Auer-rod positive myelocytic leukemia cells in diffusion chambers: differentiation along the eosinophilic pathway

Auer-rod positive acute myelocytic leukemia (AML) blasts from a 33-year-old patient were cultured in diffusion chambers (DC) in order to test their differentiation potential. The cells were labeled with anti-human granulocyte anti-serum known to be negative for eosinophils, and evaluated using the unlabeled peroxidase-antiperoxidase (PAP) method. Parallel to a decline in the number of leukemic blasts there was an increase of up to 86% in the number of granulocytic cells belonging to the eosinophilic series. Auer-rod bodies were found in the eosinophilic cells even after 20 days in culture. Staining with anti-granulocyte antiserum failed to demonstrate positive cells at any time during DC culture. Based on the negative reaction with the anti-granulocytic antibodies already at an early stage of development evidence is provided for the existence of a progenitor cell exclusively committed to the eosinophilic pathway.     

A 17-bp insertion and a Phe215----Cys missense mutation in the dihydrolipoyl transacylase (E2) mRNA from a thiamine-responsive maple syrup urine disease patient WG-34.

We have amplified the cDNA for the transacylase (E2) subunit of the branched-chain alpha-ketoacid dehydrogenase (BCKAD) complex from a thiamine-responsive MSUD cell line (WG-34) by the polymerase chain reaction. Sequencing of the amplified WG-34 cDNA showed a 17-bp insertion (AAATACCTTGTTACCAG) apparently resulting from an aberrant splicing of the E2 gene, and a missense (T----G) mutation that changes Phe215 to Cys in the E2 subunit. The existence of these two mutations was confirmed by probing the amplified E2 cDNA or genomic DNA with allele-specific oligonucleotides. The above results support the thesis that the thiamine-responsive MSUD patient (WG-34) is a compound heterozygote at the E2 locus. The implication of the E2 mutations for the thiamine-responsiveness observed in this patient is discussed.     

Purification and structure of caltrin-like proteins from seminal vesicle of the guinea pig

Two different small proteins that cross-react with the antiserum against bovine caltrin (calcium transport inhibitor) have been purified from the seminal vesicle contents of the guinea pig. The primary structure and some molecular characteristics of the pure proteins are reported. The two proteins interact with concanavalin A indicating the presence of carbohydrates in their molecules. Chemical deglycosylation with trifluoromethanesulfonic acid, after reduction and carboxymethylation, results in complete loss of affinity for the lectin. Removal of sugar components from the structure destroys the ability of caltrin-like proteins to react with antibodies to bovine caltrin. The protein moving faster on polyacrylamide gel electrophoresis is designated guinea pig caltrin I, the other is II. They contain 45 and 55 amino acids, and the molecular weights of the peptide portions are 5082 and 6255, respectively. Although they have entirely different amino acid sequences, they share some common features: recognition by rabbit antibodies to bovine caltrin, the predominance of basic residues and the presence of 3 cysteine residues in fraction I and 8 in fraction II. The proteins have pI values of 9.5 and 10.2, respectively, which are consistent with the amino acid composition. The two pure fractions are approximately equally effective, on a weight basis, as inhibitors of 45Ca2+ uptake by guinea pig spermatozoa. The data presented reinforce the hypothesis that caltrin-like proteins are responsible for the previously reported (Coronel, C.E., San Agustin, J., and Lardy, H.A. (1988) Biol. Reprod. 38, 713-722), calcium-transport inhibitor activity detected in reproductive tract fluid from adult male guinea pigs.     

Trisomy 13 in a 4-year-old child

Summary The karyotype 47,XY,13+ was observed in a mentally retarded four-year-old child, with numerous abnormalities and the typical dermatoglyphics of a trisomy 13. Banding analysis showed a complete extra chromosome 13.     

Functional effects of thymopoietin32-36 (TP5) on cytotoxic lymphocyte precursor units (CLP-U). I. Enhancement of splenic CLP-U in vitro and in vivo after suboptimal antigenic stimulation

Cytotoxic lymphocyte precursor units (CLP-U) were enumerated in the spleens of C57BL/6 mice 3 days after i.p. injections of synthetic thymopoietin32-36 (TP5). One hundred to 1000 ng TP5/mouse potentiated splenic CLP-U, this effect being detectable only after suboptimal allogeneic sensitization (with 1.2 x 10(5) mitomycin-C treated DBA cells). This elevation of CLP-U persisted in the injected mice for at least 14 days. Control peptide did not affect CLP-U. In vitro incubation of 0.01 to 0.1 ng/ml of TP5 with normal C57BL/6 spleen cells also enhanced CLP-U after suboptimal allogeneic stimulation; high concentrations of TP5 caused suppression of CLP-U and this was detectable with optimal sensitization conditions. Thus TP5, in vitro and in vivo, appears to regulate immune responsiveness and this regulation varies with TP5 dosage and with the immune stimulus.     

Increase in liver acid lipase of thyroidectomized rats by thyroid hormones and its inhibition by actinomycin D.

Acid lipase activity in the livers of thyroidectomized rats is increased by administration of L-thyroxine. The response is dose-dependent and can be demonstrated within 12 h after treatment. L-Triiodothyronine also evokes a rapid increase in acid lipase activity, and this increase can be inhibited by coadministration of actinomycin D.     

Covalently closed circular DNAs in closely related unicellular cyanobacteria.

Plasmids of Synechococcus cedrorum and two Anacytsis nidulans strains were characterized physically, and a probable instance of spontaneous "curing" is described.     

The isolation and characterization of a specific antibody population directed against the prothrombin activation fragments F2 and F1 + 2

We have raised antisera against human prothrombin activation fragment F2 in rabbits and have chromatographed the respective immunoglobulin G fractions on prothrombin-Sepharose, Pr1-Sepharose, and F2-Sepharose immunoadsorbents. The specific antibody population obtained was utilized to construct a double antibody radioimmunoassay capable of measuring as little as 0.8 ng/ml of this component. Our studies suggest that the immunoreactive site defined by this antibody population is most probably located within the negatively charged COOH-terminal region of F2. The immunologic expression of this area is unaffected by denaturation or reduction-alkylation of F2 as well as by attachment of polypeptide to the NH2-terminal of this component. However, the presence of covalently bound polypeptide at the COOH-terminal of F2 reduces its immunologic reactivity by 300- to 400-fold. Prothrombin, Pr1, and Pr*1, which contain the F2 region as part of their covalent structure, are at least 4000 to 7000 times less immunoreactive than F2 on a molar basis. Conversion of these components to thrombin as well as activation fragments generates the theoretically predicted level of immunoreactivity. Masking of the immunoreactive site within these zymogens is due to two phenomena. Firstly, covalent attachment of polypeptides on the COOH-terminal of the F2 segment significantly depresses the reactivity of this region. Secondly, a critical S--S bridge aids in the sequenstration of the immunoreactive site. This cross-link may facilitate interactions between the COOH-terminal of the F2 segment and other regions of the zymogen.