Showing papers by "Rosalyn S. Yalow published in 1981"
TL;DR: The demonstration that antigen restricted from transplacental passage can be transferred while complexed to antibody raises the question whether such fetal exposure would induce partial or total immunologic unresponsiveness subsequently if the fetus were rechallenged with the same antigen.
Abstract: The passage of plasma proteins across the placental barrier in humans is known to be highly selective. Thus, free maternal insulin has been reported not to cross the normal maternofetal barrier, although insulin-binding antibodies have been detected in newborn infants whose diabetic mothers received insulin therapy. In this report we demonstrate, with the use of a human antiserum that permits distinction between human and animal insulins, that insulin in the cord blood of each of two neonates of insulin-treated diabetic mothers was, in part, animal insulin. The higher the antibody titer of the mother the greater was the total insulin in the cord plasma and the greater was the fraction that was animal insulin. In case 1 cord plasma insulin was 0.7 unit/liter, of which 10% was animal insulin; in case 2 cord plasma insulin was 3.5 units/liter, of which 25% was animal insulin. The demonstration that antigen restricted from transplacental passage can be transferred while complexed to antibody raises the question whether such fetal exposure would induce partial or total immunologic unresponsiveness subsequently if the fetus were rechallenged with the same antigen.
59 citations
TL;DR: Fractionation on Sephadex G-50 and starch gel electrophoresis combined with radioimmunoassay using three antisera of different specificities are consistent with the hypothesis that a major fraction of big iCCK may represent intact cholecystokinin with a COOH-terminal extension, as has recently been suggested for gastrin.
Abstract: Two major classes of immunoreactive cholecystokinin peptides (iCCK) have been identified in rat and pig brains: (i) large basic peptides (big iCCK) resembling the 33-amino acid porcine cholecystokinin (pCCK33) in size and charge; (ii) small acidic peptides (small iCCK) resembling the COOH-terminal fragments of CCK. Boiling 0.1 M HCl maximally extracts big iCCK; boiling 0.1 M NaOH maximally extracts small iCCK. The differences in hormonal forms removed by these extractants are not likely to be due to enzymatic conversion during the extraction procedures. Fractionation on Sephadex G-50 and starch gel electrophoresis combined with radioimmunoassay using three antisera of different specificities--(i) directed towards the NH2 terminus of pCCK33, (ii) produced by immunization with COOH-terminal fragment CCK8, (iii) produced by immunization with COOH-terminal fragment CCK4--are consistent with the hypothesis that a major fraction of big iCCK may represent intact cholecystokinin with a COOH-terminal extension, as has recently been suggested for gastrin, a molecule having a COOH-terminal pentapeptide identical with that of cholecystokinin.
31 citations
TL;DR: It is concluded that ACTH and insulin are not brain/gut peptides and that guinea pig tissues do not contain measurable pork-like insulin in several radioimmunoassay systems.
24 citations
TL;DR: This chapter presents an overview of the immunochemical studies relating to cholecystokinin in the brain and gut and discusses the two discoveries that have contributed to the current surge of interest in immunochemistry studies of CCK.
Abstract: Publisher Summary This chapter presents an overview of the immunochemical studies relating to cholecystokinin in the brain and gut. Cholecystokinin (CCK) is a central nervous system (CNS) peptide. It is exceptional in its high brain concentration—far exceeding the brain concentrations of other brain–gut peptides—and remarkable in its abundance and broad distribution throughout the cerebral cortex. It is further unusual in the variety of its heterogeneous molecular forms; these are distributed differently in brain and gut tissues. Both intact CCK-33 and its COOH-terminal fragments are found in the brain as well as in the gut. The chapter discusses the two discoveries that have contributed to the current surge of interest in immunochemical studies of CCK. The COOH-terminal approach is preferred for the measurement of CCK peptides in gastrin-free tissue extracts but is not applicable to the measurement of plasma CCK because of the relative abundance of gastrin peptides in plasma and their strong cross-reactivity in this assay.
23 citations
TL;DR: The fraction of immunoreactivity in the form of a CCK-33-like peptide was greater, although the total recovery was less, in acid extractants of whole gut, and this was the case for the extraction of secretin from the same tissue.
18 citations
TL;DR: Using radioimmunoassay, cholecystokinin and enkephalin levels were determined in the brain and gut of rats following ethanol administration, which contrasts with the reports of altered levels of several classical neurotransmitters after ethanol administration.
14 citations
TL;DR: Fractionation on Sephadex G50 and starch gel electrophoresis combined with radioimmunoassay using 3 antisera of different specificities are consistent with the hypothesis that a major fraction of Big iCCK may represent intact CCK with a COOH-terminus extension as has recently been suggested for gastrin.
11 citations
TL;DR: Pork insulin recombined from cleaved A-and B-chains of pancreatic insulin was shown to be identical with the pancreatic hormone both in EHR assays and in immunoassays employing four different antisera, including two species-specific human anti-insulin sera as discussed by the authors.
Abstract: Pork insulin recombined from cleaved A- and B-chains of pancreatic insulin was shown to be identical with the pancreatic hormone both in erythrocyte receptor assays and in immunoassays employing four different antisera, including two species-specific human anti-insulin sera. Pancreatic human insulin and that prepared from recombined bacterially synthesized A- and B-chains were also indistinguishable in the same systems. This study demonstrates that the prohormone stage of either human or porcine insulin is not required to preserve potency of membrane binding or immunochemical reactivity, even employing an antiserum with marked species specificity.
4 citations
TL;DR: Immunoreactive secretin concentrations were measured in femoral venous plasma and in intestinal perfusates during acid and neutral perfusion of small intestinal segments in anesthetized rabbits.
Abstract: Immunoreactive secretin concentrations were measured in femoral venous plasma and in intestinal perfusates during acid and neutral perfusion of small intestinal segments in anesthetized rabbits. Steady-state plasma and luminal secretin concentrations were less than 20 pg/ml. Duodenal perfusion with with 0.1 N hydrochloric acid stimulated peak plasma immunoreactive secretin concentrations of 200 - 300 pg/ml within five minutes. Acid stimulated plasma concentrations remained constant during 30 minutes of perfusion. Secretin output into the acid perfusate (2000 - 4000 pg/min) accompanied the release into plasma. Subsequent perfusion with a neutral solution resulted in a rapid return to steady-state plasma and luminal secretin concentrations. Sequential acid perfusion of the ileum, jejunum, and duodenum stimulated similar concentrations of secretin in plasma and luminal perfusates.
4 citations