• Journal of Applied Biological Chemistry
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• v.64 no.4
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• pp.369-374
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• 2021

Brown blotch disease of oyster mushrooms is caused by tolaasin and its analog peptide toxins which are produced by Pseudomonas tolaasii. Tolaasin peptides form pores in the plasma membrane and destroy the fruiting body structure of mushroom. Lysis of red blood cells, hemolysis, can be occurred by cytotoxic activity of tolaasin. The hemolytic activity of tolaasin is inhibited by metal ions, such as Zn²⁺ and Ni²⁺. When Gadolinium ion was added, a biphasic effect was observed on tolaasin-induced hemolysis, an increase in hemolysis at submillimolar concentrations and an inhibition at millimolar concentrations. The mechanism of gadolinium ion-induced inhibition of tolaasin activity may not be similar to those of the inhibitions by other metal ions. Since gadolinium ion has been reported to change a lateral pressure of lipid membrane by binding to the negative charges of membrane lipids, it may not directly work on the tolaasin channel gating, but rather decrease the stability of tolaasin channel by increasing firmness of membrane.

• Investigative Magnetic Resonance Imaging
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• v.13 no.1
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• pp.81-87
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• 2009

Purpose : We sought to evaluate enhancement of plaque with gadolinium-based contrast agent by magnetic resonance imaging (MRI) in comparison with histopathology, namely lipid-rich and macrophage-rich components that were two representative characteristics of plaque vulnerability using atherosclerotic rabbit aorta in order to determine which histopathologic component is relevant to the enhancement. Materials and Methods : New Zealand white rabbit (n=4, weight 3.0 to 3.5 kg, all male) was used for animal model of atherosclerosis. Atherosclerotic aortic lesions were induced by high-cholesterol diet and double balloon injury. T1-weight axial images were acquired before and after gadolinium-based contrast agent using a 3-T MRI. MR images and the matched histopathological sections (n=35) were divided into 4 quadrants or 3 (n=130). Enhancement ratio (ER, ER=SIpost/SIpre) on MRI was calculated for each quadrant and compared with histopathology in regard to lipid-rich and macrophage-rich areas. Results : Lipid-rich quadrants were 72 and fibrous quadrants were 58. The number of quadrants which had macrophage-rich areas was 105 and that of quadrants which did not have macrophage-rich areas was 25. ER was significantly higher in lipid-rich quadrants than in fibrous quadrants (mean ER 2.25c$\pm$0.41 vs. 2.72$\pm$0.65, p=0.013). ER poorly correlated with macrophage-rich areas when lipid-component was controlled (correlation coefficient -0.203, p=0.236). Conclusion : Lipid-rich plaques showed stronger enhancement than fibrous plaques using a standard gadolinium-based extracellular contrast agent. Macrophage infiltration did not correlate with degree of enhancement. Further study is warranted that account for optimal time of imaging after contrast injection using various plaque models from early to advanced stages and all possible parameters associated with contrast enhancement.

• Investigative Magnetic Resonance Imaging
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• v.15 no.2
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• pp.139-145
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• 2011

Purpose : To assess the frequency and severity of acute adverse reactions to intravenous administration of gadolinium-based contrast agents using computerized reporting system at a single large academic institution. Materials and Methods : We assessed data from electronic hospital information system from October 2008 to December 2010. Reactions were classified as mild, moderate, or severe. We compared the frequency of adverse reactions among three contrast agents (Gd-BT-DO3A, Gd-DTPA and Gd-EOB-DTPA). Results : The total number of administrated contrast agents was 33,600, and the number of administration of Gd-BT-DO3A, Gd-DTPA and Gd-EOB-DTPA were 20,824 (62%), 10,417 (31%) and 2,359 (7%), respectively. Total 39 adverse reactions were reported accounting for 0.1161% of all administrations. The incidences of adverse reactions were 0.1248% (26/39, 67%) for Gd-BT-DO3A, 0.0768% (8/39, 21%) for Gd-DTPA, and 0.2120% (5/39, 13%) for Gd-EOB-DTPA. The difference of frequencies of adverse reaction among three contrast agents was not significant. Most cases of the adverse effect were mild (35/39, 89.7%). Moderate and severe adverse reactions were encountered in two patients, respectively. Conclusion : Among Koreans, adverse effects were rare, and especially, moderate to severe adverse reactions were much rarer. There was no difference among the frequencies of adverse reactions caused by three different contrast agents.