This paper presents a new system for the activity assay of arginine kinase (AK), based on the spectrophotometric determination of an ascorbic acid reduced blue ternary heteropolyacid composed of bismuth, molybdate...This paper presents a new system for the activity assay of arginine kinase (AK), based on the spectrophotometric determination of an ascorbic acid reduced blue ternary heteropolyacid composed of bismuth, molybdate and the released phosphate from N phospho L arginine (PArg) formed in the forward catalysis reaction. The assay conditions, including the formulation of the phosphate determination reagent (PDR), the assay timing, and the linear activity range of the enzyme concentration, have been tested and optimized. For these conditions, the ternary heteropolyacid color is completely developed within 1 min and is stable for at least 15 min, with an absorbance maximum at 700 nm and a molar extinction coefficient of 15.97 (mmol/L) -1 ·cm -1 for the phosphate. Standard curves for phosphate show a good linearity of 0.999. Compared with previous activity assay methods for AK, this system exhibits superior sensitivity, reproducibility, and adaptability to various conditions in enzymological studies. This method also reduces the assay time and avoids the use of some expensive instruments and reagents.展开更多
Objective: To investigate the immunobiological essence of T-activated killer (T-AK) cells induced by anti-CD3 monoclonal antibody (CD3McAb) and recombinant interleukin-2 (rIL-2) co-stimulation. Methods: The cytomorpho...Objective: To investigate the immunobiological essence of T-activated killer (T-AK) cells induced by anti-CD3 monoclonal antibody (CD3McAb) and recombinant interleukin-2 (rIL-2) co-stimulation. Methods: The cytomorphology, phenotype and cytotoxicity of T-AK cells generated from human peripheral blood mononuclear cells (PBMC) were determined. Results: T-AK cells were similar to activated lymphoblasts in morphology, more than 90% of T-AK cells expressed the phenotypes of T-lymphocytes (CD3 +, CD8 +, and 20%～50% of the cells were NK-like phenotype (CD16 +, CD56 +, some of them expressed IL-2 receptor (CD25 +), CD38 antigen (CD38 +) and MHC-II antigen (HLA-DR+) characteristic marks for the activated T lymphocytes. T-AK cells attacking targets were morphologically large volumes with granules and mainly contained CD8 + and CD56 + cells. T-AK cells possessed high tumoricidal activities against NK-sensitive K562 cells and NK-resistant Raji cells, the cytotoxicity was composed of mainly CD3McAb-activated CD3AK activity (～50%), IL-2 induced LAK activity (～30%), NK activity (～10%) and the activities of inhibitory factors in T-AK supernatant (～10%). Conclusion: T-AK cells are a heterogeneous cell population consisting of mainly activated T lymphocytes and NK-like cells, the main part of T-AK cytotoxicity is the common activities of CD3AK cells and LAK cells.展开更多
Key agreement protocols are essential for secure communications. In this paper, to solve the inherent key escrow problem of identity-based cryptography, an escrow-free certificate-based authenticated key agreement （C...Key agreement protocols are essential for secure communications. In this paper, to solve the inherent key escrow problem of identity-based cryptography, an escrow-free certificate-based authenticated key agreement （CB-AK） protocol with perfect forward secrecy is proposed. Our protocol makes use of pairings on elliptic curves. The protocol is described and its properties are discussed though comparison with Smart＇s protocol.展开更多
文摘This paper presents a new system for the activity assay of arginine kinase (AK), based on the spectrophotometric determination of an ascorbic acid reduced blue ternary heteropolyacid composed of bismuth, molybdate and the released phosphate from N phospho L arginine (PArg) formed in the forward catalysis reaction. The assay conditions, including the formulation of the phosphate determination reagent (PDR), the assay timing, and the linear activity range of the enzyme concentration, have been tested and optimized. For these conditions, the ternary heteropolyacid color is completely developed within 1 min and is stable for at least 15 min, with an absorbance maximum at 700 nm and a molar extinction coefficient of 15.97 (mmol/L) -1 ·cm -1 for the phosphate. Standard curves for phosphate show a good linearity of 0.999. Compared with previous activity assay methods for AK, this system exhibits superior sensitivity, reproducibility, and adaptability to various conditions in enzymological studies. This method also reduces the assay time and avoids the use of some expensive instruments and reagents.
文摘Objective: To investigate the immunobiological essence of T-activated killer (T-AK) cells induced by anti-CD3 monoclonal antibody (CD3McAb) and recombinant interleukin-2 (rIL-2) co-stimulation. Methods: The cytomorphology, phenotype and cytotoxicity of T-AK cells generated from human peripheral blood mononuclear cells (PBMC) were determined. Results: T-AK cells were similar to activated lymphoblasts in morphology, more than 90% of T-AK cells expressed the phenotypes of T-lymphocytes (CD3 +, CD8 +, and 20%～50% of the cells were NK-like phenotype (CD16 +, CD56 +, some of them expressed IL-2 receptor (CD25 +), CD38 antigen (CD38 +) and MHC-II antigen (HLA-DR+) characteristic marks for the activated T lymphocytes. T-AK cells attacking targets were morphologically large volumes with granules and mainly contained CD8 + and CD56 + cells. T-AK cells possessed high tumoricidal activities against NK-sensitive K562 cells and NK-resistant Raji cells, the cytotoxicity was composed of mainly CD3McAb-activated CD3AK activity (～50%), IL-2 induced LAK activity (～30%), NK activity (～10%) and the activities of inhibitory factors in T-AK supernatant (～10%). Conclusion: T-AK cells are a heterogeneous cell population consisting of mainly activated T lymphocytes and NK-like cells, the main part of T-AK cytotoxicity is the common activities of CD3AK cells and LAK cells.
基金Supported by the National Natural Science Founda-tion of China (60225007, 60572155) and the Science and Technology Research Project of Shanghai (04DZ07067)
文摘Key agreement protocols are essential for secure communications. In this paper, to solve the inherent key escrow problem of identity-based cryptography, an escrow-free certificate-based authenticated key agreement （CB-AK） protocol with perfect forward secrecy is proposed. Our protocol makes use of pairings on elliptic curves. The protocol is described and its properties are discussed though comparison with Smart＇s protocol.
