Gene Literature Dashboard

This study compares the estrogen receptor (ER) content of 26 breast neoplasms as determined by dextran-coated charcoal (DCC), fluorescein-labeled estradiol conjugate (FITC) on frozen sections, and immunoperoxidase (IP) on sections of formalin-fixed, paraffin-embedded tissues. Concordance between results of the three technics was found in 16 (62%) cases. DCC and IP agreed in 18 (69%) cases, DCC and FITC agreed in 22 (85%) cases, and IP agreed with FITC in 18 (69%) cases. Most of the concordant cases (15/16) were in patients with ER-positive neoplasms. The relative merits and applications of the three technics are discussed.

The multiple point dextran coated charcoal technique with Scatchard analysis (DCC) and isoelectric focusing on polyacrylamide gels (IF) were compared with regard to steroid receptor recovery, amount of tissue necessary, and expenses of assay. Quantitative correlations showed that when using DCC as compared to IF, estradiol receptor (ER) recovery increased two and progesterone receptor (PgR) recovery increased four times. In spite of lower recovery, IF may be a good alternative to DCC for routine ER assay since a small amount of tissue is required and the IF assay is easy to evaluate. The two assays were approximately equal in expense.

Pentosan polysulphate (PPS, Hemoclar, MW 6,700) was observed to have a low affinity for ATIII-Sepharose eluting at 0.3M NaCl. Tested in vitro it had, as previously reported, a low potency as an anticoagulant, about 10 times less than heparin on a weight for weight basis. Only the KCCT was affected by low concentrations of PPS unlike heparin by which both thrombin time and KCCT were affected. Upon injection of PPS subcutaneously (50mg) the heparin activity measured by chromogenic anti factor Xa and by KCCT was in the ratio of 2:1. When injected intravenously (40mg) into 3 healthy volunteers a significant prolongation of a modified prothrombin time was observed in 2 subjects. When PPS was added to heparin containing plasma it was observed to completely inhibit heparin at low concentrations (2:1 on a weight to weight basis) when measured in the thrombin and prothrombin time but not in the KCCT. The antiheparin effect of PPS was also observed in a purified system in obviating the heparin potentiation of the rate of inhibition of thrombin by antithrombin III. Observations showed that at higher concentrations of PPS it acted by directly inhibiting thrombin without the intervention of antithrombin III but also to potentiate the rate of fibrin monomer polymerization.

Antithrombin III (ATIII) is an important plasma protease inhibitor with a central role in the coagulation system. On the basis of its protein sequence, ATIII is one member of a "super family" of protease inhibitors that includes alpha 1-antitrypsin and chicken ovalbumin. An increased risk of thromboembolism is associated with inherited ATIII deficiency. To study the structure and expression of the human ATIII gene, we have isolated complementary (cDNA) clones for ATIII from human liver mRNA. ATIII cDNA clones were identified by hybridization to a mixture of synthetic oligodeoxynucleotides encoding amino acids 251-256 of the ATIII protein sequence. The largest cDNA clone (1.4 kilobases) included the coding region of ATIII mRNA from codon 10 through a 3'-untranslated region. Comparison of ATIII cDNA clones from two different sources revealed a sequence polymorphism at an internal PstI restriction site. Analysis of both total genomic DNAs and an ATIII gene cloned in a bacteriophage Charon 4A showed that the ATIII gene is present once per haploid genome and is distributed over 10-16 kilobases of DNA. Computer-assisted comparison of the cDNA sequence with those for baboon alpha 1-antitrypsin and chicken ovalbumin revealed homologies consistent with their inclusion in the protease inhibitor superfamily.

The transbilayer mobility of phosphatidylcholine (PC) molecules in the membrane of homozygous reversible sickle cells (RSCs) was studied using a PC-specific exchange protein from beef liver. In deoxygenated RSCs, all of the PC present in the membrane of the intact cell is rapidly available for exchange, mediated by this protein. Since a substantial amount of the PC is present in the inner membrane leaflet of these cells, this observation implies that the PC molecules in their membranes do experience rapid transbilayer movements. To determine the actual rate of transbilayer movement of the PC, radioactive PC was introduced into the outer monolayer of oxygenated RSCs using the PC-specific exchange protein. Subsequently, the cells were incubated at 37 degrees C under oxy- and deoxygenating conditions to enable the PC to equilibrate within the bilayer. At various time intervals, samples were taken and treated with phospholipase A2, which selectively degrades the PC in the outer monolayer. Analysis of the specific radioactivities of the lyso-PC thus produced, as well as of the residual PC, enabled us to follow the fate of the radioactive PC previously introduced into the outer membrane layer. The half-time value for transbilayer equilibration of the PC in deoxygenated RSCs was determined to be 3.5 h, which is about four times lower than that for oxygenated RSCs. This increased transbilayer mobility of PC, observed in deoxygenated RSCs, is immediately restored to the normal low rate upon reoxygenation of the cells, indicating a complete reversibility of this phenomenon.

Equilibrium dialysis was used to examine the binding of Ga-67 to horse spleen ferritin (HFE), and the ability of this protein to remove Ga-67 originally bound to human transferrin (TF). Seventy hours were required for the HFE to bind 70% of the activity. When HFE was placed in competition with preformed TF-Ga-67 complex, little nuclide was translocated to HFE. Upon the addition of compounds of low molecular weight that occur intracellularly, this transfer was dramatically enhanced. In the presence of 1 mM adenosine triphosphate (ATP), the most effective mediator examined, the final distribution was 17% bound to TF and 62% to HFE, with 16% not protein-bound. In the absence of any mediator, the same distribution was 84, 6, and 3%. Control experiments with ATP showed that little radionuclide was transferred from TF to albumin. These results add support to the previous suggestions of the potential role of ferritin in Ga-67 localization.