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Biomedical subjects

J Doskocil

Publications and source records attributed to J Doskocil.

At least 37 records · Page 2Linked to original sources
PubMed1978

Results of a five-year study of the curative effect of double stranded ribonucleic acid in viral dermatoses and eye diseases.

Double stranded RNA obtained from non-permissive E. coli cells infected with f2-phage was tested in 5 hospitals in viral dermtoses such as herpes simplex recidivans, herpes zoster, male genikeratonconjunctivitis herpetica and conjunctivitis lignosa. The results of clinical tests indicate that the preparation of phage double stranded RNA applied topically is harmless for man and has, in the majority of cases, a beneficial effect in the disease. This conclusion was based on the judgment of physicians, opinion of patients expressed in a questionnaire, and, results of a double-blind experiment.

Clinical Trials as Topic↗
PubMed1977

Purification of mouse cell interferon induced by isotopically labelled double-stranded f2 phage RNA.

The dynamics of interferon formation by an established cell line of mouse fibroblast (L cells) and by mouse peritoneal leukocytes induced by double-stranded RNA extracted from E. coli f2 phage is described. The L cells produced interferon at a lower rate, the maximum values were obtained at 12 to 20 hours after induction, and the production was ultimately dependent on the established cell line used and on the presence of DEAE-dextran during induction. The mouse peritoneal leukocytes (MPL), on the other hand, did not require DEAE-dextran and the maximum of interferon production was reached between 6 and 12 hours after induction. Both the L cell- and the MPL-interferons were purified and concentrated so that the final specific biologic activity was 100-to 300-fold higher than that of the initial preparations (1 to 5 X 10(6) interferon units per mg protein). Polyacrylamide gel electrophoresis showed similar migration profiles for the preparations of both interferons. The smaller part of the activity was situated in a broader, slow-moving peak and the greater part formed a sharp, high and fast-moving peak. Using 3H uridine-labelled f2 ds-RNA for induction of interferon it was found that one of the radioactivity zones coincided with the fast-moving activity peak of the purified and concentrated interferon.

Animals↗
PubMed1976

The role of thiol groups in nucleoside transport.

(1) The inactivation of various forms of nucleoside transport with reagents blocking thiol groups was studied in whole cells of E. coli B. No positive correlation between the efficiency of active transport and the extent or rate of inactivation could be demonstrated. (2) The most efficient constitutive nucleoside-transporting system was found to comprise a specific thiol component characterized by low rate of inactivation with N-ethylmaleimide; the less efficient inducible transport and the facilitated diffusion of guanosine require the integrity of another thiol component which is rapidly inactivated with N-ethylmaleimide. (3) The constitutive nucleoside-transporting system is completely inactivated with T4 phage, while other modes of nucleoside transport are much less affected. (4) Inactivation of constitutive transporting system in cells exposed to N-ethylmaleimide for a limited period of time continues long after the inhibitor has been removed, indicating storage of the inhibitor in some cellular compartment. Addition of dithiothreitol stops the inactivation immediately.

Arsenates↗
PubMed1976

Basic polypeptides as histone models. Effect of conformation, base composition and methylation of nucleic acids on the interaction with H1 and histone models and on the circular dichroism of complexes.

Interaction of histone H 1 and models simulating histone chains was followed by monitoring the melting curves of supernatants after the sedimentation of aggregated complexes. In a mixture of two DNAs the histones reacted selectively with (A+T)-rich and non-methylated DNA, respectively. H 1 and (Ala-Lys-Pro)n also interacted preferentially with DNA in a mixture with double stranded RNA whereas (Lys30,Ala70)n did not show any selectivity. (G+C)-rich DNA in complexes showed CD spectra the intensity of which decreased with increasing DNA methylation to values comparable with these of complexes of (A+T)-rich DNA. In complexed with double stranded RNA only the polymer (Lys30,Ala70) displayed CD pattern similar to spectra of complexes with DNA. It was concluded that formation and structure of complexes depend selectively on the DNA conformation and base composition.

Binding Sites↗
PubMed1976

A compact form of double-stranded RNA in solutions containing poly(ethyleneglycol).

Molecules of single-stranded ribosomal RNA and double-stranded replicative form of phage f2 RNA (dsRNA) adopt a compact form in solutions, containing sufficiently high concentrations of salt (NaCl) and polymer (PEG). However, only in the cases of native dsRNA molecules the compact particles are characterized by a regular internal structure, which accounts for the appearance of an intense positive band in CD spectra. Heating or acidification of PEG-containing solutions of dsRNA leads to the disappearance of the intense positive CD band, which results from the "destruction" of the regular internal structure of compact particles. Comparison of properties of DNA and dsRNA compact particles formed in PEG-containing water-salt solutions suggests the existence of similar mechanisms of compactization of double-stranded polynucleotides.

Circular Dichroism↗
PubMed1975

Inactivation of hapten-modified bacteriophage by antibody: increased sensitivity of the assay in media containing polyethylene glycol.

Inactivation of dinitrophenylated bacteriophage T4 by porcine and rabbit anti-dinitrophenyl (DNP) antibodies was studied by the complex inactivation methods. The inactivation titers increased 20-30 times when polyethylene glycol, mol. wt. 6000, was added to the incubation media. Consequently, the detection of dinitrophenylated serum albumin with the modified bacteriophage could be carried out with higher sensitivity upon addition of polyethylene glycol.

Antibodies↗
PubMed1975

Prevention of spontaneous autoimmunity to DNA in NZB/Swiss mice by treatment with natural double-stranded RNA.

Data are presented demonstrating the prevention of spontaneous autoimmune disease in NZB/Swiss mice treated natural double-stranded RNA. The successful treatment of animals was followed both by improvement in clinical manifestations and by the migration inhibition test performed with DNA as antigen. The reasons for the successful employment of natural double-stranded RNA are thought to be in its physicochemical properties.

Animals↗