AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
The reaction of azomethine dyes (1a - g) with malonodinitrile (2) gives dicyanomethylene-pyrazolin-5-one (4) which immediately reacts with the eliminated anilines by HCN-amine exchange giving the deeply coloured arylamino-cyanomethylene-pyrazolinones (5a-g). Structural investigations and a study of the absorption characteristic are described.
Bovine placental lactogen (bPL) has been purified to homogeneity from bovine placental tissue. A radioreceptor assay (RRA), using a pregnant rabbit liver membrane fraction and human GH (hGH) as standard and tracer, was employed to monitor hormonal activity during the purification. The apparent molecular weight of bPL is approximately 30,000*32,000 as determined by analytical sodium dodecyl sulfate polyacrylamide gel electrophoresis. Somewhat larger estimates were obtained upon Sephadex gel filtration columns. The isoelectric point of the purified hormone as determined by analytical polyacrylamide gel isoelectric focusing is 5.5. The binding and displacement curves of radioiodinated bPL and hGH in the RRA for GH are superimposable, whereas the displacement curve of bPL in the RRA using the particulate fraction of a pregnant rat liver homogenate is parallel to the ovine PRL standards. Purified bPL is capable of modulating hGH-specific receptor sites in cultured human IM-9 lymphocytes. Stimulation of the growth of quiescent Nb2 node lymphoma cells in culture demonstrates that bPL and bovine PRL are equipotent in this bioassay.
The Nb2 lymphoma cell bioassay was validated as a suitable tool for the measurement of lactogenic activity in bovine serum samples obtained during pregnancy. The levels of bovine PRL detected by homologous immunoassay and the levels of total lactogenic activity determined by bioassay were virtually identical in serum samples obtained from pregnant cows, suggesting that serum bovine placental lactogen (bPL) values in pregnancy are very low or absent in the cow. Random samples of milk from pregnant animals as well as amniotic and allantoic fluid samples were also found not to contain measurable levels of bPL. On the other hand, fetal serum bPL levels were detected by the Nb2 bioassay.
