroaórtica em anastomose para a região anterior do coração na cirurgia de revascularização do miocárdio (RM), em relação à artéria torácica interna esquerda (ATIE). Métodos: No período de dezembro de 2008 a dezembro de 2011, 100 pacientes foram selecionados para serem submetidos a cirurgia de RM sem circulação extracorpórea (CEC), de forma prospectiva. Eles foram agrupados em Grupo 1 (G-1) e Grupo 2 (G-2), cada um com 50 pacientes, com randomização por computador e conhecimento da técnica no início da cirurgia. No G-1, os pacientes receberam ATIE para a região anterior do coração e complementação da RM com a ATID livre para ramos da circunflexa (CX) e outros enxertos arteriais ou venosos para a coronária direita (CD) e/ou ramos. Os pacientes do G-2 receberam ATID pediculada para a região anterior do coração e complementação da RM com ATIE, pediculada, para ramos da CX e outros enxertos arteriais ou venosos para a CD e/ou ramos. A perviedade das artérias torácicas internas direita e esquerda foi avaliada através de angiotomografia coronária multislice, 64 canais, no 6º mês de pós-operatório. Resultados: Os dois grupos eram semelhantes quanto aos dados clínicos de pré-operatório, como exemplo: diabetes mellitus, hipertensão arterial sistêmica, obesidade. Os dois grupos apresentaram predominância do sexo masculino com 75,6% e 88% nos grupos 1 e 2, respectivamente. Cinco pacientes migraram do G-1 para o G-2 em virtude de doença ateromatosa na aorta ascendente e um deles foi excluído por ter que utilizar enxerto composto. A média de anastomoses distais no G-1 foi de 3,48 (DP=0,72), e no G-2 foi de 3,20 (DP=0,76). Não ocorreu mediastinite em nenhum paciente. Uma paciente do G-1 apresentou osteomielite, e necessitou de intervenção cirúrgica. Dois pacientes do G-1 foram submetidos a reoperação por sangramento. Os resultados das angiotomografias coronarianas com 96 pacientes re-estudados mostram que todas as ATIs, fosse a direita ou a esquerda, utilizadas pediculadas para a região anterior do coração encontravam-se sem oclusões ou estenoses, configurando 100% de perviedade. No G-1, um enxerto livre da ATID para ramos da CX apresentava oclusão total, em dois pacientes havia estenose leve, em um deles havia estenose moderada na anastomose proximal na aorta ascendente e outro apresentava diminuição de calibre na sua porção distal. Em três pacientes o enxerto de segmento de veia safena para ramos da CD se encontravam ocluídos. No G-2, dois pacientes apresentavam oclusão total na ATIE pediculada para ramos da CX, e outro apresentava estenose moderada na porção distal da ATIE utilizada sequencial para dois ramos marginais. Em dois pacientes o enxerto de segmento de veia safena para ramos da CD se encontravam ocluídos. Não houve óbitos em nenhum dos grupos. Conclusão: A cirurgia de RM com utilização da ATID pediculada, anterógrada para o RIA, apresenta resultado semelhante ao da ATIE utilizada para essa mesma coronária. / Objective: To analyze the patency of the pedicled, anteroaortic, right internal mammary artery (RIMA) anastomosed to the left anterior descending (LAD) and branches in coronary artery bypass graft surgery (CABG), in comparison with the left internal mammary artery (LIMA). Methods: From December 2008 to December 2011, 100 patients were selected to undergo a prospective off-pump coronary artery bypass graft surgery and were randomly divided by computer into Group 1 (G-1) and Group 2 (G-2), so that the technique was known at the beginning of the surgery. In each group, with 50 patients, the patency of both right and left internal mammary arteries, which were used pedicled to the LAD, was comparatively studied through coronary computed tomography angiography. G-1 had 50 patients who received the LIMA to the LAD or LAD/diagonal (sequential) and had the CABG complemented with the free RIMA to circumflex branches and other arterial or venous grafts to the right coronary artery (RCA) and/or branches. G-2 had 50 patients who received the pedicled RIMA to the LAD or LAD/diagonal (sequential) and had the CABG complemented with the pedicled LIMA to circumflex branches and other arterial or venous grafts to the RCA and/or branches. Results: Both groups were similar in pre-operative clinical data, such as: diabetes mellitus, systemic arterial hypertension, obesity. Also, there was predominance of males in both groups, with 75,6% and 88% in Groups 1 and 2 respectively. Five patients were switched from G-1 to G-2 owing to atheromatous disease in the ascending aorta, and one of them was dropped for having to use composite graft. The average of distal anastomosis in G-1 was 3,48 (standard deviation (SD=0,72) and in G-2 was 3,20 (SD=0,76). Mediastinitis didn\'t occur in any patient. A patient from G-1 had osteomyelitis that required surgical intervention. Two patients from G-1 underwent reoperation because of bleeding. The 64-slice coronary computed tomography angiography was performed in the 6th postoperative month; 96 patients have been re-studied so far and all pedicled IMAs to the LAD were patent. In G-1 a free RIMA graft to the circumflex branches presented total occlusion, another two had a discreet stenosis and in one moderate at the proximal anastomosis and one more had a string signal at the distal portion. In G-2 two patients had total occlusion of the pedicled LIMA to circumflex artery branches, and another one presented moderate stenosis at its distal portion. In two patients the saphenous vein graft to the RCA branches were occluded. There were no deaths in any of the groups. Conclusion: The CABG surgery using the pedicled, anteroaortic RIMA to the LAD has a similar outcome to that of the LIMA used for this same coronary.
6

Vieillissement vasculaire chez des patients athérosclérotiques: Sénescence prématurée des cellules endothéliales?

Voghel, Guillaume 03 1900 (has links)
La dysfonction de l’endothélium vasculaire, associée à une diminution de ses propriétés vasorelaxantes et anti-thrombogéniques, survient avec le vieillissement mais également chez de plus jeunes patients athérosclérotiques présentant plusieurs facteurs de risque cardiovasculaire. Au niveau cellulaire, le vieillissement des cellules endothéliales (CE) mène à un état irréversible de non division cellulaire appelé sénescence. Ces cellules sénescentes présentent des changements spécifiques au niveau de leur morphologie et de l’expression génique, menant à leur dysfonction. La sénescence dite réplicative est déclenchée par le raccourcissement des télomères survenant à chaque division cellulaire, mais peut également être induite prématurément par le stress oxydant (SIPS). L’objectif principal de cette étude est de caractériser la sénescence de CE vasculaires isolées à partir de patients athérosclérotiques, et d’observer l’impact des facteurs de risque sur cette sénescence. Afin de confirmer la contribution des deux principales voies de la sénescence, nous avons par la suite étudié conjointement ou séparément, l’impact d’un traitement chronique avec un antioxydant sur la sénescence de CE, et d’une surexpression de la sous-unité catalytique de la télomérase (hTERT), une enzyme responsable de l’allongement des télomères. Nous avons isolé et cultivé des CE provenant d’artères mammaires internes prélevées lors de pontages coronariens. Selon les études, les cellules ont été infectées ou non avec un lentivirus surexprimant la hTERT, et cultivées in vitro jusqu’à sénescence, en présence ou en absence de l’antioxydant N-acétyl-L-cystéine (NAC). Différents marqueurs des deux principales voies de la sénescence (réplicative ou SIPS) ont été quantifiés. La sénescence cellulaire se développe exponentiellement avec le temps et est associée à une réduction de la viabilité et de la prolifération cellulaires. Chez les patients athérosclérotiques, le vieillissement des CE passe par les deux principales voies de la sénescence : des télomères courts initialement en culture et la durée d’exposition in vivo aux facteurs de risque cardiovasculaire prédisent une apparition prématurée de la sénescence. Toutefois, chez les fumeurs, la sénescence est exclusivement du type SIPS. Ces facteurs de risque cardiovasculaire et principalement l’hypertension, semblent accélèrer le vieillissement biologique et favoriser la dysfonction des CE. Lorsque traitées chroniquement avec le NAC, les CE présentant initialement de moindres dommages cellulaires et moléculaires ainsi qu’une meilleure défense antioxydante développent une sénescence retardée. Lorsque le NAC est combiné à une surexpression de la hTERT, les deux voies de la sénescence sont bloquées et une immortalisation cellulaire est observée. À l’inverse, dans les CE les plus endommagées par les ROS in vivo, le NAC n’a aucun effet sur le développement de la sénescence, la hTERT, seule ou en combinaison avec le NAC, retarde légèrement la sénescence mais aucune immortalisation n’est observée lorsque ces traitements sont combinés. En conclusion, nos études démontrent que l’exposition chronique au stress oxydant associé aux facteurs de risque cardiovasculaire accélère le développement de la sénescence de CE vasculaires, contribuant potentiellement à l’athérogénèse. Dans les cellules de patients athérosclérotiques, il semble exister un seuil de dommages cellulaires et moléculaires subis in vivo au-delà duquel, aucun traitement (antioxydant ou hTERT) ne peut être bénéfique. / Vascular aging is associated with a decrease in endothelial dilatory and antithrombotic functions. This typical endothelial dysfunction, however, is also present in younger patients with cardiovascular diseases (CVD). At the cellular level, aging of healthy vascular endothelial cells (EC) leads to senescence, a state of permanent growth arrest. Senescence is characterized by specific changes in cell morphology and gene expression, which reduce EC function and thus are proposed to be pro-atherogenic. Age-associated telomere shortening leads to replicative senescence of human endothelial cells, but senescence can also be induced prematurely by oxidative stress (SIPS). Our aim was to characterize senescence of EC isolated from atherosclerotic patients and look at the influence of risk factors for CVD on the onset of senescence. To confirm the contribution of each of the two mains pathways triggering senescence, we then looked at the impact on senescence of a chronic treatment with an antioxidant combined or not with an overexpression of the catalytic subunit of telomerase (hTERT), a reverse transcriptase involved in telomere elongation. We used EC isolated from internal mammary arteries discarded during coronary bypass graft surgery. Depending on the study, EC were infected or not with a lentivirus overexpressing hTERT, and cells were cultured in vitro until senescence, in the presence or the absence of the antioxidant N-acetyl-L-cysteine (NAC). Different markers of the two main pathways of senescence (replicative ou SIS) were quantified. Senescence develops exponentially with time in culture and is associated with a decrease in cell viability and proliferation. In atherosclerotic patients, cellular aging displays an overlap between replicative and stress-induced senescence: short initial telomere length in vitro and a long exposure to risk factors for CVD in vivo predict the onset of a premature senescence. However, in smoking patients, premature senescence is exclusively induced by oxidative stress. Risk factors for CVD seem to accelerate the biological aging leading to EC dysfunction. When treated chronically with NAC, EC presenting initially lower levels of damage and a better endogenous antioxidant capacity develop a delayed senescence, probably due to a slight hTERT activation. When NAC is combined with an overexpression of hTERT, both pathways triggerring senescence are blocked and cellular immortalization is observed. In contrast, in EC presenting higher levels of damage undergone in vivo, NAC has no effect by itself on the onset of senescence, hTERT delays the onset of senescence in combination or not with NAC, but no cellular immortalization was observed in NAC-hTERT cells. In conclusion, our studies show that a chronic in vivo exposition to oxidative stress associated with risk factors for CVD accelerates the onset of vascular endothelial cells senescence that could potentially contribute to atherogenesis. EC having strong antioxidant defense capacity and DNA repair mechanisms may be rescued from replicative and stress-induced senescence unless EC have undergone an insurmountable cellular and molecular damage possibly due to uncontrolled free radical production associated with risk factors for CVD.
7

Análise comparativa da perviedade das artérias torácicas internas direita e esquerda na revascularização da região anterior do coração. Avaliação por angiotomografia no 6º mês de pós-operatório / Comparative analysis of patency of right and left internal mammary artery in the revascularization of left anterior descending and branches. Evaluation by angiography in the sixth month postoperatively

Maurilio Onofre Deininger 04 October 2012 (has links)
Objetivos: O objetivo deste estudo é analisar a perviedade da artéria torácica interna direita (ATID) pediculada, anteroaórtica em anastomose para a região anterior do coração na cirurgia de revascularização do miocárdio (RM), em relação à artéria torácica interna esquerda (ATIE). Métodos: No período de dezembro de 2008 a dezembro de 2011, 100 pacientes foram selecionados para serem submetidos a cirurgia de RM sem circulação extracorpórea (CEC), de forma prospectiva. Eles foram agrupados em Grupo 1 (G-1) e Grupo 2 (G-2), cada um com 50 pacientes, com randomização por computador e conhecimento da técnica no início da cirurgia. No G-1, os pacientes receberam ATIE para a região anterior do coração e complementação da RM com a ATID livre para ramos da circunflexa (CX) e outros enxertos arteriais ou venosos para a coronária direita (CD) e/ou ramos. Os pacientes do G-2 receberam ATID pediculada para a região anterior do coração e complementação da RM com ATIE, pediculada, para ramos da CX e outros enxertos arteriais ou venosos para a CD e/ou ramos. A perviedade das artérias torácicas internas direita e esquerda foi avaliada através de angiotomografia coronária multislice, 64 canais, no 6º mês de pós-operatório. Resultados: Os dois grupos eram semelhantes quanto aos dados clínicos de pré-operatório, como exemplo: diabetes mellitus, hipertensão arterial sistêmica, obesidade. Os dois grupos apresentaram predominância do sexo masculino com 75,6% e 88% nos grupos 1 e 2, respectivamente. Cinco pacientes migraram do G-1 para o G-2 em virtude de doença ateromatosa na aorta ascendente e um deles foi excluído por ter que utilizar enxerto composto. A média de anastomoses distais no G-1 foi de 3,48 (DP=0,72), e no G-2 foi de 3,20 (DP=0,76). Não ocorreu mediastinite em nenhum paciente. Uma paciente do G-1 apresentou osteomielite, e necessitou de intervenção cirúrgica. Dois pacientes do G-1 foram submetidos a reoperação por sangramento. Os resultados das angiotomografias coronarianas com 96 pacientes re-estudados mostram que todas as ATIs, fosse a direita ou a esquerda, utilizadas pediculadas para a região anterior do coração encontravam-se sem oclusões ou estenoses, configurando 100% de perviedade. No G-1, um enxerto livre da ATID para ramos da CX apresentava oclusão total, em dois pacientes havia estenose leve, em um deles havia estenose moderada na anastomose proximal na aorta ascendente e outro apresentava diminuição de calibre na sua porção distal. Em três pacientes o enxerto de segmento de veia safena para ramos da CD se encontravam ocluídos. No G-2, dois pacientes apresentavam oclusão total na ATIE pediculada para ramos da CX, e outro apresentava estenose moderada na porção distal da ATIE utilizada sequencial para dois ramos marginais. Em dois pacientes o enxerto de segmento de veia safena para ramos da CD se encontravam ocluídos. Não houve óbitos em nenhum dos grupos. Conclusão: A cirurgia de RM com utilização da ATID pediculada, anterógrada para o RIA, apresenta resultado semelhante ao da ATIE utilizada para essa mesma coronária. / Objective: To analyze the patency of the pedicled, anteroaortic, right internal mammary artery (RIMA) anastomosed to the left anterior descending (LAD) and branches in coronary artery bypass graft surgery (CABG), in comparison with the left internal mammary artery (LIMA). Methods: From December 2008 to December 2011, 100 patients were selected to undergo a prospective off-pump coronary artery bypass graft surgery and were randomly divided by computer into Group 1 (G-1) and Group 2 (G-2), so that the technique was known at the beginning of the surgery. In each group, with 50 patients, the patency of both right and left internal mammary arteries, which were used pedicled to the LAD, was comparatively studied through coronary computed tomography angiography. G-1 had 50 patients who received the LIMA to the LAD or LAD/diagonal (sequential) and had the CABG complemented with the free RIMA to circumflex branches and other arterial or venous grafts to the right coronary artery (RCA) and/or branches. G-2 had 50 patients who received the pedicled RIMA to the LAD or LAD/diagonal (sequential) and had the CABG complemented with the pedicled LIMA to circumflex branches and other arterial or venous grafts to the RCA and/or branches. Results: Both groups were similar in pre-operative clinical data, such as: diabetes mellitus, systemic arterial hypertension, obesity. Also, there was predominance of males in both groups, with 75,6% and 88% in Groups 1 and 2 respectively. Five patients were switched from G-1 to G-2 owing to atheromatous disease in the ascending aorta, and one of them was dropped for having to use composite graft. The average of distal anastomosis in G-1 was 3,48 (standard deviation (SD=0,72) and in G-2 was 3,20 (SD=0,76). Mediastinitis didn\'t occur in any patient. A patient from G-1 had osteomyelitis that required surgical intervention. Two patients from G-1 underwent reoperation because of bleeding. The 64-slice coronary computed tomography angiography was performed in the 6th postoperative month; 96 patients have been re-studied so far and all pedicled IMAs to the LAD were patent. In G-1 a free RIMA graft to the circumflex branches presented total occlusion, another two had a discreet stenosis and in one moderate at the proximal anastomosis and one more had a string signal at the distal portion. In G-2 two patients had total occlusion of the pedicled LIMA to circumflex artery branches, and another one presented moderate stenosis at its distal portion. In two patients the saphenous vein graft to the RCA branches were occluded. There were no deaths in any of the groups. Conclusion: The CABG surgery using the pedicled, anteroaortic RIMA to the LAD has a similar outcome to that of the LIMA used for this same coronary.

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