We report a synthetic procedure for conversion of oligonucleotides to their 5'-triphosphate derivatives with moderate yield. The oligonucleotides were synthesized on solid support using standard phosphoramidite protocols. The DMT protection group was removed and the 5'-OH was phosphitylated using 2-chloro-4H-1,3,2-benzodioxaphosphorin-4-one followed by reaction with tributyammonium pyrophosphate and iodine oxidation. After subsequent removal from support and complete deprotection, the products were isolated by anion-exchange HPLC chromatography. Structures of several 5'-triphosphate derivatives have been proven by phosphorus NMR, Mass-spectrometry and by HPLC comparison with authentic samples.

Chromatography, High Pressure Liquid↗

PubMedDate not supplied

[Acidity and interaction with superoxide anion radical of echinochrome and its structural analogs].

Weak acid properties, autoxidation and interaction of natural polyhydroxy1,4-naphthoquinones (PHNQ) with superoxide anion-radical (O2-.) were studied by methods of potentiometric titration, polarography, and UV- and visible spectrophotometry. Sea urchin pigments 3-acetyl-2,6,7-trihydroxynaphthazarin (spinochrome C), 2,3,6,7-trihydroxynaphthazarin (spinochrome D), 2,3,6,7-trihydroxynaphthazarin (spinochrome E), 6-ethyl-2,3,7-trihydroxynaphthazarin (echinochrome A), synthetic 2,3-dihydroxy-6,7-dimethylnaphthazarin and 6-ethyl-2,3,7-trimethoxynaphthazarin (trimethoxyechinochrome A) were tested. Determined dissociation constants (pKi) were in the range of pH 5.3-8.5 (40% ethanol solvent). PHNQ autoxidation observrd in basic pH were inhibited by superoxide dismutase. Xanthine and xanthine oxidase was applied for O2-. generation. Interaction with O2-. led to sufficient time-dependent changing in spectra of echinochrome A, spinochromes D and E. There was weak O2-. influence on spinochrome C spectrum and no changing in trimethoxyechinochrome A spectrum. The spectra, that were transforming during time of reaction, contained pronounced isobestic point. It means formation the single reaction product. We proposed formation of 1,2,3,4-tetraketones from 2,3,5,8-tetrahydroxy-1,4-naphthoquinones (echinochrome A, spinochromes D and E) due to O2-.-induced oxidation of their OH-groups in 2 and 3 positions. Reaction constants were determined by competition method using nitro blue tetrazolium (NBT). The reaction constants were about 10(4)-10(5) M-1s-1. They were decreased in the order: echinochrome A > spinochrome D > spinochrome C > NBT > trimethoxyechinochrome A. Thus, we concluded that some of the natural PGNQ, containing hydroxyl groups in 2nd and 3rd positions, could operate as powerful superoxide anion-radical scavengers.

Antioxidants↗

PubMedDate not supplied

[Effect of antioxidant histochrome preparation on the contractile function and metabolism of the isolated rat heart under conditions of "calcium paradox", ischemia, and reperfusion].

A comparative study of protective effect of a new antioxidant histochrome on isolated rat heart at calcium paradox and ischemia-reperfusion was carried out. Perfusion with Ca-containing solution after 10-min perfusion with Ca-free medium caused depletion of high energy phosphates, loss of myoglobin, uncoupling of mitochondria, increase of left ventricular diastolic pressure. Pretreatment with histochrome led to decrease of cardiomyocyte damage evaluated by myoglobin efflux in perfused solution, attenuation of decrease ATP and phosphocreatine, and coupling of mitochondria. This resulted in a decrease of left ventricular diastolic pressure at calcium paradox. Less effect of histochrome treatment was noted in the case of ischemia-reperfusion model. It was concluded that histochrome effectively prevents heart from abnormalities caused by calcium imbalance in heart.

Adenine Nucleotides↗

PubMedDate not supplied

[Antioxidants, lipid peroxidation, and receptor-dependent increase in Ca2+ concentration in human platelets].

Content of tocopherol and total antiradical activity of hydrophobic antioxidants were estimated in human blood platelets. Two hydrophobic antioxidants--tocopherol and ubiquinone were detected in hexane extracts of thrombocytes using thin-layer chromatography. After incubation of thrombocytes with N-ethyl maleimide content of malonyl dialdehyde was increased and of tocopherol--decreased, receptor-dependent increase of Ca2+ concentration in cytoplasm was potentiated, while the Ca(2+)-blocking effect of nitroglycerol was decreased. Nitroglycerol did not inhibit the N-ethyl maleimide effect on content of malonyl dialdehyde in blood platelets. Addition of exogenous vitamin E to thrombocytes did not affect the receptor-dependent increase of Ca2+ concentration. Ascorbic acid inhibited the receptor-dependent increase of Ca2+ concentration. The data obtained suggest that nitrates may be used more rationally in combination with antioxidants and/or inhibitors of cyclooxygenase.

Antioxidants↗

PubMedDate not supplied

[The role of computer methods in the diagnosis of mono- and multifactorial traumatic compression of the brain].

A scheme of differential diagnosis of mono- and multifactor compression of the brain was formed on the grounds of 18 most frequently encountered signs of the injury. The work is based on 693 cases which were verified on operation. The results were checked on a large independent selection. Accuracy of recognition was 87.5%. The Table suggested by the authors may prove valuable in emergency situations when the patients are admitted in a serious condition, in impetuous development of the compression syndrome, and when there is lack of time for carrying out instrumental examination.

Adult↗

PubMedDate not supplied

[Luminescence, induced by UV-irradiation, of intact human skin].

UV-C induced chemiluminescence of human skin was investigated in vivo by means of an image-producing system using photon-counting camera and computer PERICOLOR-1000. Luminescence after UV-C application is shown to decline nonexponentially, the parameters of the decline depending on irradiation dose, skin specimen and previous irradiations. If the same skin specimen is irradiated second time 3-36 hours after the first irradiation, the luminescence decline time increases from one-two minutes to more than half an hour. During the time when the decline is slow the images produced by irradiation through the diaphragm do not sustain distinct contours due to the luminescence of nonirradiated skin. The luminescence is shown to be under the organisms' control and to diminish significantly after the application of acetylsalicylic acid.

Aspirin↗

PubMedDate not supplied

[Antioxidant properties of benzofurocaine, phenycaberan and orthophen].

The antioxidant properties of benzofurocaine, phenycaberan, crithophen, alpha-tocopherol and ionol were evaluated by inhibition of oxygen absorption by liposomes from egg phosphatidylcholine induced by the addition of an prooxidant. The activity of the tested agents at inhibition of Fe2+-ascorbater-initiated oxidation decreases in the order: ionol, benzofurocaine, phenycaberan, orthophen, alpha-tocopherol; emine-initiated (EDTA-independent) oxidation of phosphatidylcholine is inhibited only by ionol, orthophen and alpha-tocopherol. Phenycaberan exerts no effect on oxidation and benzofurocaine increases the rate of emine-initiated absorption of oxygen. Thus, benzofurocaine, phenycaberan and orthophen may be referred to as selective inhibitors of Fe2+-initiated peroxidation of phosphatidylcholine.

Anesthetics, Local↗

PubMedDate not supplied

[Diastereomers of nonionic analogs of nucleic acids. V. Alkylation of nucleic acids in the living cells by ethylated derivatives of oligonucleotides containing the residue of nitrous yperite. The effect of the phosphotriester fragment configuration].

The alkylation of the cell biopolymers (RNA, DNA, proteins) by reagents Tp'(Et)Tp'(Et)Tp'(Et)TpU(CHRCl) (1) Tp'(Et)Tp''(Et)Tp'(Et)TpU(CHRCl) (2) Tp''(Et)Tp'(Et)Tp''(Et)TpU(CHRCl) (3) Tp''(Et)Tp''(Et)Tp''(Et)TpU(CHRCl) (4) Tp(Et)Tp(Et)Tp(Et)TpU(CHRCl) (5) Tp(Et)Tp(Et)Tp(Et)Tp(Et)U(CHRCl) (6) TpTpTpTpU(CHRCl) (7) where (CHRCl) is the residue of 2',3'-O-[4-N-(2-chloroethyl)-N-methylamino]-benzylidene has been investigated in the case of the ascite carcinoma Krebs-2. p' and p" designate the enantiomeric configurations at the internucleotide phosphorus atoms of the triester fragment--Tp(Et)T--, and p designates the racemic mixture. Completely and partly ethylated reagents (1)-(6) have been found to bind to the cells 4-15 fold more effectively than the diester derivative. The concentration of reagents (1)-(6) in the cells is 2-7 fold higher than in the external medium. Among the diastereomers (1)-(4) reagent (4) with the p"-configuration is the most efficient in binding with the cells 2-3 fold more efficient than reagents (1)-(3). The main targents of modifications performed in the cells by means of reagents (1)-(7) have been established. These are RNA, DNA and proteins. The share of the reagents which react with nucleic acids increases from 45% [reagent (1)] to 80% [reagent (4)], and that reacting with proteins decreases from 50 to 20% correspondingly. Reagent (4) with the p" configurations at phosphotriester fragments alkylates nucleic acids most effectively among the phosphotriester diastereomers (1)-(4): 11-fold more efficient than reagent (1) with configuration p'. The extent of modification of poly(A)+-tracts of m-RNA by reagent (4) in comparison with reagent (1) is 50-fold higher.

Alkylation↗

PubMedDate not supplied