This study re-evaluated the colorimetric assay for cytidine deaminase (CTD), and showed that the optimum conditions were pH 7.5, 37 degrees C, and up to 24 h. In addition, this method was found to require protein precipitation. Following these modifications, intra-assay and inter-assay coefficients of variation were below 5 per cent, indicating that the assay was highly reliable. CTD activity was determined in 282 serum samples from 206 normal pregnant women by the incubation of 100 microliters of serum and 400 microliters of 1.4 mmol/l cytidine substrate for 16 h at 37 degrees C. Following protein precipitation, the ammonia liberated during conversion was measured by a colorimetric procedure. The mean (+/- SD) CTD activity was 7.31 +/- 2.50 U at 3-12 weeks of gestation, 8.70 +/- 2.12 U at 13-24 weeks, 7.59 +/- 2.25 U at 25-36 weeks, and 7.29 +/- 2.16 U at 37-42 weeks. High levels of CTD activity were found in patients with abruptio placentae and amnionitis associated with intrauterine fetal death (IUFD). The increase in CTD activity was noted from 3 days to 1 week before the confirmation of IUFD. The placenta contains extremely high levels of CTD, but cord serum does not. Thus, the excessive elevation of CTD activity was probably derived from progressive placental damage. This modified CTD assay was concluded to be simple and reliable, and may perhaps be useful in detecting pregnancy disorders.

The CTD activity in abnormal pregnancies was excessively elevated due to a damaged placenta under progressive deterioration. This CTD assay was simple and had predictive value for the prognosis of an infant of an abnormal pregnancy.

No abstract

An improved semiquantitative immunoassay method allows human luteinizing hormone (hLH) in urine to be detected from 2.5 to 640 mIU/ml has developed. With this method, the hLH surges in every 3 h urine samples while awake were measured in 8 normal and 12 infertile women. The result was that the urinary hLH surge in infertility was insufficient regardless of the high urinary E2 value. This result may play, at least in part, an etiologic role in infertility.