Partial resolution of DL-adenosine by template synthesis.

D-Adenosine-5'-phosphorimidazolide reacts very much more rapidly with D-adenosine than with L-adenosine on a poly-D-uridylic acid template. This permits the partial resolution of DL-adenosine. These experiments suggest that segregation of D- and L-nucleotides may have occurred at an early stage in biochemical evolution.

Template-directed synthesis with adenosine-5'-phosphorimidazolide.

Adenosine-5'-monophosphorimidazolide reacts efficiently with adenosine derivatives on a polyuridylic acid template, with the formation of internucleotide bonds.

Particle-associated RNA dependent DNA polymerase and high-molecular-weight RNA in a human cell line derived from polycythemia vera bone marrow.

A particle fraction with a density of 1.15-1.19 g/cm3 was isolated from the cytoplasm of a human cell line established in culture from the bone marrow of an untreated patient with polycythemia vera. Electron micrographs of cross sections of cells and cell homogenates revealed virus-like particles on which DNA could be synthesized. An RNA-dependent DNA polymerase, isolated from the particles, preferred poly(rA)-oligo(dT) over poly(dA)-oligo(dT) and was able to polymerize deoxyguanosine monophosphate in a reaction stimulated by poly(rC)-oligo(dG).

Functions of vitamin E in reproduction and in prostacyclin and immunoglobulin synthesis in rats.

The bioactivities of RRR-alpha-, beta-, gamma-, and delta-tocopherol (T) and R-alpha-tocotrienol (R-alpha-TT) were determined in rat resorption-gestation tests. The ranking order was RRR-alpha-T greater than RRR-beta-T greater than RRR-gamma-T greater than or equal to R-alpha-TT greater than RRE-delta-T. Accordingly, the biopotency of a palm-oil residue was assessed and expressed as alpha-tocopherol equivalents (alpha-TEs). The release of pyruvate kinase, a variable in the nutrition-linked necrotizing myopathy, into the plasma was dose-dependently inhibited by the RRR-alpha-T standard and the corresponding alpha-TE from this residue. Prostacyclin synthesis from aorta segments induced by thrombin or ionomycin was higher than the spontaneous release. However, there was no difference between the depleted group and groups treated with RRR-alpha-T or alpha-TEs from the palm-oil residue. Quantities of IgG in plasma of vitamin E-depleted rats were the highest. Upon supplementation with RRR-alpha-T or alpha-TEs from the palm-oil residue, reduced IgG concentrations were observed, similar to those of animals on a commercial diet containing adequate amounts of vitamin E.

Heparin, carboxyl-reduced sulfated heparin, and Trestatin A sulfate. Antiproliferative and anticoagulant activities.

Human smooth muscle cells were used to investigate the antiproliferative activities of sulfated carbohydrates. The antiproliferative potencies of coarse heparin fractions prepared by ultrafiltration increased with the mean molecular-weight, whereas the anticoagulant activities of a high-molecular-weight fraction had submaximal values. Furthermore, the dependence of antiproliferative activity on sulfate content is discussed. Carboxyl-reduction of heparin abolished both antiproliferative and anticoagulant activities. Sulfation of this compound yielded CRS-heparin with restored antiproliferative potency but devoid of antithrombin III-mediated anticoagulant activity. Sulfation of the pseudo-nonasaccharide, Trestatin A, yielded a compound having the highest antiproliferative activity, so far observed for a low-molecular-weight compound, and having only weak anticoagulant properties.

Inhibition of autoimmune deterioration in MRL/lpr mice by vitamin E.

The potential of the antioxidant vitamin E to modulate the progress of the SLE-like (systemic lupus erythematosus) autoimmune disease in MRL/MP-lpr/lpr (MRL/lpr) mice is described. Mice were orally supplemented with 0.4 mg vitamin E per day 5 times per week from week 8 of age onwards and compared with mice on a commercial or a vitamin E-deficient diet. Supplementation with vitamin E extended the mean survival time from 157 to 196 days; the massive spleen and lymph node enlargements were reduced; mitogenic responses of B and T cells were normalized; the abnormal differentiation patterns of thymic and splenic cell sub-populations were changed; titers of anti-double stranded DNA antibodies, concentrations of serum amyloid P component (SAP, an acute phase protein), and proteinuria were reduced. The results indicate that vitamin E beneficially affects the development of the SLE-like disease in MRL/lpr mice suggesting a possible measure to reduce human SLE and probably various other autoimmune diseases in humans as well.

Vitamin nutritional status and immunocompetence of elderly in Perugia (Italy): an epidemiological approach.

The influence of the vitamin nutritional status on the immunocompetence of a group of elderly people in the city of Perugia has been investigated. The impairment of some immunological (humoral as well as innate and acquired cell-mediated) functions seemed to be mostly related to age. Statistically significant correlations between the complement component C4 and plasma levels of retinol as well as alpha-tocopherol and an inverse correlation between titers of IgG and plasma retinol have been observed (significance level alpha = 5%).

Purification and characterization of DNA polymerases from the plasmacytoma MOPC 104E and Abelson murine leukemia viruses.

RNA-dependent DNA polymerases of intracisternal A particles from the mouse plasma cell tumor MOPC 104E and of Abelson murine leukemia virus (A-MuLV) were isolated from particle preparations by Nonidet P40 and ultrasonic treatment and purified by column chromatography on DEAE-cellulose and phosphocellulose, followed by centrifugation in linear sucrose gradients. Both DNA polymerases were very similar in their elution patterns from phospho and DEAE-cellulose, template specificities, requirements for optimum activity and inactivation by anti-(reverse transcriptase) antiserum. They are associated with ribonuclease H activity. For molecular weight determinations, antibody-precipitated enzymes were bound to staphylococcal-protein-A-Sepharose, solubilized and run on dodecylsulfate/polyacrylamide gels. Their apparent molecular weight was estimated to be 80000.

DNA polymerases from intracisternal A-type particles on the mouse plasmacytoma MPC 11.

Intracisternal A particles from mouse plasma cell tumors were isolated from microsomal vesiclels by detergent treatment and separated in linear sucrose gradients. Four peaks of DNA polymerase activities banding at densities of 1.30, 1.24, 1.20--1.22 and 1.13 g/cm3 were observed assaying on poly(rA).oligo(dT). Solubolized DNA polymerases of the 1.30 g/cm3...

RNA-dependent DNA polymerase from a cell line derived from the bone marrow of a patient with polycythemia vera.

A RNA-dependent DNA polymerase was isolated from a human cell line derived from the bone marrow of a patient with polycythemia vera. The purification procedure included chromatography on phosphocellulose and oligo(dT)-cellulose, and glycerol gradient centrifugation. The enzyme could be distinguished from polymerase A by salt elution from phosphocellulose, utilization of poly(rC) - oligo(dG) and its molecular size of about 70000, as determined by centrifugation. Throughout the purification procedure ribonuclease H activity was co-purified. Upon dodecylsulfate-polyacrylamide electrophoresis on microgradient gels two main bands with molecular weights of 68000 and 66000 and three minor bands were detected. The enzyme preferentially used poly(rA) - oligo(dT) as template-primer compared with poly(dA) - oligo(dT). It incorporated dGMP into polymer on poly(rC) - oligo(dG).