Inhibition of cytosolic Ca++ mobilization in human platelets by the antianginal drug trapidil and its derivative AR 12463.

The antianginal drug trapidil (5-methyl-7-diethylamino-s-triazolo-(1.5-a)pyrimidine) and its derivative AR 12463 (5-piperidino-7-(N-(n-amyl)-N-(beta-hydroxyethyl)-amino)-s-triazolo(1.5- a) pyrimidine) inhibit the thromboxane A2 agonist (U-46619)-induced mobilization of intracellular platelet-free Ca++ as measured with the fluorescent Ca++ indicator Indo-1.

Optimization of the grating efficiency in grazing incidence.

A detailed numerical study of the sinusoidal and triangular groove shape grating efficiency behavior has been carried out in grazing incidence using rigorous electromagnetic theory. The optimized parameters for maximum efficiency have been found for both types of grating. The influence of the metal reflectance and the oxide layer are discussed, and some results of higher order efficiency are also presented.

[Accumulation of acridine amino derivatives by electron-dense granules in thrombocytes].

The uptake and release of dense bodies' content were studied using fluorescent amines. Real-time measurements of fluorescence spectra by a device developed on the basis of a multichannel optical analyzer and computer technique of spectrum deconvolution made it possible to investigate the kinetics of monoamine uptake and release in intact cells.

Accumulation and release of acridine derivatives by intact platelets.

A new approach to the investigation of accumulation of acridine derivatives and release by platelets is proposed. At high concentrations of acridine orange (AO) inside dense bodies, a two component fluorescence spectrum with maxima at 530 and 640 nm has been recorded. Computer deconvolution of spectra provided additional information on the mechanism of dye accumulation and release.

Asymmetrical trapezoidal grating efficiency.

The diffraction efficiency behavior of reflection gratings with an asymmetrical trapezoidal groove profile has been studied. Theoretical calculations predict that at certain grating parameters superior efficiency compared to the conventional ruled gratings can be achieved.

[Quantitative evaluation of the uptake capacity of intact thrombocytes using fluorescent dyes].

A new approach to quantitative determination of fluorescent dye uptake by intact cells is suggested. Fluorescent amine acridine orange selectively accumulating in 5HT granules of platelets has been used. Fluorescence signal analysis allows the estimation of a relative granule volume and the ratios of acridine orange transfer over cytoplasmic and granule membranes.

[Androgen-protein interactions in the cytosol of the liver and prostate in aging].

The androgen-protein interactions in liver and ventral prostate cytosol of immature (1.5 months), young (6 months), mature (12 months) and old (24 months) male rats were studied. The minimum content and maximum values of association constant of testosterone-binding proteins in liver cytosol were observed in immature rats.

[Platelet aggregation in severe and malignant forms of hypertension: effect of treatment with prostaglandin E2].

Platelet aggregation was studied in patients with high and stable arterial hypertension that was mostly associated with the malignant syndrome, and the effect of PGE2 introduced into the blood flow as repeated intravenous infusions on platelet activity was assessed. The addition of low-dose inductor produced the greatest changes in platelet aggregation following platelet exposure to different ADP doses in the patients, as compared to normal subjects. Stimulation with 0.

[Structure-functional organization of the secretin molecule. III. Reverse conformation problem].

A solution of the "reverse conformational problem" for secretin enables one to predict a series of modified synthetic analogs, the spatial structures of which may assume one of the low-energy states of the native hormone.

[Structure-functional organization of the secretin molecule. II. Direct conformation problem].

Spatial structure of peptide hormone secretin was investigated by the theoretical conformational method. A solution of the "direct conformational problem" for this hormone indicated that the possible structure of the secretin molecule under polar conditions may be described only by two families of low-energy conformations, possessing relatively conformational valid (Thr7-Leu22) and variable (His1-Phe6 and Leu23-Val27NH2) fragments. One of these families is comprised by five twists of the alpha-helix, while the second isoenergetic family possesses two short segments of the alpha-helix, divided by an irregular structure of the tetrapeptide.

[Structure-functional organization of the secretin molecule. I. Theoretical conformation analysis of the His1-Arg18 fragment].

Theoretical conformational analysis of the octadecapeptide His1-Arg18, corresponding to the entire amino acid sequence of porcine secretin was carried out for a solution of the "direct conformational problem" for this peptide molecule.

[Conformation states of thymopentin and its synthetic analogs].

Spatial structures of the biologically active fragment Arg-Lys-Asp-Val-Tyr of tymopoetin (tymopentin) and its synthetic analogs: [Lys1-Arg2]-, [Glu3]- and [Gly3] have been investigated by theoretical conformational analysis. These results indicate that the conformational properties of fragments are represented in aqueous solution by five different backbone forms.

Effect of alternating pressure on thrombin-stimulated platelets.

The effect of alternating pressure on several basic physiological processes of thrombin-stimulated platelets, e.g. shape changes, release of adenine nucleotides and activation of arachidonic platelet system was studied.

[Mechanical activity of the vascular wall: the choice of optimum conditions for the study of isolated ring segments].

A new method for the study of vascular helical segments is described. The method, permitting simulation of mechanical conditions in vivo, can cause substantial changes in the experiments studying regulatory reactions in isolated fragments of the vascular bed.

[Conformational aspects of beta-trypsin interaction with substrates and pancreatic trypsin inhibitor. III. Catalytic act of trypsin and its inhibition].

Basing on the results of the theoretical conformational analysis of the nonbonded and valence complexes of trypsin with substrate molecules, the catalytical act of the enzyme is described in details as a spontaneous process. Conformational aspects of interactions of trypsin with pancreatic trypsin inhibitor are analysed. The complete inhibition process and the geometry of the enzyme-inhibitor complex are described in details.

[Conformational aspects of beta-trypsin interactions with substrates and pancreatic trypsin inhibitor. II. Structure of tetrahedral adducts and acylenzyme].

Theoretical conformational analysis of the tetrahedral complexes of trypsin with the N-acetyl-L-lysine methyl amide, which are formed at the acylation and the deacylation stages of the catalytical act has been carried out. The lowest energy conformations are shown to be productive ones. All favorable structures of N-acetyl-L-lysyl-trypsin and N-acetyl-L-arginyl-trypsin acylenzymes have been analysed.

[Effect of alternating pressure on thrombin-stimulated thrombocytes].

The effect of alternating pressure on circulating platelet function was studied with particular reference to changes in platelet shape, aggregation and release reaction, MDA synthesis and intracellular calcium redistribution. Pressure effects were dependent on the magnitude of pressure impulses, platelet suspension storage time and the interval between the exposure to pressure and the challenge of platelets.

Theoretical conformational analysis of brain peptides. beta-Melanocyte-stimulating hormone.

Using a semi-empirical method, an a priori conformational analysis of the octadecapeptide beta-melanocyte-stimulating hormone (beta-MSH) was carried out. The spatial structure of beta-MSH can be described by eight low-energy conformations, yielded by combinations of the most stable states of the respective free fragments. Calculations produced the values of all dihedral angles of the backbones and side chains of these forms as well as intra- and inter-residue interaction energies.

[Conformational aspects of beta-trypsin interaction with substrates and pancreatic trypsin inhibitor. I. Conformational properties of residues in the enzyme-active center and the structure of a non-valent enzyme-substrate complex].

The theoretical conformational analysis of potential surfaces of Ser-195, His-57, Asp-102 and Gln-192 side chains in the active center of native beta-trypsin has been carried out. The above residues are shown to exist in low-energy conformational states in the free enzyme and in its nonbonded substrate complexes. Interrelations between the flexibility of the residues and their catalytical functions were revealed.

[An approach to the problem of the structuro-functional organization of natural peptides].

Theory and computational scheme of three-dimensional structure and dynamic conformational properties of naturally occurring peptides are proposed basing on a known amino acid sequence. The diverse biological activity of a low-molecular peptide is shown to arise from a restricted number of preferable spatial structures which may occur under physiological conditions. Each particular function of an oligopeptide is connected to a definite spatial structure, belonging to the set of low-energy conformations from one biological activity of a peptide shift of the conformational equilibrium caused by a change of environmental conditions.

[Intralymphatic administration of antibiotics in the complex treatment of suppurative complications in patients with neurosurgical pathology].

The efficacy of endolymphatic route of gentamicin and ceporin administration was studied in 89 patients with neurosurgical pathological processes complicated by acute pneumonia (80 patients) and meningoencephalitis (9 patients) usually after ineffective antibiotic therapy according to the routine methods. The antibiotics were used in accordance with the antibiograms of the causative agents isolated from the bronchial tree or CSF. The endolymphatic use of gentamicin or ceporin once a day in doses of 80 mg or 1 g respectively provided rapid sanation and arresting of the inflammatory foci, lowering of the intoxication level, more rapid promotion of the positive time course of the clinico-roentgenological and laboratory indices and decreasing of the recovery periods by 1.