Preparation and evaluation of 186/188Re-labeled antibody (A7) for radioimmunotherapy with rhenium(I) tricarbonyl core as a chelate site

Objective: Rhenium is one of the most valuable elements for internal radiotherapy because 186Re and 188Re have favorable physical characteristics. However, there are problems when proteins such as antibodies are used as carriers of 186/188Re. Labeling methods that use bifunctional chelating agents such as MAG3 require the conjugation of the 186/188Re complex to protein after radiolabeling with the bifunctional chelating agent. These processes are complicated. Therefore, we planned the preparation by a simple method and evaluation of a stable 186/188Re-labeled antibody. For this purpose, we selected 186/188Re(I) tricarbonyl complex as a chelating site. In this study, A7 (an IgG1 murine monoclonal antibody) was used as a model protein. 186/188Re-labeled A7 was prepared by directly reacting a 186/188Re(I) tricarbonyl precursor, [186/188Re(CO)3(H2O)3]+, with A7. We then compared the biodistribution of 186/188Re-labeled A7 in tumor-bearing mice with 125I-labeled A7. Methods: For labeling A7, [186/188Re(CO)3(H2O)3]+ was prepared according to a published procedure. 186/188Re-labeled A7 (186/188Re-(CO)3-A7) was prepared by reacting [186/188Re(CO)3(H2O)3]+ with A7 at 43°C for 2 h. Biodistribution experiments were performed by the intravenous administration of 186/188Re-(CO)3-A7 solution into tumor-bearing mice. Results: 186Re-(CO)3-A7 and 188Re-(CO)3-A7 were prepared with radiochemical yields of 23 and 28%, respectively. After purification with a PD-10 column, 186/188Re-(CO)3-A7 showed a radiochemical purity of over 95%. In biodistribution experiments, 13.1 and 13.2% of the injected dose/g of 186Re-(CO)3-A7 and 188Re-(CO)3-A7, respectively, accumulated in the tumor at 24-h postinjection, and the tumor-to-blood ratios were over 2.0 at the same time point. Meanwhile, uptake of 125I-A7 in the tumor was almost the same as that of 186/188Re-(CO)3-A7 at 24-h postinjection. Blood clearances of 186/188Re-(CO)3-A7 were faster than those of 125I-A7. Conclusion: 186/188Re-labeled A7 showed high uptakes in the tumor. However, further modification of the labeling method would be necessary to improve radiochemical yields and their biodistribution. © 2009 The Japanese Society of Nuclear Medicine

Fast WDM provisioning with minimal probing: the first field experiments for DC exchanges

We propose an approach to estimate the end-to-end GSNR accurately in a short time when a data center interconnect (DCI) network operator receives a service request from users, not by measuring the GSNR at the operational route and wavelength for the End-End optical path but by simply applying a QoT probe channel link by link, at a convenient wavelength/modulation-format for measurement. Assuming connections between coherent transceivers of various frequency ranges, modulators, and modulation formats, we propose a new device software architecture in which the DCI network operator optimizes the transmission mode between user transceivers with high accuracy using only standard parameters such as Bit Error Rate. In this paper, we first experimentally built three different routes of 32 km/72 km/122 km in the C-band to confirm the accuracy of this approach. For the operational end-to-end GSNR measurements, the accuracy estimated from the sum of the measurements for each link was 0.6 dB, and the wavelength-dependent error was about 0.2 dB. Then, using field fibers deployed in the NSF COSMOS testbed (deployed in an urban area), a Linux-based transmission device software architecture, and coherent transceivers with different optical frequency ranges, modulators, and modulation formats, the fast WDM provisioning of an optical path was completed within 6 minutes (with a Q-factor error of about 0.7 dB).Comment: 9 pages, 11 figures, 3 table

Telecom value chain dynamics and carriers' strategies in converged networks

Thesis (S.M.M.O.T.)--Massachusetts Institute of Technology, Sloan School of Management, Management of Technology Program, 2002.Includes bibliographical references (leaves 101-104).This thesis predicts the dynamics of value chains in the telecommunication industry and proposes telecommunication carriers' strategies in future converged networks. It predicts that large carriers will vertically integrate chains for the supply and management of network services. This will dis-integrate network service providers into back-end network providers and front-end service providers, pushing niche network service providers to outsource network operations from large carriers. Building on these forecasts, the thesis proposes the following strategies: First, carriers should do business as both front-end service providers and back-end network providers. Second, as a front-end service provider's strategy, carriers should reinforce their base of loyal customers by providing tailored supply and management services like "Dell Premier". Third, as a back-end network provider's strategy, carriers should create the value of a back-end network like "VISA", by providing services for the inter operation between front-end service providers. Fourth, carriers should also build complementary assets, such as "design-for-manageability" know-how/patents and the position to aggregate contents/applications/ ASPs, taking advantage of their operation volume in back-end network services.by Masahisa Kawashima.S.M.M.O.T