Liproprotein inhibitor of bone marrow cells in tumor-bearing rats.

The role of a plasma inhibitor of erythropoiesis is evaluated in rats with Walker-256 carcinoma (W-256). Plasma from tumor-bearing rats was treated by gel filtration chromatography (Sephadex G-150) and fractions were combined into four pools on the basis of mol. wt. Inhibitory activity was assayed by adding an aliquot of the plasma fractions to normal rat marrow cells which were cultured for 24 hr with and without erythropoietin. 59Fe-heme synthesis, [3H]thymidine DNA synthesis, and 14C-leucine protein synthesis were studied. The results indicated that cultures containing the high mol. wt. pool (greater than 400,000 daltons) had significantly decreased heme, DNA and protein synthesis. This inhibitor also diminished the response to erythropoietin in polycythemic mice. The lower mol. wt. pool stimulated heme synthesis in vitro. To identify the inhibitor further, plasma lipoprotein classes were isolated by density gradient ultracentrifugation. The very low density lipoprotein (VLDL) and chylomicron fractions markedly inhibited DNA, protein and heme synthesis. Low density and high density lipoprotein fractions were inactive. A lipoprotein inhibitor of erythropoiesis was also identified in cancerous ascitic fluid, and to a lesser degree, in normal rat plasma. We suggest that this VLDL inhibitor of marrow erythropoiesis is a contributing factor in the anaemia of cancer.     

Shear inactivation of cellulase of Trichoderma reesei

Inactivation of the cellulase of Trichoderma reesei (EC 3.2.1.4) by shear, is of sufficient magnitude to merit consideration in the design of equipment for the enzymatic hydrolysis of cellulose. The inac inactivation constant, k_d, is a function of the flow rate of the enzyme solution through a fine capillary tube. k_d increased slowly at low shear stress, and much more rapidly when the shear stress was greater than 15 dynes cm^?2.     

The H-phosphonate approach to the solution phase synthesis of linear and cyclic oligoribonucleotides.

The solution phase synthesis of the tetraribonucleoside triphosphate r(ApCpGpU) 18 and the corresponding cyclic tetraribonucleotide 19 is described. The synthetic methodology is based on 5'- O -(DMTr)-2'- O -(Fpmp)-ribonucleoside-3'- H -phosphonate building blocks 10. Coupling, which is rapid and quantitative, is effected with di-(2-chlorophenyl) phosphorochloridate 5 at -40 degreesC; it is followed by in situ treatment with 2-(4-methyl-phenyl)sulphanyl-1 H -isoindole-1,3(2 H )-dione 6b. The resulting sulphur transfer reaction also proceeds rapidly and quantitatively at -40 degreesC. The same coupling and sulphur transfer steps are used in the cyclization reaction, but a 5'- H -phosphonate intermediate 24 is involved. The final three-step unblocking process involves treatment with (i) E -2-nitrobenzaldoxime 7 and N 1, N 1, N 3, N 3-tetramethylguanidine (TMG) 8 in aceto-nitrile, (ii) concentrated aqueous ammonia at 50 degreesC and (iii) 0.5 mol/dm3sodium acetate buffer (pH 4.0) at 40 degreesC. The fully unblocked products 18 and 19 were characterized by NMR spectroscopy and by enzymatic digestion.     

Cloning and expression of hbves, a novel and highly conserved mRNA expressed in the developing and adult heart and skeletal muscle in the human

bves is a novel mRNA expressed in the developing heart in chick and mouse. Here we describe hbves, the human homolog of chick and mouse bves. Northern and dot blot analyses reveal restricted expression in the heart and skeletal muscle in the embryo and adult. BLAST searches of the NCBI databases confirm that hbves is novel. Portions of the sequence are an exact match with genomic PAC 52202, which localizes to Chromosome (Chr) 6q21. Presumably, these matches and intervening sequences match the intron-exon borders of the gene. Computer conformation analysis of the derived amino acid predicts three transmembrane helices with an extracellular C-terminus that is conserved in chick, mouse, and human. bves is highly conserved among all three species at the amino acid level with 75% identity and 92% similarity. Received: 15 February 1999 / Accepted: 29 April 1999     

Epithelial-mesenchymal interactions in prostatic development. I. morphological observations of prostatic induction by urogenital sinus mesenchyme in epithelium of the adult rodent urinary bladder

Tissue recombinants of embryonic urogenital sinus mesenchyme (UGM) and epithelium of the urinary bladder (urothelium, BLE) of adult rats and mice were grown for 3-30 d in male syngeneic hosts. Short-term in vivo growth indicated that prostatic morphogenesis is initiated as focal outgrowths from the basal aspect of the adult urothelium. The solid epithelial buds elongate, branch, and subsequently canalize, forming prostatic acini. After 30 d of growth in the male hosts, prostatic acini exhibit secretory activity. The marked changes in urothelial morphology induced by the UGM are accompanied by the expression of fine- structural features indicative of secretory function (rough endoplasmic reticulum, Golgi apparatus, and secretory granules). During this process, urothelial cells express prostatic histochemical markers (alkaline phosphatase, nonspecific esterase, glycosaminoglycans) and prostate-specific antigens. The expression within BLE of prostatic characteristics is associated with the loss of urothelial characteristics. These data indicate that adult urothelial cells retain a responsiveness to embryonic mesenchymal inductors. Furthermore, mesenchyme-induced changes in urothelial cytodifferentiation appear to be coupled to changes in functional activity.