[Optimization of artificial respiration parameters in patients with acute pulmonary parenchymal damage syndrome]. / Optimizatsiia parametrov IVL u bol'nykh s sindromom ostrogo parenkhimatozhnogo povrezhedeniia legkikh.

The relationship between the mean pressure in the trachea, generated in mechanical ventilation of the lungs (Ptr.m), and normal arterial oxygenation is linear in ventilated patients with severe bilateral acute parenchymatous damage to the lungs. Under conditions of mechanical ventilation of the lungs (MVL) with regulated volume, constant end-expiratory pressure (PEEP) and inspiratory pause (eIP) are effective methods for regulating Ptr.m. However, the efficacy of regulating Ptr.m by PEEP and IF for each clinical case is different. The algorithm of using PEEP and IF for optimizing the respiratory pattern in this category of patients is not clear, too. The results indicate that optimization of MVL with controlled volume should be started with selecting the optimal level of PEEP for each patient. The level of Ptr.m should not be increased immediately at by of prolonging eIP, because the probability of compromising the hemodynamics is higher in such a case than the probability of improving blood oxygenation. Only after selecting the optimal PEEP is it permissible to try to improve arterial oxygenation by prolonging xx, because under such conditions the efficacy of prolonged inspiration is notably increased. Our data indicate that eIP no higher than 30% of the respiratory cycle (inspiration/expiration = 1.5/1) is the optimal. A further increase of eIP gives rise to a tendency towards decrease of arterial oxygenation and oxygen transport to tissues.

[Phosphorus-containing inhibitors of penicillin acylase. 4. Irreversible inhibition of penicillin acylase from Escherichia coli by monoaryl esters of benzylphosphonic acid]. / Fosfor-soderzhashchie ingibitory penitsillinatsilazy. 4. Neobratimoe ingibirovanie penitsillinatsilazy iz Escherichia coli monoarilovymi éfirami benzilfosfonovoi kisloty.

Monoaryl of benzylphosphonic acid have been synthesized and studied as the inhibitors of penicillin acylase. These compounds were found to be effective and selective irreversible inhibitors of the enzyme. The kinetic parameters of enzyme inactivation are determined, and possible mechanism of the inhibition is discussed. These phosphonates should be useful as both penicillin acylase active site titrants and the tools for the enzyme function study. Benzylchloromethyl keton has been also prepared and it is an irreversible inhibitor of penicillin acylase.

Anti-inflammatory properties and inhibition of leukotriene C4 biosynthesis in vitro by flavonoid baicalein from Scutellaria baicalensis georgy roots.

Anti-inflammatory activity of baicalein (5,6,7-trioxyflavone-7-O-beta-D-glucuronide) was greater in the chronic inflammation model (rat adjuvant arthritis, ED50 = 120.6 mg/kg) than observed in the rat carrageenan-induced paw edema, ED50 > or = 200.0 mg/kg. A comparative study of the 5-lipoxygenase (5-LO) inhibitory activity of baicalein, BW 755 C, and hydroxamic acid arachidonate on leukotriene C4 (LTC4) biosynthesis by rat resident peritoneal macrophages stimulated with calcium ionophore (A 23186) showed that these drugs significantly inhibited LTC4 production, IC50: 9.5, 41.8, and 2.8 microM, respectively. This finding suggests that inhibition of the 5-LO pathway of arachidonic acid metabolism may be one of the mechanisms of baicalein's anti-inflammatory activity.

Ligand-exchange chromatography of alpha-trifluoromethyl-alpha-amino acids on chiral sorbents.

The chromatographic behaviour of some alpha-trifluoromethyl-alpha-aminoacids on L-proline- and L-hydroxyproline sorbents was studied. The retention and selectivity parameters of the separation of amino acid enantiomers on the sorbents were determined. The introduction of a CF3 [corrected] group led to an increased selectivity in the separation of amino acid enantiomers on a proline sorbent and to a decreased selectivity on a hydroxyproline sorbent.

[High performance liquid chromatography of leukotriene C4 on the aminopropyl sorbent]. / Vysokoéffektivnaia zhidkostnaia khromatografiia leikotriena C4 na aminopropil'nom sorbente.

Chromatographic behaviour of leukotriene C4, its methyl ester and hydrophobic side products of their synthesis on an aminopropyl sorbent has been investigated, the retention time values being determined by both hydrophobic and ionic interaction of the substances with the sorbent. Optimal conditions of the separation are determined.

Optimization of reversed-phase separation of some nucleosides.

Optimization of the separation of ionogenic nucleosides in reversed-phase high-performance liquid chromatography can be based on the solvophobic theory of retention. The dependence of the capacity factors, selectivity, plate number and resolution on the pH may be calculated by knowing pK(a) and measuring the capacity factors for the compounds in the ionized and molecular forms. An increase in the eluent ionic strength (I) results in increased selectivity.

[Reverse phase high performance liquid chromatography in the synthesis of leukotrienes A4 and C4]. / Obrashchenno-fazovaia vysokoéffektivnaia zhidkostnaia khromatografiia v sinteze leikotrienov A4 i C4.

The chromatographic (RP HPLC) behaviour of leukotriene C4, its methyl ester, leukotriene A4 methyl ester and some chemicals involved in their synthesis have been investigated. Optimal conditions of separation were determined for the gradient and isocratic HPLC. Parameters of the interaction of the substances with hydrophobic surface are discussed in terms of solvophobic theory.

Reversed-phase high-performance liquid chromatography of pyrimidine bases and nucleosides. Application of solvophobic theory.

The chromatographic behaviour of some natural and modified pyrimidine bases and nucleosides on an octadecyl stationary phase was studied. The retention and selectivity parameters of the separation of the compounds studied were derived on the basis of solvophobic theory. The mechanism of base and nucleoside interactions with the surface of the hydrocarbonaceous stationary phase is discussed. The best separation is observed at pH 3.5 for the bases and at pH 4.8-5.2 for the nucleosides. An increase in the solute surface tension results in an increased selectivity of separation. When the surface tension and the ionic strength of the mobile phase are not kept constant, there are considerable deviations in retention from that predicted by solvophobic theory.

[Pharmacokinetic characteristics of 6-azacytidine]. / Osobennosti farmakokinetiki 6-azatsitidina.

Pharmacokinetics of 6-azacytidine, an antitumour drug, is studied by ion-pair reversed-phase highly effective liquid chromatography. The survey of the drug elimination from blood is of a two-phase character: the first phase--with a biological half-life of 5.5 min (for rats) and 6.5 min (for rabbits); the second phase--1.2 and 2.5 h, respectively. For a 24 h period 75% of the drug is excreted unchanged in the urine.

[Pharmacokinetics of ethonium administered perorally]. / Farmakokinetika étoniia pri peroral'nom vvedenii.

In experiments on rats it was shown that ethonium pharmacokinetics at intragastric administration may be described within the framework of the two-compartment model with absorption. After administration ethonium cannot be directly absorbed although its absorption proceeds rapidly. The distribution between the central and peripheral compartments is slowed as well as the process of elimination from the blood flow.