Marla K. Jones

GADOLINIUM-DTPA TRANSPLACENTAL TRANSFER AND DISTRIBUTION IN FETAL TISSUE IN RABBITS

&NA; Novak Z, Thurmond AS, Ross PL, Jones MK, Thornburg KL, Katzberg RW. Gadolinium‐DTPA transplacental transfer and distribution in fetal tissue in rabbits. Invest Radiol 1993;28: 828‐830. rationale and objectives. The authors assessed to what extent the commonly used the magnetic resonance imaging contrast agent, gadopentetate dimeglumine, crosses the placenta. methods. Eight pregnant rabbits in the third trimester were injected with 0.1 mmol/kg of gadopentetate dimeglumine, and killed 5, 15, 30, or 60 minutes after injection. Placental and fetal tissues were analyzed for gadolinium content. results. Placental concentrations of gadolinium were initially high (16.6 ± 3.4 micrograms/gram) and then declined with a biexponential pattern. Initial gadolinium levels in the fetal organs were low and remained so except for the fetal kidneys, which showed increased levels of gadolinium from 4.3 ± 1.1 micrograms/gram at 5 minutes to 6.8 ± 1.8 micrograms/gram at 60 minutes. conclusions. The results indicate that gadolinium does cross the rabbit placenta, and that concentrations in the placenta and the fetal urinary tract are sufficient for imaging as well as possible fetal toxicity.

Transcatheter tubal sterilization in rabbits. Technique and results.

Ross PL, Thurmond AS, Uchida BT, Jones MK, Scanlan RM, Kessel E. Transcatheter tubal sterilization in rabbits: technique and results. Invest Radiol 1994;29:570-573. RATIONALE AND OBJECTIVES.A potential method of nonsurgical tubal sterilization was tested in rabbits. METHODS.Metal coils were designed which could be placed into the uterotubal junction using transvaginal fluoroscopic fallopian tube catheterization. These metal coils were successfully placed unilaterally in the uterotubal junction of 32 rabbits. The contralateral fallopian tube and uterus were used as a control. The rabbits were bred, and the presence of pregnancies was confirmed by palpation. RESULTS.In 21 rabbits (66%), the coil stayed in place. Sixteen rabbits had multiple gestations on the side without the coil and no gestations on the side with the coil. Three rabbits had gestations on both sides, even though the coil was in place, and two rabbits never conceived. In 11 rabbits (34%) the coil was dislodged as early as 5 days and as late as 18 weeks after the procedure. Five of these 11 rabbits had bilateral embryos, 4 had embryos only on the side contralateral to where the coil had been, and 2 never conceived. CONCLUSIONS.The metal coil does prevent conception if it stays in place at the uterotubal junction. However, the coil failed to prevent pregnancy in 3 of 19 rabbits, and was dislodged in 11 rabbits, giving an overall failure rate for contraception of 44%.