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  • 1
    Language: English
    In: Current Signal Transduction Therapy, 2011, Vol.6(3), p.363-382
    Description: The animal ribonucleases and plant nucleases are selective cytotoxic enzymes with several biological activities inclusively also with antitumorous effects. The first attention from animal researches is dated to 1938 year, meanwhile plant enzyme investigators awoke their attention in last time. The bovine pancreatic ribonuclease, after the first structurally studies, allured very soon the peoples with functionally interests. The results of studies directed to antitumor effect were firstly very weak. The latter isolated bovine seminal ribonuclease was more effective from this aspect. Also human pancreatic ribonuclease stimulated interest about its antitumor activity what was realized by its dimerization and other molecular studies. Ribonuclease inhibitors have been very limited substances in the cytotoxicity of antitumor effectivity. On the other side a conjugation of cytostatic enzymes with polymers enhanced the antitumor activity of them and lowered their toxicity. 〈/p〉〈p〉 Plants as producers of new engineered pharmaceuticals are becoming a very attractive tool to improve human health. In last years the main attention from the plant antitumor effects begun to devote to plant ribonucleases and mainly nucleases I. These nucleases, major plant sugar non-specific endonucleases form rather heterogenous group of catalytically related enzymes. An important property that suggests intimate heterogeneity within the nuclease group is the specificity towards secondary structures of nucleic acids and the ability to cleave different homopolymers. 〈/p〉〈p〉 Angiogenin, as RNase initiates vascularization of tumors and subsequent tumor growth. The new substances against angiogenin and its process angiogenesis are now in the centrum of antitumor-effort. 〈/p〉〈p〉 The combination of these three main substances – ribonuclease, nucleases and antiangiogenins seems to be perspective for further studies. The preliminary results with some of them (bovine pancreatic RNase A, or bovine seminal BS-RNase with tomato recombinant nuclease and antiangiogenesis neamine, hyaluronidase, and melatonin is our first step.
    Keywords: Angiogenin ; Anticancer ; Antiproliferative ; Cytotoxic ; Effect ; Human ; Nuclease ; Plant ; Ribonuclease ; Cell ; Therapy ; Traumatic ; Brain ; Injury ; Adult ; Pediatric ; Primary ; Secondary ; Angiogenesis ; Neurogenesis ; Functional ; Recovery ; Endogenuis ; Exogenius ; Factors ; Dedifferentiation ; Pluripotent ; Multipotent ; Proliferation ; Survival ; Precursor Cells
    ISSN: 1574-3624
    E-ISSN: 1574-3624
    Source: Bentham Science Publishers
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  • 2
    Language: English
    In: Recent Patents on DNA & Gene Sequences, 2010, Vol.4(1), p.29-39
    Description: The antiproliferative and antitumor effect of leaf ribonuclease was tested in vitro on the human ML-2 tumor cell line and in vivo on athymic nude mice bearing human melanoma tumors. The antiproliferative activity of this plant ribonuclease in vitro studies was negligible. In the experiments in vivo a significant decrease of the tumor size, however was observed. From nucleases the mung bean nuclease (PhA) was studied first from nucleases. The antitumor effect of this enzyme on ML2 human tumor cell line was almost non-effective. However, significant antitumor activity was detected on human melanoma tumors in vivo. The antitumor effect of black pine pollen nuclease (PN) tested in vitro was also negligible. On the other side, in the experiments in vivo a significant decrease of the human melanoma tumor size was observed too. Recombinant plant nucleases of tomato (TBN1) and hop (HBN1) (submitted to patenting under no. PV 2008-384;Z7585) were isolated to homogeneity and examined for their antitumor effects and cytotoxicity. Although antiproliferative effects of both recombinant nucleases were not significant on the ML-2 cell culture in vitro, the nucleases were strongly cytostatic in vivo after their administration intravenously as stabilized conjugates with polyethylene glycol (PEG). Recombinant both nucleases were as effective against human melanoma tumors as previously studied pine pollen (PN) and mung bean nucleases and their effects were reached at about ten times lower concentrations compared to the use of bovine seminal RNase (BS-RNase).
    Keywords: Anticancer ; Antiproliferative Cytotoxic ; Effect Human ; Nuclease ; Plant Ribonuclease
    ISSN: 1872-2156
    E-ISSN: 2212-3431
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  • 3
    Language: English
    In: Journal of Photochemistry & Photobiology, A: Chemistry, 15 February 2016, Vol.317, pp.72-80
    Description: The paper presents results of the investigation of photocatalytic activity of coatings of nanoparticles of titania applied on glass slides and silica optical fiber using side excitation of the slides and fibers and direct launching of the excitation light into the fiber input face. Titania nanoparticle coatings were prepared by the alkoxide sol–gel method from titanium isopropoxide and from dispersion of anatase nanoparticles Aeroxide P25 in water. The dip-coating technique was used for the application of the sols onto slides and fibers and a coating die for the continuous application of a sol during fiber drawing. Kinetics of decomposition of methylene blue and methyl orange solutions in water was employed to characterize the photocatalytic activity of the coatings. The measured kinetic data were fitted by a model of 1st order reaction. The 1st order rate constant related to the catalyst amount, a relative 1st order rate constant, was employed for evaluating the photocatalytic activity. It has been found that coatings fabricated from the nanoparticle dispersion are more active than those obtained by the alkoxide method. In the case of methylene blue, a value of the relative 1st order rate constant of about 1.55 ± 0.13 min g was obtained for coatings on slides and fibers which is practically independent of the excitation way.
    Keywords: Photocatalysis ; Tio2 Nanoparticle ; Optical Fiber ; Glass Slide ; Kinetics ; Decomposition ; Methylorange ; Methyleneblue ; Visual Arts ; Chemistry
    ISSN: 1010-6030
    E-ISSN: 1873-2666
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  • 4
    Language: English
    In: Journal of Sol-Gel Science and Technology, 2017, Vol.81(3), pp.867-879
    Description: To access, purchase, authenticate, or subscribe to the full-text of this article, please visit this link: http://dx.doi.org/10.1007/s10971-016-4222-x Byline: Ivo Barton (1,2), Vlastimil Matejec (1), Jan Mrazek (1), Ondrej Podrazky (1), Josef Matousek (2) Keywords: Multilayered coatings; Silica and titania layers; Alkoxide sol--gel method; Silica fiber; Silica capillary Transmission characteristics Abstract: Abstract The paper presents results on sol--gel preparation and characterization of multilayered coatings, Bragg mirrors, on silica slides, silica fibers, and inner walls of silica capillaries. In the coatings titania was employed for high-index layers and silica for low-index ones. Coatings with up to three pairs of titania and silica layers have been fabricated from alkoxide input sols. A sol based on tetramethylorthosilicate with RW=1.75 and tetramethylorthosilicate concentration of 2mol/l for used for silica layers. A sol of titanium butoxide with RW and alkoxide concentration of 1.58 and 0.315mol/l, respectively, was employed for titania layers. Modified dip-coating techniques have been developed for the application of gel layers from the sols onto fibers or inside silica capillaries. Single gel layers were dried at 200[degrees]C, final coatings were heat-treated at 450[degrees]C. Relative velocities of substrates and sols have been controlled to obtain layers with an optical thickness of about 140nm. Prepared single layers have been characterized by measuring their thicknesses by optical profilometry and refractive indices of titania layers by spectral ellipsometry. Homogeneity and appearance of multilayered coatings have been characterized by scanning electron microscopy and morphology of coatings by X-ray spectrometry. Optical properties of coatings on silica slides have been determined from their UV--VIS-NIR transmission and reflection spectra. Transmission optical properties of coated optical fibers and capillaries have been characterized by angular distributions of the output power from the fibers at a wavelength of 650nm and by measuring their transmission spectra. Obtained results show that Bragg mirrors fabricated on silica slides can exhibit a minimal transmittance of about 17% around a wavelength of 650nm and that prepared fibers and capillaries provided with Bragg-mirror coatings are capable of guiding light and have lowest transmission losses around a wavelength of 550nm. Graphical Abstract Author Affiliation: (1) Institute of Photonics and Electronics of CAS, v.v.i. Chaberska 57, Prague, 18251, Czech Republic (2) Department of Glass and Ceramics Technicka 5, University of Chemistry and Technology, Prague, 166 28, Czech Republic Article History: Registration Date: 27/09/2016 Received Date: 16/06/2016 Accepted Date: 27/09/2016 Online Date: 17/10/2016
    Keywords: Multilayered coatings ; Silica and titania layers ; Alkoxide sol–gel method ; Silica fiber ; Silica capillary Transmission characteristics
    ISSN: 0928-0707
    E-ISSN: 1573-4846
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  • 5
    Language: English
    In: Oncology research, 2009, Vol.18(4), pp.163-71
    Description: Recombinant plant nucleases R-TBN1 and R-HBN1 were isolated to homogeneity and examined for their antitumor effects and cytotoxicity. Although antiproliferative effects of both recombinant nucleases were not significant on the ML-2 cell culture in vitro, the nucleases were strongly cytostatic in vivo after their administration intravenously as stabilized conjugates with polyethylene glycol (PEG). Recombinant nucleases were as effective against melanoma tumors as previously studied pine pollen (PN) and mung bean nucleases and their effects were reached at about 10 times lower concentrations compared to the use of bovine seminal RNase (BS-RNase). Because the recombinant nucleases R-HBN1 and R-TBN1 share only 67.4% amino acid identity and showed only partial immunochemical cross-reactivity, their similar anticancerogenic effects can be mainly explained by their catalytical similarity. Both recombinant nucleases showed lower degree of aspermatogenesis compared to BS-RNAse and PN nuclease. Unlike BS-RNase, aspermatogenesis induced by both recombinant nucleases could not be prevented by the homologous antibody complexes. Owing to relatively low cytotoxicity on the one hand, and high efficiency at low protein levels on the other, recombinant plant nucleases R-HBN1 and R-TBN1 appear to be stable biochemical agents that can be targeted as potential antitumor cytostatics.
    Keywords: Cell Proliferation ; Spermatogenesis ; Antineoplastic Agents -- Pharmacology ; Endonucleases -- Pharmacology ; Melanoma -- Prevention & Control ; Recombinant Proteins -- Pharmacology
    ISSN: 0965-0407
    E-ISSN: 15553906
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  • 6
    In: Proceedings of the National Academy of Sciences of the United States, July 6, 1999, Vol.96(14), p.7768(6)
    Description: Monomeric human pancreatic RNase, devoid of any biological activity other than its RNA degrading ability, was engineered into a dimeric protein with a cytotoxic action on mouse and human tumor cells, but lacking any appreciable toxicity on mouse and human normal cells. This dimeric variant of human pancreas RNase selectively sensitizes to apoptotic death cells derived from a human thyroid tumor. Because of its selectivity for tumor cells, and because of its human origin, this protein represents a potentially very attractive, novel tool for anticancer therapy.
    Keywords: Cell Mediated Cytotoxicity -- Research ; Ribonuclease -- Physiological Aspects ; Cancer ; Cytopathology
    ISSN: 0027-8424
    E-ISSN: 10916490
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  • 7
    Language: English
    In: Journal of Biological Chemistry, 12/29/1995, Vol.270(52), pp.31097-31102
    Description: Bovine seminal ribonuclease (BS-RNase), a dimeric homolog of bovine pancreatic ribonuclease A (RNase A), is toxic to mammalian cells. In contrast to dimeric BS-RNase, a monomeric BS-RNase and RNase A are not cytotoxic and are bound tightly by cytosolic ribonuclease inhibitor. To elucidate the mechanism of ribonuclease cytotoxicity, we constructed a series of hybrid and semisynthetic enzymes and examined their properties. In five hybrid enzymes, divergent residues in BS-RNase were replaced with the analogous residues of RNase A so as to diminish an interaction with a putative cellular receptor. In a semisynthetic enzyme, the disulfide bonds that cross-link the monomeric subunits of dimeric BS-RNase were replaced with thioether bonds, which can withstand the reducing environment of the cytosol. Each hybrid and semisynthetic enzyme had ribonucleolytic and cytotoxic activities comparable with those of wild-type BS-RNase. These results suggest that dimeric BS-RNase (pI = 10.3) enters cells by adsorptive rather than receptor-mediated endocytosis and then evades cytosolic ribonuclease inhibitor so as to degrade cellular RNA. This mechanism accounts for the need for a cytosolic ribonuclease inhibitor and for the cytotoxicity of other homologs of RNase A.
    Keywords: Chemistry ; Anatomy & Physiology;
    ISSN: 0021-9258
    E-ISSN: 1083-351X
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  • 8
    Language: English
    In: Journal of controlled release : official journal of the Controlled Release Society, 18 July 2002, Vol.82(1), pp.29-37
    Description: RNase A (bovine pancreatic ribonuclease) and BS-RNase (bovine seminal ribonuclease) are monomeric and dimeric enzymes, respectively, with aspermatogenic and antitumor activities. While the aspermatogenic and, in some experimental situations, the antitumor effects of the RNase A are only minor, the activity of BS-RNase in these phenomena is very significant. These differences can be annulled by means of conjugation of the enzymes with PEG (polyethylene glycol) chains. Aspermatogenic activity was studied histologically following subcutaneous injections of RNase A and BS-RNase conjugates in ICR mice, and the antitumor activity in athymic nude mice with growing human melanoma with i.p. injection of these conjugated ribonucleases. The experiments proved that RNase A, when conjugated to PEG, produced identical aspermatogenic and antitumour effects as BS-RNase conjugated to this polymer. Immunogenicity of RNase A and BS-RNase did not change substantially after the conjugation with PEG polymers. Binding of produced antibodies to both ribonucleases attached to PEG, however, was substantially reduced.
    Keywords: Antineoplastic Agents -- Pharmacology ; Antispermatogenic Agents -- Pharmacology ; Endoribonucleases -- Pharmacology ; Polyethylene Glycols -- Chemistry ; Ribonuclease, Pancreatic -- Pharmacology
    ISSN: 0168-3659
    E-ISSN: 18734995
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  • 9
    Language: English
    In: The Journal of biological chemistry, 27 June 2003, Vol.278(26), pp.23817-22
    Description: Dimers, trimers, and tetramers of bovine ribonuclease A, obtained by lyophilization of the enzyme from 40% acetic acid solutions, were purified and isolated by cation exchange chromatography. The two conformers constituting each aggregated species were assayed for their antitumor, aspermatogenic, or embryotoxic activities in comparison with monomeric RNase A and bovine seminal RNase, which is dimeric in nature. The antitumor action was tested in vitro on ML-2 (human myeloid leukemia) and HL-60 (human myeloid cell line) cells and in vivo on the growth of human non-pigmented melanoma (line UB900518) transplanted subcutaneously in nude mice. RNase A oligomers display a definite antitumor activity that increases as a function of the size of the oligomers. On ML-2 and HL-60 cells, dimers and trimers generally show a lower activity than bovine seminal RNase; the activity of tetramers, instead, is similar to or higher than that of the seminal enzyme. The growth of human melanoma in nude mice is inhibited by RNase A oligomers in the order dimers 〈 trimers 〈 tetramers. The action of the two tetramers is very strong, blocking almost completely the growth of melanoma. RNase A dimers, trimers, and tetramers display aspermatogenic effects similar to those of bovine seminal RNase, but, contrarily, they do not show any embryotoxic activity.
    Keywords: Antineoplastic Agents -- Pharmacology ; Peptide Fragments -- Pharmacology ; Ribonuclease, Pancreatic -- Chemistry
    ISSN: 0021-9258
    E-ISSN: 1083351X
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  • 10
    Language: English
    In: FEBS letters, 06 March 2007, Vol.581(5), pp.930-4
    Description: The hypothesis that the cytosolic RNase inhibitor (cRI) has a role in the protection of the cellular redox homeostasis was investigated testing the effects of oxidants and anti-oxidants on normal, primary endothelial HUVE cells, and malignant HeLa cells, before and after their engineering into cRI-deprived cells. We found that cRI plays an important, possibly a key, physiological role in the protection of cells from redox stress, as demonstrated by decreased GSH levels as well as increased oxidant-induced DNA damage in cRI deprived cells.
    Keywords: Carrier Proteins -- Metabolism ; Enzyme Inhibitors -- Metabolism ; Ribonucleases -- Antagonists & Inhibitors
    ISSN: 0014-5793
    E-ISSN: 18733468
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