Preparation of a novel targeted MR contrast agent Gd-DTPA-Granzyme B monoclonal antibody / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To prepare a novel MRI targeted contrast agent Gd-DTPA-Granzyme B monoclonal antibody (mAb) and to test its reaction conditions.</p><p><b>METHODS</b>The Granzyme B mAb was coupled with DTPA,and then conjugated with Gd. The Gd-DTPA antibody was characterized using MALDI-TOF-MS. Cytotoxicity test was performed with MTT assay, and immune activation was examined with immunohistochemistry.</p><p><b>RESULT</b>MALDI-TOF-MS demonstrated that the molecular weight shifted from granzyme B mAb (133986) to Gd-DTPA-GB mAb (139736), which indicated the conjugation of the antibody with Gd-DTPA. The molar ratio of Gd per IgG molecule was about 20. MTT assay showed that Gd, DTPA, Gd-DTPA and Gd-DTPA-GB mAb groups did not make an impact on cell viability, and there were no significant differences among 4 groups (P>0.05). Immunohistochemistry results showed that compared with the positive control group the targeted contrast agent had a high immune activity.</p><p><b>CONCLUSION</b>The novel contrast agent Gd-DTPA-Granzyme B mAb prepared in this study keeps a good immune activity and has no significant cytotoxicity.</p>

Changes of sphingolipids profiles after ischemia-reperfusion injury in the rat liver / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Hepatic ischemia-reperfusion (I/R) injury occurs in many clinical procedures. The molecular mechanisms responsible for hepatic I/R injury however remain unknown. Sphingolipids, in particular ceramide, play a role in stress and death receptor-induced hepatocellular death, contributing to the progression of several liver diseases including liver I/R injury. In order to further define the role of sphingolipids in hepatic I/R, systemic analysis of sphingolipids after reperfusion is necessary.</p><p><b>METHODS</b>We investigated the lipidomic changes of sphingolipids in a rat model of warm hepatic I/R injury, by delayed extraction matrix-assisted laser desorption ionization time-of-flight mass spectrometry (DE MALDI-TOF-MS).</p><p><b>RESULTS</b>The total amounts of ceramide and sphingomyelin and the intensity of most kinds of sphingolipids, mainly sphingomyelin, significantly increased at 1 hour after reperfusion (P < 0.05) and reached peaks at 6 hours after reperfusion (P < 0.01) compared to controls. Six new forms of ceramide and sphingomyelins appeared 6 hours after reperfusion, they were (m/z) 537.8, 555.7, 567.7, 583.8, 683.5 and 731.4 respectively. A ceramide-monohexoside (m/z) 804.4 (CMH(d18:1C22:1+Na)(+)) also increased after reperfusion and correlated with extent of liver injury after reperfursion.</p><p><b>CONCLUSIONS</b>Three main forms of sphingolipids, ceramide, sphingomyelin and ceramide-monohexoside, are related to hepatic I/R injury and provide a new perspective in understanding the mechanisms responsible for hepatic I/R injury.</p>