Relationships between serum (ZZ)-bilirubin, its subfractions and biliverdin concentrations in infants at 1-month check-ups.

In 150 infants, including those with breast milk jaundice, who were brought to our hospital for their 1-month check-ups, the serum concentrations of (ZZ)-bilirubin, its subfractions and biliverdin were measured by high-performance liquid chromatography and the relationships among them investigated. (ZZ)-Bilirubin was found to have the highest serum concentration, followed by (ZE)-bilirubin, accounting for 14.0 (geometric mean) % of (ZZ)-bilirubin. Biliverdin had a serum concentration of 0.95% of (ZZ)-bilirubin. There was only a small amount of total (di- and mono-) glucuronosyl bilirubin, 0.42% of (ZZ)-bilirubin. (ZE)-Bilirubin, (EZ)-bilirubin, (EZ)-cyclobilirubin. biliverdin, diglucuronosyl bilirubin and monoglucuronosyl bilirubin (C-8 and C-12) showed positive logarithmic correlations with (ZZ)-bilirubin (R2=0.16 or above, P<0.05). (ZE)-Bilirubin showed a significant positive logarithmic correlation with (ZZ)-bilirubin (R2=0.863, P<0.0001). Furthermore, (EZ)-cyclobilirubin, the most important photoisomer in phototherapy for neonatal hyperbilirubinaemia, was detected in very small amounts in approximately half of the neonates (84 of 150) when they were in conditions of only weak ambient light. The relationship between total glucuronosyl bilirubin and (ZZ)-bilirubin concentrations fitted a model of saturation kinetics of bilirubin UDP-glucuronosyltransferase.

Differential growth response of normal human diploid fibroblasts and in vitro transformed human fibroblasts in serum-free defined culture medium.

Two neoplastic human cell lines, WI-38 CT-1 and SUSM-1, which were transformed in vitro with gamma rays and 4-nitroquinoline 1-oxide, respectively, grew continuously in a serum-free defined medium. The defined medium used was a 1:1 mixture by volume of Dulbecco's modified Eagle's medium and Ham's F12 (DF) supplemented with 0.1% bovine serum albumin fraction V, 10 micrograms/ml of transferrin, 1 microgram/ml of insulin, and 5 micrograms/ml of oleic acid. In the case of SUSM-1, 100 micrograms/ml of fetuin were added to cultures when the cells were subcultured. Under these conditions the growth rates of the two transformed human cell lines were almost the same as those in a DF medium containing 10% fetal bovine serum (FBS). In addition, the defined medium permitted the cells to grow indefinitely without a lag period when they were transferred from serum-containing medium into this defined medium, indicating that no selection or adaptation of the cells had occurred. Interestingly, these cell lines did not require for their growth any polypeptide growth factors such as epidermal, platelet-derived or fibroblast growth factors. On the other hand, the control WI-38 cells stopped growing in the defined medium after about 2 divisions. Another control normal cell strain of fibroblasts derived from a human embryo showed a decreased growth rate in the defined medium as compared with that in the DF medium with 10% FBS. These results suggest that the defined medium described here is useful for the selective growth of human cells transformed in vitro after treatment with carcinogens from an untransformed cell population. In addition, the defined medium for transformed human cells should contribute to studies on their growth mechanisms.