Evaluación de la actividad enzimática de la lacasa recombinante poxa 1b expresada en Pichia pastoris usando residuos de crisantemo

Colombia es uno de los principales exportadores de flores al mundo, entre las que se encuentra el crisantemo. Los residuos generados durante su producción, generan un impacto ambiental negativo. Razón por la cual este trabajo de grado tuvo como objetivo evaluar la actividad enzimática de la lacasa recombinante POXA 1B expresada en Pichia pastoris usando residuos de crisantemo. Se realizó un estudio preliminar del cual se decidió que no se era necesario el agregar CuSO4 como cofactor de la actividad enzimática, cuando el residuo se encontraba presente. De acuerdo a esto, se planteó un diseño factorial, en el que se evaluó la concentración de glucosa, fuente de nitrógeno, porcentaje de inoculo y tiempo de cultivo. Como consecuencia de esto se obtuvieron los mejores resultados para la actividad enzimática, en la combinación con una concentración de glucosa 3% (p/v), nitrógeno (extracto levadura - peptona 1% (p/v)), concentración de inóculo 10% (v/v) y 168 h, con 2074 U/L de lacasa. Se analizó la productividad (actividad enzimática) y rendimiento producto a partir de sustrato (Yp/s) (glucosa) de los que obtuvieron que con la concentración de glucosa 3%, nitrógeno (extracto levadura -peptona 1%), concentración de inóculo 12% y 72 h de cultivo con una productividad del 21,4 UL-1h-1. Y con la concentración de glucosa 1%, nitrógeno (extracto levadura 1% -peptona 2%), concentración de inóculo 10% y 72 h, con un rendimiento del 81,913 U/g. Para complementar esto se verifico la técnica para la determinación del porcentaje de lignina presente en una muestra vegetal.Colombia is one of the Major exporters of flowers to the world, among which is the chrysanthemum. The waste generated during production, generate a negative environmental impact. For that reason degree work was to evaluate enzymatic activity of the recombinant laccase POXA 1B expressed in Pichia pastoris using waste chrysanthemum. In a preliminary study was made, after that decided that was not necessary add CuSO4 as a cofactor in enzyme activity when the residue was present. Accordingly, it posed a factorial design, in which the concentration of glucose, nitrogen source, percentage of inoculum and culture time were evaluated. As a result obtained the best results for enzyme activity, in combination with a glucose concentration of 3% (w/v), nitrogen (yeast extract - peptone 1% (w/v)), inoculum concentration 10% (v/v) and 168h, with 2,074 U/L of laccase. The productivity (enzymatic activity) and yield product from a substrate (Yp/s) (glucose) from which they obtained was analyzed than with a glucose concentration of 3% nitrogen (1% yeast extract -peptone), inoculum concentration 12 % to 72 h of culture with a productivity of 21.4 UL-1h-1. And with the concentration of glucose 1%, nitrogen (1% yeast extract -peptone 2%), inoculum concentration 10% to 72 h, with a yield of 81 913 U / g. To complement this was verified the technique for determining the percentage of lignin present in a plant sample.Microbiólogo (a) IndustrialPregrad

Stoma-free survival after anastomotic leak following rectal cancer resection: worldwide cohort of 2470 patients

Background: The optimal treatment of anastomotic leak after rectal cancer resection is unclear. This worldwide cohort study aimed to provide an overview of four treatment strategies applied. Methods: Patients from 216 centres and 45 countries with anastomotic leak after rectal cancer resection between 2014 and 2018 were included. Treatment was categorized as salvage surgery, faecal diversion with passive or active (vacuum) drainage, and no primary/secondary faecal diversion. The primary outcome was 1-year stoma-free survival. In addition, passive and active drainage were compared using propensity score matching (2: 1). Results: Of 2470 evaluable patients, 388 (16.0 per cent) underwent salvage surgery, 1524 (62.0 per cent) passive drainage, 278 (11.0 per cent) active drainage, and 280 (11.0 per cent) had no faecal diversion. One-year stoma-free survival rates were 13.7, 48.3, 48.2, and 65.4 per cent respectively. Propensity score matching resulted in 556 patients with passive and 278 with active drainage. There was no statistically significant difference between these groups in 1-year stoma-free survival (OR 0.95, 95 per cent c.i. 0.66 to 1.33), with a risk difference of -1.1 (95 per cent c.i. -9.0 to 7.0) per cent. After active drainage, more patients required secondary salvage surgery (OR 2.32, 1.49 to 3.59), prolonged hospital admission (an additional 6 (95 per cent c.i. 2 to 10) days), and ICU admission (OR 1.41, 1.02 to 1.94). Mean duration of leak healing did not differ significantly (an additional 12 (-28 to 52) days). Conclusion: Primary salvage surgery or omission of faecal diversion likely correspond to the most severe and least severe leaks respectively. In patients with diverted leaks, stoma-free survival did not differ statistically between passive and active drainage, although the increased risk of secondary salvage surgery and ICU admission suggests residual confounding

Stoma-free Survival After Rectal Cancer Resection With Anastomotic Leakage: Development and Validation of a Prediction Model in a Large International Cohort.

Objective:To develop and validate a prediction model (STOMA score) for 1-year stoma-free survival in patients with rectal cancer (RC) with anastomotic leakage (AL).Background:AL after RC resection often results in a permanent stoma.Methods:This international retrospective cohort study (TENTACLE-Rectum) encompassed 216 participating centres and included patients who developed AL after RC surgery between 2014 and 2018. Clinically relevant predictors for 1-year stoma-free survival were included in uni and multivariable logistic regression models. The STOMA score was developed and internally validated in a cohort of patients operated between 2014 and 2017, with subsequent temporal validation in a 2018 cohort. The discriminative power and calibration of the models' performance were evaluated.Results:This study included 2499 patients with AL, 1954 in the development cohort and 545 in the validation cohort. Baseline characteristics were comparable. One-year stoma-free survival was 45.0% in the development cohort and 43.7% in the validation cohort. The following predictors were included in the STOMA score: sex, age, American Society of Anestesiologist classification, body mass index, clinical M-disease, neoadjuvant therapy, abdominal and transanal approach, primary defunctioning stoma, multivisceral resection, clinical setting in which AL was diagnosed, postoperative day of AL diagnosis, abdominal contamination, anastomotic defect circumference, bowel wall ischemia, anastomotic fistula, retraction, and reactivation leakage. The STOMA score showed good discrimination and calibration (c-index: 0.71, 95% CI: 0.66-0.76).Conclusions:The STOMA score consists of 18 clinically relevant factors and estimates the individual risk for 1-year stoma-free survival in patients with AL after RC surgery, which may improve patient counseling and give guidance when analyzing the efficacy of different treatment strategies in future studies