A substance found in human placental fluids that inhibits the hemagglutination of H-1 and HB viruses but not that of H-3 or RV viruses, has been purified and found to be an electrophoretically homogeneous glycoprotein stable to heat and a wide pH range. It also appears to be immunologically homogeneous and occurs in the slow a or fast β region.
A novel immunochemical technique for a specific enzymic determination of the myocardial isoenzyme of creatine kinase, CK-MB, involves determination of B-subunit activity of a specimen in which the M-subunit activity has been inhibited by specific antibodies to the M-subunit. Interfering activities from CK-BB isoenzyme, atypical forms of creatine kinase, and adenylate kinase are eliminated by using a blank tube in which all the M-subunit-containing isoenzymes have been removed by a specific immunoprecipitation step. The assay is convenient, linear, and reproducible, and results compare well with those by agarose electrophoresis.
Purified preparations of the glycoprotein found in human placental fluid that inhibits the hemagglutination of H-1 and HB viruses, have also been shown to contain alkaline phosphatase activity. This phosphatase activity has been identified as a placental phosphatase by comparing its characteristic behavior with that of purified human placental alkaline phosphatase. It is probable that the viral inhibitor and the large molecular-weight variant of placental alkaline phosphatase are the same glycoprotein.
Journal Article Immunochemical Determination of LDH-1 Get access Frank Liu, Frank Liu Search for other works by this author on: Oxford Academic Google Scholar Robert Belding, Robert Belding Search for other works by this author on: Oxford Academic Google Scholar Magdalena Usategui-gomez, Magdalena Usategui-gomez Search for other works by this author on: Oxford Academic Google Scholar Gustavo Reynoso Gustavo Reynoso Search for other works by this author on: Oxford Academic Google Scholar American Journal of Clinical Pathology, Volume 75, Issue 5, 1 May 1981, Pages 701–707, https://doi.org/10.1093/ajcp/75.5.701 Published: 01 May 1981 Article history Received: 12 February 1979 Accepted: 04 December 1980 Published: 01 May 1981
An enzymatic, immunochemical test system has been developed which allows quantitation of minute amounts of the Regan isoenzyme of alkaline phosphatase. The basis of the method is the concentration (tenfold) of the Regan isoenzyme by reaction with a monospecific antiserum to placental alkaline phosphatase, insolubilized by polymerization with ethyl chloroformate. This concentration is achieved by incubating heat-inactivated serum with the antibody and by subsequent centrifugation. The pellet containing the active enzyme-antibody complex is immediately assayed for enzyme activity.
We studied sera from 91 normal healthy adults and 112 cancer patients to determine the presence of the Regan isoenzyme. Detectable Regan isoenzyme activity was found in 89 of 91 normal healthy adults. Three of the normal sera contained a level of the isoenzyme that fell above 2 S.D. from the mean. In the case of patients with neoplastic discase, 106 of 112 sera had detectable Regan isoenzyme activity and only 11 sera showed elevated activities. Cancer sera with abnormal Regan levels contained 3 to 300 times the average normal value.
Maternal sera were dialyzed in vitro across individual or combined fetal membranes to elucidate the functions of the membranes in protein transport. Concentration of individual proteins in the dialyzates obtained, closely resembled the composition of amniotic fluid. Results of these in vitro studies indicate that the fetal membranes are able to select protein molecules for passage not only according to size, but also on the basis of their chemical structure.
