[Mechanism of action of 2-aryloxy-2-thio-1,3,2-oxazaphosphorinane pesticides]. / Issledovanie mekhanizma deistviia pestitsidov riada 2-ariloksi-2-tio-1,3,2-oksazafosforinana.

The interaction of 2-aryloxy-2-thio-1,3,2-oxazaphosphorinanes exhibiting nematocide, insecticide/acaricide, and synergetic activities with monoamine oxidases and the interaction of the corresponding oxones, 2-aryloxy-2-oxo-1,3,2-oxazaphosphorinanes, with various cholinesterases, carboxyl esterases, and monoamine oxidases were studied. We showed that the thioderivatives inhibited monoamine oxidases, whereas oxones, which are, as a rule, weak cholinesterase inhibitors, strongly inhibited carboxyl esterases of the American cockroach and were transformed with monoamine oxidases into the strong cholinesterase inhibitors, acyclic phosphamidates. This allowed us to explain the low toxicity of the thioderivatives, the high toxicity of the oxoderivatives, and the great difference in toxicities of thio- and oxocompounds in the 1,3,2-oxazaphosphorinane series. The capacity of thioderivatives to inhibit monoamine oxidases and of oxoderivatives and their further activation products to inhibit carboxyl esterases, i.e., both enzymes responsible for pyrethroid detoxication in insects, explains the synergetic activity of the 1,3,2-oxazaphosphorinane series.

Dynamics of clot growth induced by thrombin diffusing into nonstirred citrate human plasma.

The dynamics of clot formation was studied in a two-compartment chamber designed to allow free diffusion of thrombin according to its concentration gradient into nonstirred citrate plasma or fibrinogen solution. Fibrin clots in fibrinogen solutions increased progressively until the substrate was depleted. In plasma, the clot weight dynamics significantly depended on the concentration of thrombin in the thrombin compartment. When the thrombin concentrations were extremely low (25-40 nM), the clot weight increased throughout the experiment (sometimes 20-24 h). At higher thrombin concentrations, the clot weight increased for 1-2 h and then stopped growing for the following 3-4 h. The clot weight observed at the plateau varied only slightly in the range of thrombin concentrations of 50-770 nM. In this range, high thrombin concentrations (250-770 nM) caused a second increase in the clot weight 4-8 h after the start of diffusion, which was followed by the second plateau in the curve of clot weight against time. The time to the plateau and the plateau duration decreased with increasing thrombin concentrations. The abundant plasma inhibitors of thrombin cannot account for these results. It was hypothesized that an as yet unknown mechanism is responsible for the inhibition of clot growth.

Spatiotemporal dynamics of clotting and pattern formation in human blood.

We examined the spatial dynamics of in vitro clot growth in human blood and plasma and found that initially, a clot grows at a constant speed, then abruptly stops and becomes surrounded by an 'inhibition zone' in which coagulation is strongly suppressed. We also observed the formation of 'stratified structures' (target patterns) in which solid layers alternated with liquid plasma. These and other spatial regimes of clotting are explained in terms of two interacting concentration waves propagating without attenuation. The experimental results are consistent with a hypothesis that blood is a bi-excitable medium, a new type of excitable medium.

[Spatial aspects of blood coagulation dynamics. III. Growth of clots in vitro]. / Prostranstvennye aspekty dinamiki svertyvaniia krovi. III. Rost tromba in vitro.

The growth of fibrin clots in thin blood plasma layers was studied. It was found that the clot growth stops or is strongly retarded if its thickness approaches 0.5 mm. Polymer clots growing toward each other fuse together at distances between the coagulation activation centers less than 1 mm, whereas at distances of about 1.5 mm, the clots are separated by ungrowing flat gaps. In some experiments, successive formation of concentric ring-shaped structures was observed. Around the centers of coagulation initiation, up to 3 fibrin rings separated by areas of uncoagulated plasma were formed. The data agree well with the hypothesis advanced by the authors earlier that blood coagulation is regulated by auto-wave mechanism.

[Mechanism of action of thiophosphoroorganic insectoacaricides containing fragments of N-carbaalkoxylated amino acids]. / Issledovanie mekhanizma deistviia tiofosfororganicheskikh insektoakaritsidov, soderzhashchikh fragmenty N-karbalkoksilirovannykh aminokislot.

Toxicity and insecticide and acaricide activity of compounds (1) is significantly dependent on the nature of amino acid (n = 1 or 2) and substituents in carbamate and amino acid ester groups (R and R1). Investigation of interaction of these compounds with mammalian carboxylesterases, and the appropriate "oxones" with choline esterases of mammal and arthropoda revealed that the lower toxicity and activity of beta-alanine derivatives (n = 2) compared with glycine derivatives (n = 1) are due to the more rapid hydrolysis by carboxylesterases (detoxication). The low toxicity of dithiophosphonate with R = Me, R1 = Bu(i), n = 1 and the high toxicity of its isomer with R = Bu(i), R1 = Me, n = 1 are associated with the more rapid oxidative cleavage of isobutyl group in comparison with the other substituents, because detoxication occurs by the cleavage of R1 and activation--by that of R respectively.

Calcium threshold in human plasma clotting kinetics.

In vitro clotting kinetics of citrate human blood plasma under its titration with calcium ions are studied. Contact activation (Factor XIa + plasma kallikrein) is shown to be independent of calcium while non-linear growth of thrombin concentration is demonstrated at calcium concentrations higher than 0.25 mM under conditions of contact activation caused by quartz walls of the measuring cell. Thrombin generation kinetics are well fitted with an exponential function. Power index of the exponential function steeply rises as calcium concentration increases from 0.25 to 0.5 mM and reaches plateau at higher concentrations. At free calcium concentrations under 0.25 mM thrombin level does not grow remaining lower than 30 pM. So, blood coagulation system behaves in a threshold manner under calcium concentration changes. The threshold concentration of free calcium is equal to 0.25 +/- 0.05 mM.

[Threshold behavior of the blood coagulation system upon changes in calcium concentration]. / Porogovoe povedenie sistemy svertyvaniia krovi pri izmenenii kontsentratsii kal'tsiia.

Dependence of the citrate human blood plasma clotting kinetics on free calcium concentration under its titration with calcium has been studied in vitro. Activation of factor XI is shown to be independent on calcium, while of thrombin concentration increases non-linearly at calcium concentrations in the range 0.2-0.3 mM. Kinetics of the thrombin generation fits well by the exponential function. Power indexes of the exponents rise steeply as calcium concentration increases from 0.2-0.5 mM and reach plateau at higher concentrations. At free calcium concentrations under 0.2 mM the thrombin level does not increase and remains lower than 10 pmol/ml as seen by our measuring system whose sensitivity threshold is surely less than 10 pmol/ml. Thus, the blood coagulation system behaves in a threshold manner under changes of calcium concentration. The threshold concentration of free calcium is equal to 0.2 mM.

[A filtration study of erythrocyte deformability]. / Filtratsionnoe issledovanie deformiruemosti éritrotsitov.

The study of two flow methods (constant flow method and initial flow rate method) has been conducted to specify and compare methodological approaches to quantitation of red cell deformability. Washed red cells were resuspended in saline medium with glucose and albumin and examined for deformability by the above methods under different conditions. The parameters are presented to characterize flow curves obtained with the constant flow method. The authors have established optimal conditions for the measurements: the composition of the medium, the suspension HCT, leukocyte number, filtrate types, etc. With meeting of the above methodological requirements, both the methods permit quantitation of red cells deformability and can be utilized for stored blood and erythrocyte mass quality control.

[Refractory effect and alloimmunization after transfusion of thrombocytes]. / Refrakternost' i alloimmunizatsiia pri perelivanii trombotsitov.

The authors discuss possible ways for prevention of alloimmunization with HLA-antigen in acute leukemia patients after platelet transfusions. Prevention or delay of HLA-alloimmunization is possible when platelets of single random donor are used instead of pooled random donor platelets for transfusions. The effect of leucocyte removal from platelet concentrates and ultraviolet irradiation of platelet concentrates under conditions of blood bank on alloimmunization and refractoriness incidence has been considered.

[Isolation of thrombocyte concentrates from the leuko-thrombocytic buffy coats of donor blood and their preservation]. / Vydelenie kontsentratov trombotsitov iz leikotrombotsitarnogo sloia donorskoi krovi i ikh konservirovanie.

A new method has been developed for platelet concentrate (PC) preparation from the whole blood buffy coats. This method makes possible obtaining leukocyte-poor PC as compared to that prepared from platelet rich plasma. Functional characteristics of PC stored in Soviet plastic bags at room temperature (22 degrees C) under continuous agitation at circular rotator were studied during 7 days. Satisfactory maintenance of functional activity was noted during 5 days of PC storage. The method of PC preparation from the whole blood buffy coats can be also used for manual plateletpheresis of a single donor.

[Development of the cerebellar glomeruli in the ontogeny of hens]. / Razvitie klubochkov mozzhechka v ontogeneze kur.

By means of light and electron microscopy development of the cerebellar glomeruli has been studied in the hen ontogenesis. Two successive stages have been revealed: protoglomerular (the 16th-18th days of incubation) and glomerular (the 19th day of incubation--the end of the 3d week after hatching). Specific peculiarities of their structural organization are presented. A suggestion is made on an inductive effect of the afferent mossy fibers on processes of morphological formation of the cerebellar glomeruli.

[Development of dendritic spines in the piriform neurons of the cerebellar cortex in human prenatal ontogeny]. / Razvitie dendritnykh shipikov grushevidnykh neironov kory mozzhechka v prenatal'nom periode ontogeneza cheloveka.

The submicroscopic investigation on developmental peculiarities of the dendritic spines in the piriform neurons of the cerebellar cortex has been performed during the human prenatal ontogenesis. The process of morphogenesis of the spines of the tertiary dendrites in the piriform neurons is demonstrated to start rather early--on the 24th week of embryogenesis and goes through three successive stages: 1) formation of a long cytoplasmic processes deprived of any membranous specialization; 2) formation of the terminal spinal head, making synapses with parallel fibers of the cerebellar cortex; 3) definitive stage. A suggestion is made that differentiation processes of the spines depend on inductive influence of the parallel fibers of the cerebellar cortex.

[Changes in the microviscosity of the plasma membrane and sensitivity to PGE1 of platelets stored at 22 and 4 degrees C]. / Izmenenie mikroviazkosti plazmaticheskoi membrany i chuvstvitel'nosti k PGE1 trombotsitov, khraniashchikhsia pri 22 i 4 gradusakh C.

Effect of platelet storage within 1-3 days on the cell membranes microviscosity, studied by means of a spin probe, and their sensitivity to PGEI, inhibitor of ADP aggregation, were studied. The highest values of fluidity and PGEI sensitivity exhibited plasmatic membranes of platelets stored at 22 degrees; lower values were found in the membranes stored at 4 degrees as compared with native fresh platelets. The data obtained suggest the dissimilar character of alterations in structure and functions of platelet plasmatic membrane during storage at 22 degrees and 4 degrees.

Combined action of nicotinamide and adenine in preservation of packed red cells.

An alkaline resuspension solution "Erythronaph" with adenine and nicotinamide has been developed. It allows to preserve red blood cells for 35 days. Removing leukocytes and platelets up to 90% by brief warning of 24-hour blood prior to centrifugation combined with return of 10% of plasma provide further prolongation of storage of red blood cells in "Erythronaph".

[Multiple molecular forms of esterases from grass aphids inhibitory identification and stereospecificity]. / Mnozhestvennye molekuliarnye formy ésteraz zlakovoi tli: ingibitornaia identifikatsiia i stereospetsifichnost'.

Nine esterase fractions hydrolyzing 1-naphthylacetate were revealed in Triton X-100-solubilized extracts from aphides homogenates by polyacrylamide gel electrophoresis. The less mobile fractions 1-4 were identified as cholinesterases, using specific inhibitors--eserine and the cationic phosphoorganic inhibitor Gd-42; fractions 5-7 were related to carboxylesterases, using specific inhibition by triorthocresylphosphate and O,O-dimethyl (2,2-dichlorvinyl)phosphate. The most mobile fractions 8-9 which were resistant to the inhibitors, were classified as arylesterases. The aphis cholinesterase fractions revealed the highest mobility; the activity of carboxylesterase fractions was lower. Thiophosphonate--C8H17O(CH3)P(O)-SCH2SCH2COOCH3 was found to be a highly efficient selective inhibitor of aphis carboxylesterase, i. e. the kII values for carboxylesterase and cholinesterase were equal to 10(8) and 10(5) M-1 min-1, respectively. The thiophosphoorganic derivatives containing a beta-alanine residue in the cleaved part are more specific to acetylcholinesterase and carboxylesterase than those containing a valine residue. Studies with enanthiomers--C2H5O(CH3)P(O)SCH2CONHCH2CH2COOC2H5 and (C2H5O)2P(O)SCH2CONHCH(iC3H7)COOC2H5 have demonstrated that the asymmetry due to the central phosphorus atom is more essential for the acetylcholinesterase and carboxylesterase activities than that connected with the carbon atom in the cleaved part of the inhibitor molecule. During the interaction of the enanthiomers with the asymmetric phosphorus the stereospecificity of acetylcholinesterase is much higher than that of carboxylesterase. In terms of stereospecificity of the esterase site aphis acetylcholinesterase is is similar to its mammalian counterpart, while carboxylesterase from the same source is rather close to mammalian butyrylcholinesterase.

[Inhibition of cholinesterases by aziridinium derivatives of polymethylene bischloroethylamines]. / Ingibirovanie kholinésteraz aziridinievymi proizvodnymi polimetilenbiskhlorétilaminov.

Cyclization of polymethylene bischloroethylamines, differing in the methylene chain-length (n = 6 or 10) and the N-substituents (R = CH3 or CH2C6H5), was carried out and the respective aziridinium derivatives were obtained. These derivatives of hexamethonium and decamethonium manifested reversible inhibition (Ki approximately 100-1 microM) and irreversible alkylating activity (kII approximately 10(2) M-1 . min-1) towards acetylcholinesterase from human erythrocytes and horse serum butyrylcholinesterase. Upon varying n and R, the alkylation biomolecular rate constants changed symbately with changes in the reversible inhibition constants. The most potent alkylating agent with respect to acetylcholinesterase (kII 7,8 x 10(2) M-1 . min-1) and butyrylcholinesterase (kII 4,2 . 10(2) M-1 . min-1) was found to be the aziridinium analog of hexamethonium with R = CH2C6H5. Based on the kinetic data, the problem of alkylation of anionic sites in the catalytic and allosteric centers of the two cholinesterases is discussed.