Determinação do teor de ésteres graxos em biodiesel metílico de soja por cromatografia gasosa utilizando oleato de etila como padrão interno

A method for ester content determination in soybean methyl biodiesel was studied, using ethyl oleate as internal standard. A biodiesel sample was analyzed and had its purity estimated as 92.8%. Method accuracy was evaluated by comparison with the result obtained via EN14103, with a relative difference of 0.1%. Repetitivity and intermediate precision were estimated as 2 and 1.5%, respectively

Sulfonamides quantification in milk by high performace liquid chromatography via azoderivatives

O objetivo deste trabalho foi avaliar uma alternativa para a quantificação simultânea de sulfatiazol, sulfametazina e sulfadimetoxina no leite, na forma de azoderivados, por meio de cromatografia líquida de alta eficiência (CLAE). O isolamento e concentração das sulfas foram conduzidos por extração em fase sólida (C18), com metanol como eluente. Após a extração, os analitos foram transformados em sais de diazônio e submetidos ao acoplamento com resorcinol. Os derivados foram separados e quantificados por CLAE (coluna C8, l = 430 nm, MeOH/KH2PO4 aq.). Foram obtidas recuperações entre 65 e 78%.The objective of this work was to evaluate an analytical method for the simultaneous measurement of sulfathiazole, sulfamethazine, and sulfadimethoxine in milk, in the form of azoderivatives, through the high performance liquid chromatography (HPLC). The isolation and concentration of sulfas were carried out by solid phase extraction (C18) with methanol as eluent. After extraction, analytes were transformed in diazonium salts and coupled with resorcinol. Derivatives were quantified by HPLC (C8 column, l = 430 nm, MeOH/KH2PO4 aq). Recoveries were obtained between 65 and 78%

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

Quantificação de sulfadimetoxina em leite por cromatografia líquida de alta eficiência

A method for HPLC determination of sulfadimethoxyne in milk is presented. The analyte isolation and concentration were performed by solid-phase extraction through a C-8 cartridge, pre-conditioned with hexane, methanol and water and eluted with MeOH. The recovery determination was done with a spiked solution of 20, 50 or 100 µg L-1. In this concentration range, the recovery was 83.2% with a RDS of 15.4%. For quantification, a Zorbax Eclipse XDB-C8 (4.6 mm x 150 mm, 5 µm), a mobile phase of MeCN: 0.01 mol L-1 KH2PO4 aq. (1:4), and a variable wavelength detector (275 nm) were used