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Determination of lethal dose in a protozoa: screening of contrast media toxicity
Abstract:
Suitability of a protozoan culture for determination of contrast media (CM) toxicity was investigated. A culture of Blepharisma americanum was exposed to varying concentrations of CM and the time elapsed until 50% cell mortality was determined. The cultures were standardized using solutions of Na iothalamate and/or Metrizamide. A standardized culture responded reproducibly between days 6 and 10 of the culture age. Comparison of concentrations of CM needed to achieve LD50 at 7 minutes ranked CM in order of decreasing toxicity as follows: oral cholecystopaques, intravenous cholecystopaques, and urographic agents; ie ionic monomers, ionic dimers, monovalent dimers, nonionic monomers, nonionic dimers. Comparison of CM toxicity determined by protozoa LD50 at 7 minutes with i.v. LD50 in mice showed a good correlation, suggesting usefulness of the protozoan assay as a complementary or screening toxicologic method.
Insights
This study explored using protozoan cultures to test contrast media (CM) toxicity. The Blepharisma americanum assay showed good correlation with mouse toxicity, suggesting its use as a screening tool for CM safety.
Area of Science:
- Toxicology
- Cell Biology
- Pharmacology
Background:
- Contrast media (CM) are essential in medical imaging.
- Assessing CM toxicity is crucial for patient safety.
- Existing toxicity testing methods can be time-consuming and resource-intensive.
Purpose of the Study:
- To investigate the suitability of a protozoan culture, Blepharisma americanum, for determining contrast media toxicity.
- To establish a reproducible protozoan assay for contrast media toxicity screening.
- To compare the toxicity ranking of various contrast media using the protozoan assay with established in vivo data.
Main Methods:
- Cultured Blepharisma americanum were exposed to varying concentrations of different contrast media.
- The time to achieve 50% cell mortality (LD50) at 7 minutes was determined for each contrast medium.
- Cultures were standardized using Na iothalamate and Metrizamide solutions.
- Protozoan assay results were compared with intravenous LD50 data in mice.
Main Results:
- A reproducible response was observed in standardized protozoan cultures between days 6 and 10.
- Contrast media were ranked by decreasing toxicity: oral cholecystopaques, intravenous cholecystopaques, and urographic agents (ionic monomers, ionic dimers, monovalent dimers, nonionic monomers, nonionic dimers).
- A good correlation was found between protozoan LD50 at 7 minutes and intravenous LD50 in mice.
Conclusions:
- The Blepharisma americanum protozoan assay is a suitable method for assessing contrast media toxicity.
- The protozoan assay provides a toxicity ranking that correlates well with in vivo mouse data.
- This protozoan assay can serve as a complementary or preliminary toxicologic screening method for contrast media.
