Radiotoxicity of platinum-195m-labeled trans-platinum (II) in mammalian cells
- Univ. of Medicine & Dentistry of New Jersey, Newark, NJ (United States)
- Harvard Medical School, Boston, MA (United States)
- Oak Ridge National Lab., TN (United States)
- Univ. of Massachusetts, Amherst, MA (United States)
The chemotoxicity and radiotoxicity of trans-dichlorodiammineplatinum (II) labeled with {sup 195m}Pt (trans-{sup 195m}Pt) are investigated to ascertain the potential of radioplatinum coordination complexes as antineoplastic agents. Platinum-195m, with a half-life of about 4 days, is a prolific emitter of low-energy Auger electrons because of the high probability of internal conversion in its isomeric transitions. The kinetics of cellular uptake and retention after incubation and the radiotoxicity of this Auger electron emitter in the form of trans-{sup 195m}Pt is investigated using cells of the Chinese hamster V79 cell line. The cellular uptake of {sup 195m}Pt reaches a plateau in about 3 to 5 h of incubation and varies nonlinearly with the extracellular concentration of radioactivity. The radioactivity is eliminated from the cells after incubation with an effective half-life of 24 h. Cell survival data, when corrected for the chemical toxicity of nonradiolabeled trans-platinum, give a cell survival curve typical for radiations with high linear energy transfer. At 37% survival, the mean lethal cellular uptake is about 1.0 mBq/cell. Dosimetric considerations, based on subcellular distribution of the radionuclide, yield a value of 4.8 for the relative biological effectiveness when compared with 250 kVp X rays. Theoretical Monte Carlo track-structure calculations indicate that the density of radical species produced in liquid water in the immediate vicinity of a {sup 195m}Pt decay site is substantially greater than the density of species along the track of a 5.3 MeV {alpha} particle. This explains qualitatively the efficacy of {sup 195m}Pt in causing high-LET radiation type biological effects. 48 refs., 6 figs., 1 tab.
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 79331
- Journal Information:
- Radiation Research, Vol. 140, Issue 1; Other Information: PBD: Oct 1994
- Country of Publication:
- United States
- Language:
- English
Similar Records
Biological effect of lead-212 localized in the nucleus of mammalian cells: Role of recoil energy in the radiotoxicity of internal alpha-particle emitters
Biodistribution and pharamacokinetics of /sup 195m/Pt-labeled cis-dichlorotrans-dihydroxo-bis(isopropylamine)platinum(IV), CHIP, in normal female Fischer 344 rat