The geometry of unstented and stented pig common carotid artery bypass grafts

The long-term success of arterial bypass grafting with autologous saphenous veins is limited by neointimal hyperplasia (NIH), which seemingly develops preferentially at sites where hydrodynamic wall shear is low. Placement of a loose-fitting, porous stent around end-to-end, or end-to-side, autologous saphenous vein grafts on the porcine common carotid artery has been found significantly to reduce NIH, but the mechanism is unclear. In a preliminary study, we implanted autologous saphenous vein grafts bilaterally on the common carotid arteries of pigs, placing a stent around one graft and leaving the contralateral graft unstented. At sacrifice 1 month post implantation, the grafts were pressure fixed in situ and resin casts were made. Unstented graft geometry was highly irregular, with non-uniform dilatation, substantial axial lengthening, curvature, kinking, and possible long-pitch helical distortion. In contrast, stented grafts showed no major dilatation, lengthening or curvature, but there was commonly fine corrugation, occasional slight kinking or narrowing of segments, and possible long-pitch helical distortion. Axial growth of grafts against effectively tethered anastomoses could account for these changes. CFD studies are planned, using 3D MR reconstructions, on the effects of graft geometry on the flow. Abnormality of the flow could favour the development of vascular pathology, including NIH.

Genome wide interactions of wild-type and activator bypass forms of σ54

Enhancer-dependent transcription involving the promoter specificity factor σ54 is widely distributed amongst bacteria and commonly associated with cell envelope function. For transcription initiation, σ54-RNA polymerase yields open promoter complexes through its remodelling by cognate AAA+ ATPase activators. Since activators can be bypassed in vitro, bypass transcription in vivo could be a source of emergent gene expression along evolutionary pathways yielding new control networks and transcription patterns. At a single test promoter in vivo bypass transcription was not observed. We now use genome-wide transcription profiling, genome-wide mutagenesis and gene over-expression strategies in Escherichia coli, to (i) scope the range of bypass transcription in vivo and (ii) identify genes which might alter bypass transcription in vivo. We find little evidence for pervasive bypass transcription in vivo with only a small subset of σ54 promoters functioning without activators. Results also suggest no one gene limits bypass transcription in vivo, arguing bypass transcription is strongly kept in check. Promoter sequences subject to repression by σ54 were evident, indicating loss of rpoN (encoding σ54) rather than creating rpoN bypass alleles would be one evolutionary route for new gene expression patterns. Finally, cold-shock promoters showed unusual σ54-dependence in vivo not readily correlated with conventional σ54 binding-sites.

Estudo de metodologias de caracterização de sinais de fluxo sanguíneo em bypass cardíacos

O processamento de sinais de fluxo sanguíneo tem sido objecto de interesse de muitos investigadores, no entanto até este momento, tanto quanto se sabe, não existe caracterização de sinais de ultra-som Doppler de fluxo sanguíneo em vasos cardíacos com inserção de bypass. A presente dissertação, inserida nos objectivos de um projecto de investigação internacional, apresenta as metodologias desenvolvidas com vista à tipificação de sinais ultra-sónicos de fluxo sanguíneo recolhidos em bypass cardíacos e à verificação da variabilidade da composição do sangue artificial com a temperatura ambiente e com a utilização de diferentes marcas dos seus compostos. No que concerne à composição do sangue artificial verifica-se que a utilização de detergentes de marcas diferentes não influencia o espectrograma dos sinais ultra-sónicos; contudo, o glicerol brasileiro possibilita melhor dispersão das partículas de PVC que o glicerol português. Verifica-se também que o aumento da temperatura a que o sangue artificial e o ambiente envolvente se encontram potencia claramente a identificação das envolventes do espectrograma correspondente. Os sinais ultra-sónicos de fluxo sanguíneo foram distinguidos em siglas FL, FR e FT e foram pré-processados removendo-se o ruído de baixas frequências (até 430Hz) e as baixas intensidades de potência (inferiores a um limiar de 35). Após a determinação da envolvente dos ciclos cardíacos, foi calculado o ciclo cardíaco médio de cada sigla. Analisando as características dos ciclos cardíacos médios: tempos de subida e descida do pico máximo, tempo acima da média do ciclo cardíaco médio, índice de pulsatilidade, frequências máxima e média e ainda a duração temporal, conseguiu identificar-se que os sinais FT apresentam durações temporais maiores e um espectrograma maioritariamente acima da frequência média do ciclo cardíaco, os sinais FR apresentam maior índice de pulsatilidade e maiores valores de frequência máxima. Os sinais FL apresentam características intermédias.

Ultra compact pseudo-elliptic inline waveguide bandpass filters using bypass coupling

This paper presents an ultra compact waveguide bandpass filter that exhibits a pseudo-elliptic response. The transmission zero created in the upper stopband to form a rapid roll off is produced through a bypass coupling with higher order modes. A 3rd order filter is designed at the centre frequency of 9.4 GHz with a 5.3% fractional bandwidth. The proposed structure's size is 38% smaller than one of a 3rd order E-plane extracted pole filter with comparable response. Additionally, this configuration allows larger span of different bandwidths. The filter has been fabricated and tested using E-plane waveguide technology, which has benefits of being inexpensive and having mass producible capabilities. Measurements of such a fabricated filter validate the simulated results.

Anthropometric evaluation and micronutrients intake in patients submitted to laparoscopic Roux-en-Y gastric bypass with a postoperative period of ≥1 year

Backgroung - Bariatric surgery is indicated as the most effective treatment for morbid obesity; the Roux-en-Y gastric bypass (RYGB) is considered the procedure of choice. However, nutritional deficiency may occur in the postoperative period as a result of reduced gastric capacity and change in nutrients absorption in the gastrointestinal tract. The prescription of vitamin and mineral supplementation is a common practice after RYGB; however, it may not be sufficient to prevent micronutrient deficiencies. The aim of this study was to quantify the micronutrient intake in patients undergoing RYGB and verify if the intake of supplementation would be enough to prevent nutritional deficiencies. Methods - The study was conducted on 60 patients submitted to RYGB. Anthropometric, analytical, and nutritional intake data were assessed preoperatively and 1 and 2 years postoperatively. The dietary intake was assessed using 24-h food recall; the values of micronutrients evaluated (vitamin B12, folic acid, iron, and calcium) were compared to the dietary reference intakes (DRI). Results - There were significant differences (p < 0.05) between excess weight loss at the first and second year (69.9 ± 15.3 vs 9.6 ± 62.9 %). In the first and second year after surgery, 93.3 and 94.1 % of the patients, respectively, took the supplements as prescribed. Micronutrient deficiencies were detected in the three evaluation periods. At the first year, there was a significant reduction (p < 0.05) of B12, folic acid, and iron intake. Conclusions - Despite taking vitamin and mineral supplementation, micronutrient deficiencies are common after RYGB. In the second year after surgery, micronutrient intake remains below the DRI.

Aneurysms of saphenous vein grafts as late complication of coronary artery bypass surgery: successful exclusion by percutaneous transcatheter embolization.

We report a case of a 71-year-old man with a long coronary artery disease history and two sets of coronary artery bypass grafts. He developed large aortocoronary saphenous vein graft aneurysms in the two grafts from the first set of aortocoronary saphenous venous 20 years later. During the previous 3 years, the aneurysms grew in diameter from 22 to 50 mm. Because of severe renal insufficiency, and in order to avoid jeopardizing the late normal coronary artery bypass grafts by further thoracic surgery, we excluded successfully these altered grafts percutaneously by using 13 coils during the same procedure.

Impaired left ventricular function as a predictive factor for mid-term survival in octogenarians after primary coronary artery bypass surgery.

BACKGROUND: The impact of preoperative impaired left ventricular ejection fraction (EF) in octogenarians following coronary bypass surgery on short-term survival was evaluated in this study. METHODS: A total of 147 octogenarians (mean age 82.1 ± 1.9 years) with coronary artery diseases underwent elective coronary artery bypass graft between January 2000 and December 2009. Patients were stratified into: Group I (n = 59) with EF >50%, Group II (n = 59) with 50% > EF >30% and in Group III (n = 29) with 30% > EF. RESULTS: There was no difference among the three groups regarding incidence of COPD, renal failure, congestive heart failure, diabetes, and preoperative cerebrovascular events. Postoperative atrial fibrillation was the sole independent predictive factor for in-hospital mortality (odds ratio (OR), 18.1); this was 8.5% in Group I, 15.3% in Group II and 10.3% in Group III. Independent predictive factors for mortality during follow up were: decrease of EF during follow-up for more that 5% (OR, 5.2), usage of left internal mammary artery as free graft (OR, 18.1), and EF in follow-up lower than 40% (OR, 4.8). CONCLUSIONS: The results herein suggest acceptable in-hospital as well short-term mortality in octogenarians with impaired EF following coronary artery bypass grafting (CABG) and are comparable to recent literature where the mortality of younger patients was up to 15% and short-term mortality up to 40%, respectively. Accordingly, we can also state that in an octogenarian cohort with impaired EF, CABG is a viable treatment with acceptable mortality.

Modifiable and nonmodifiable risk factors for postoperative delirium after cardiac surgery with cardiopulmonary bypass.

Postoperative delirium after cardiac surgery is associated with increased morbidity and mortality as well as prolonged stay in both the intensive care unit and the hospital. The authors sought to identify modifiable risk factors associated with the development of postoperative delirium in elderly patients after elective cardiac surgery in order to be able to design follow-up studies aimed at the prevention of delirium by optimizing perioperative management. A post hoc analysis of data from patients enrolled in a randomized controlled trial was performed. A single university hospital. One hundred thirteen patients aged 65 or older undergoing elective cardiac surgery with cardiopulmonary bypass. None. MEASUREMENTS AND MAINS RESULTS: Screening for delirium was performed using the Confusion Assessment Method (CAM) on the first 6 postoperative days. A multivariable logistic regression model was developed to identify significant risk factors and to control for confounders. Delirium developed in 35 of 113 patients (30%). The multivariable model showed the maximum value of C-reactive protein measured postoperatively, the dose of fentanyl per kilogram of body weight administered intraoperatively, and the duration of mechanical ventilation to be independently associated with delirium. In this post hoc analysis, larger doses of fentanyl administered intraoperatively and longer duration of mechanical ventilation were associated with postoperative delirium in the elderly after cardiac surgery. Prospective randomized trials should be performed to test the hypotheses that a reduced dose of fentanyl administered intraoperatively, the use of a different opioid, or weaning protocols aimed at early extubation prevent delirium in these patients.

Intraoperative hemodynamic instability during and after separation from cardiopulmonary bypass : importance, mechanism and prevention

Chaque année, environ 1 à 1,25 million d’individus subiront une chirurgie cardiaque. [1] Environ 36 000 chirurgies cardiaques sont effectuées au Canada et 8000 procédures au Québec (http://www.ccs.ca). Le vieillissement de la population aura pour conséquence que la chirurgie cardiaque sera offerte à des patients de plus en plus à risque de complications, principalement en raison d’une co-morbidité plus importante, d’un risque de maladie coronarienne plus élevée, [2] d’une réserve physiologique réduite et par conséquent un risque plus élevé de mortalité à la suite d’une chirurgie cardiaque. L’une des complications significatives à la suite d’une chirurgie cardiaque est le sevrage difficile de la circulation extracorporelle. Ce dernier inclut la période au début du sevrage de la circulation extracorporelle et s’étend jusqu’au départ du patient de la salle d’opération. Lorsque le sevrage de la circulation extracorporelle est associé à une défaillance ventriculaire droite, la mortalité sera de 44 % à 86 %. [3-7] Par conséquent le diagnostic, l’identification des facteurs de risque, la compréhension du mécanisme, la prévention et le traitement du sevrage difficile de la circulation extracorporelle seront d’une importance majeure dans la sélection et la prise en charge des patients devant subir une chirurgie cardiaque. Les hypothèses de cette thèse sont les suivantes : 1) le sevrage difficile de la circulation extracorporelle est un facteur indépendant de mortalité et de morbidité, 2) le mécanisme du sevrage difficile de la circulation extracorporelle peut être approché d’une façon systématique, 3) la milrinone administrée par inhalation représente une alternative préventive et thérapeutique chez le patient à risque d’un sevrage difficile de la circulation extracorporelle après la chirurgie cardiaque.

The effects of administration of a nuclear factor kappa-B inhibitor on pulmonary endothelial dysfunction after cardiopulmonary bypass: impact on oxygenation and hemodynamics and development of therapeutic and preventive modalities in a porcine model

Introduction: La circulation extracorporelle (CEC) peut entraîner une dysfonction endothéliale pulmonaire et l’hypertension pulmonaire. Le SN50 agit au niveau de la signalisation cellulaire pour prévenir ces réactions à la CEC et pourrait renverser la dysfonction endothéliale pulmonaire post-CEC sans effets néfastes sur l’hémodynamie. Méthodes: Quatre groups de porcs ont reçu un parmi quatre traîtements avant de subir 90 minutes de CEC et 60 minutes de reperfusion: (1) milrinone nébulisé; (2) sildenafil nébulisé; (3) placebo nébulisé; et (4) SN-50 intraveineux. Un monitoring hémodynamique invasif a été utilisé. La réactivité vasculaire des artères pulmonaires de deuxième ordre a été évaluée face à l’acétylcholine et la bradykinine. Résultats: Le sildénafil produit une augmentation significative de la pression de l’artère pulmonaire (PAP) moyenne à 60 minutes de reperfusion par rapport au début de la chirurgie. Les relaxations dépendantes de l’endothélium face à la bradykinine étaient meilleurs dans les groupes milrinone et SN-50 et surtout dans le groupe sildénafil par rapport au groupe placébo. Le SN-50 produisait de moins bonnes relaxations dépendantes de l’endothélium face à l’acétylcholine que les autres traitements incluant placébo. Conclusion: Le sildénafil prévient mieux la dysfonction endothéliale pulmonaire que les autres traitements. Les bénéfices du SN-50 sont possiblement sous-estimés vu que la dose n’a pas pu être ajustée à la durée de CEC. Le sildenafil inhalé mérite une étude plus importante chez l’humain et le SN-50 dans un model de CEC animal.

Cáncer gástrico en Colombia entre 2000 y 2009

Introducción: De todos los casos de cáncer en el mundo el 80% se presentan en países en vía de desarrollo siendo el cáncer de estómago o cáncer gástrico la segunda causa de muerte por cáncer en el mundo con aproximadamente 700.000 muertes cada año. En Colombia, el cáncer gástrico es la primera causa de muerte por tumores malignos en ambos sexos, aún cuando no es la primera neoplasia en frecuencia. Metodología: Estudio observacional descriptivo, de registros de defunción del DANE, Colombia 2000 a 2009. Se analizaron tasas anuales crudas y por grupos de edad, género, procedencia geográfica, estado civil, nivel educativo y área de residencia habitual estableciendo diferencias estadísticas entre las variables y sus categorías. Resultados: En el período estudiado se registraron 43759 defunciones por cáncer gástrico, con mayor frecuencia en hombres 1,5:1. Las tasas de mortalidad por cáncer gástrico ajustadas por grupos etáreos aumentan después de la quinta década de la vida. Se encontraron diferencias estadísticamente significativas en todos los años estudiados y el departamento de residencia habitual del fallecido presentando Cauca (18,11- 19) y Boyacá (14,54-1742) las tasas más altas por 100.000 habitantes. Las tasas más altas se concentran en la zona de la Cordillera de los Andes, al estandarizar por grupos etáreos el Cauca tiene una tasa de 114,98 casos por 100.000 habitantes. Conclusión: El cáncer gástrico es la neoplasia que causa más muertes en Colombia por lo cual es necesario diseñar e implementar programas de detección precoz que vayan dirigidos al control de la mortalidad.

Ideación suicida y algunos factores biopsicosociales asociados con estas en pacientes adultos con leucemia, linfomas, cáncer gástrico o cáncer colorrectal Informe de investigación

El cáncer es una de las enfermedades con mayor impacto en la población mundial, debido a que genera alteraciones en las áreas de ajuste de los individuos, su núcleo familiar y social circundante. El presente estudio tiene como objetivo establecer la prevalencia de ideación suicida en pacientes con cáncer de tejidos blandos (leucemias y linfomas) y cáncer gástrico (colorectal). Fue un estudio exploratorio descriptivo, de la línea de investigación en Psicooncología y Cuidado Paliativo a la cual pertenece el proyecto: “Conducta suicida (ideación suicida, intención suicida y suicidio frustrado) y factores biopsicosociales asociadas a esta en pacientes con cáncer”. La población que participó en este estudio fueron pacientes adultos del Centro de Investigaciones oncológicas de la clínica San Diego CIOSAD. De esta investigación se puede concluir que la prevalencia de ideación suicida en pacientes con estos tipos de cáncer es de 4.9% (N=10). Los factores asociados a la ideación suicida fueron: número de hijos, dolor y ansiedad en la última semana y estrato socioeconómico

Alteración en la regulación de la apoptosis vía Fas/FasL en cáncer gástrico

El cáncer gástrico es una de las enfermedades neoplásicas de más alta incidencia y mortalidad a nivel mundial: es el segundo tipo de cáncer más frecuente en el mundo y la primera causa mundial de mortalidad por esta enfermedad. Por su parte, la apoptosis es un proceso importante de muerte celular programada que se presenta durante la embriogénesis, la regulación del sistema inmune y el mantenimiento de la homeostasis tisular. La evasión de la apoptosis por diferentes mecanismos es uno de los aspectos moleculares más importantes en el desarrollo de cáncer. En este artículo se presenta una revisión exhaustiva de la evidencia del papel de la apoptosis vía Fas/FasL en el desarrollo de la carcinogénesis gástrica, inclusive desde etapas tempranas, como la aparición de lesiones preneoplásicas. Finalmente, se evidencia que el desarrollo de más estudios permitiría esclarecer mejor el papel de la vía Fas/FasL en la carcinogénesis gástrica, en sus diferentes estadios.

Vuxna personers upplevelse av hälsorelaterad livskvalité efter en gastric bypass operation : –En litteraturöversikt

Bakgrund: Fetma och övervikt har blivit vanligare den senaste tiden och är idag ett stort hälsoproblem över hela världen. Många har svårt att gå ner i vikt på egen hand vilket har gjort att kirurgi har blivit allt vanligare de senaste åren. Gastric bypass är idag den vanligaste kirurgiska metoden för viktminskning och har visat goda resultat. Däremot kan den hälsorelaterade livskvalitén påverkas då operationen innebär en stor livsstilsförändring. Syfte: Syftet med denna studie var att beskriva vuxna personers upplevelse av hälsorelaterad livskvalité efter en gastric bypass operation. Metod: En litteraturöversikt med 11 kvantitativa och 3 kvalitativa vetenskapliga artiklar som ligger till grund för hur vuxna personer upplever sin hälsorelaterade livskvalité efter en gastric bypass operation. Resultat: Hälsorelaterad livskvalité (HRQOL) har visat en förbättring i samtliga studier efter en gastric bypass operation. HRQOL har haft sin topp efter 1 månad i samtliga skalor utifrån SF-36 frågeformulär. Slutsats: Den stora livsstilsförändringen som personer går igenom efter en gastric bypass operationen har visat förbättringar i HRQOL på både lång och kort sikt. Bidragande faktorer som kan påverka den förbättrade hälsorelaterade livskvalitén kan bland annat vara uppfyllda förväntningar av operationen och fysisk aktivitet.