Abstract
The quantjtative bioasaay test for human chorionic gonadotropin, employing the femaleXnnosps laevis toad, has proven its clinical usefulness in a series of 372 patients. Other biological and immunological pregnancy tests are also investigated simultaeneously for comparative purposes.
1) 249 cases of normal pregnancy, using Xenopus pregnancy test, were studied. The accuracy of the test was found to be 98%.
2) In the series of 20 cases suspected of pregnancy and before Day 40, the test has given correct positive results of 95%.
3) The semiquantitative analysis of urinary HCG from Day 33 to terms of pregnancy was investigated. Between Day 33 and 40, maximal excretion of urinary HCG was 500 X. U. per liter of urine. After Day 40, a consistent elevation of the titer was observed. The maximal excretion occurred at Day 67 (8300 X. U.). By Day 120, the level had decreased to a relatively steady state of less than 1000 X. U.. These results followed the characteristic curve described by other investigators employing both biologic and immunologic technics. Moreover, since HCG levels reach its highest level after Day 40, just when nausea and vomiting are most common, it seems that there is some relationship between chorionic gonadotropin levels, and nausea and vomiting of pregnancy.
4) In the group of threatened abortion with good recovery, it was noted that urinary HCG levels were within normal ranges in most of the cases. On the other hand, threatened abortions, preceded by a fall in HCG levels less than minimum titer in each lunar month of normal pregnancy, did not carry through successfully to term. The test was also of definite prognostic value in the groups of incomplete abortion, missed abortion, suspected intrauterine fetal death and habitual abortion.
5) Similar results, as reported in the other pregnancy tests, were obtained in the groups of hyperemesis gravidarum, hydatidiform mole, chorioepithelioma, ectopic pregnancy and hydrocephallus.
6) In Xenopus prgnancy test, there was no incorrect response in the differential diagnosis with other non-pregnant dlseases, but in Friendman test performed simultaeneously, one incorrect negative response of five cases was observed.
7) In the controlled temperature laboratory, there was no significant influence on induction of ovulation throughout different seasons in Xenopus laevis.
8) Same urine samples were used for comparative studies between Xenopus pregnancy test and immunological UCG-test. Strong correlation was noted in both tests.
9) The mode of life of Xenopus laevis is considerably different from that of other Rana and Bufo. The breeding is very simple. The test is simpler to perform, as compared with other biological tests-one simple injection through dorsal lymph sac. The reading of the reaction is the simple gross observation of the eggs in the water. In addition, in these experiments, each toad was used over 40 times and still responds satisfactorily, so it is very inexpensive. From the above-mentioned data, the author believes the test is one of the excellent pregnancy tests.
