Problems and prospects for finding new pharmacological agents among adenosine receptor agonists, antagonists, or their allosteric modulators for the treatment of cardiovascular diseases.

A1-adenosine receptors (A1AR) are widely distributed in the human body and mediate many different effects. They are abundantly present in the cardiovascular system, where they control angiogenesis, vascular tone, heart rate, and conduction. This makes the cardiovascular system A1AR an attractive target for the treatment of cardiovascular diseases (CVD). The review summarizes the literature data on the structure and functioning of A1AR, and analyzes their involvement in the formation of myocardial hypertrophy, ischemia-reperfusion damage, various types of heart rhythm disorders, chronic heart failure, and arterial hypertension. Special attention is paid to the role of some allosteric regulators of A1AR as potential agents for the CVD treatment.

[Surgical treatment of sternal osteomyelitis and sternomediastinitis following cardiac surgery]. / Khirurgicheskoe lechenie osteomielita grudiny i sternomediastinita vsledstvie kardiokhirurgicheskikh operatsii.

OBJECTIVE: To analyze the incidence of cardiac surgeries and postoperative sternal osteomyelitis/sternomediastinitis, as well as treatment outcomes in these patients. MATERIAL AND METHODS: We summarized 171 patients with postoperative sternal osteomyelitis and sternomediastinitis. RESULTS: Organization of the Khabarovsk center for cardiovascular surgery in the Far Eastern Federal District was followed by 7.9- and 24.9-fold increase of the number of cardiac surgeries and CABG in 2005-2019, respectively. As a result, the number of patients with sternal osteomyelitis and sternomediastinitis after cardiac surgery increased from 0.50±0.10 to 1.59±0.17 cases per 100.000 (t=3.01; p<0.01). CPB and aortic clamping time (t=3.97; p<0.01), as well as surgery time (t=2.4; p<0.05) were significant risk factors of early postoperative complications. Two-stage surgical treatment of postoperative sternal osteomyelitis and sternomediastinitis (removal of ligatures and foreign bodies, sternal curettage with removal of sequesters at the first stage; resection of sternum with chest wall repair at the second stage) reduced hospital-stay from 31.9±13.4 to 29.2±10.8 days.

[Hygienic assessment of the impact of diesel fuel on the ordinary black soil microbiocenosis].

The main sources of soil contamination by oil products in the Dnepropetrovsk region are oil depots, gas stations and all types of transport that use and transport oil. The diesel fuel was found to be the one of the priority multicomponent components of the petroleum products, so it there was occurred the necessity for the hygienic regulation of the oil component in order to monitor a multicomponent composition ofpetroleum products in the study of complex influence of environmental factors on health population. In the study of the effect of various concentrations of diesel fuel on the number of total bacterial count (TBC) as the threshold for general sanitary indicator of hazard, there was recommended the concentration of4000 mg/kg, which oppressed the vital activity of soil microorganisms by 50-27.3% for the first 2 weeks of the laboratory experiment.

[Biosynthesis of L-lysine-alpha-oxidase, an antitumor enzyme, by Trichoderma spp].

Strains of Trichoderma spp., producing L-lysine-alpha-oxidase, prospective in chemotherapy of malignant tumors, were studied. The best results of the enzyme biosynthesis were observed on the wheat bran medium. When grown on the media with various pH levels, the strains showed different spectra of the L-aminooxidase activity. The highest activity of the strains was recorded with respect to destruction of L-lysine. The lysine-producing organism Brevibacterium sp. induced L-lysine-alpha-oxidase activity in Trichoderma spp.

Energy metabolism in rat brain structures after injections of kainic acid into the frontal cortex.

We studied behavioral reactions of rats after injection of subconvulsive dose of kainic acid into the frontal cortex and mitochondrial respiration in the hippocampus and frontal and temporal cortex 17-20 days after administration of kainic acid. Retention of acquired habit and the dynamics of its extinction in experimental rats were close to those in the control group. Changes in mitochondrial function were observed only in the region of kainic acid injection: activation of phosphorylating respiration during oxidation of succinate. Presumably, the detected activation of energy metabolism in the frontal cortex indicates functional restructuring in mitochondria, aimed at compensation of disorders caused by the neurotoxin.

[APUD- and RAA- regulatory systems in acute radiation injury]. / APUD- i RAA-sistemy reguliatsii pri ostrom radiatsionnom porazhenii.

An experimental morpho-functional assessment of rat APUD and RAA systems status in acute radiation injury (cerebral form) was performed. The named regulatory systems were found to display an actual momentary post-exposure reaction, followed by subsequent functional changes of a distinct phase character. The latter were shown to determine in many respects the clinical picture and in some cases the outcome of the disease.

[Tuberculosis of the respiratory tract and chronic alcoholism]. / Tuberkulez organov dykhaniia i khronicheskii alkogolizm.

Tuberculosis of respiratory organs was studied in chronic alcoholics under the conditions of an industrial city the Republic of Byelarus after the Chernobyl atomic power plant accident. Respiratory tuberculosis was found to occur in chronic alcoholics more frequently than in those without chronic alcoholism, to run relatively badly, destructive form and bacterial isolation being commonly, therapeutical efficiency in them was reduced, and long-term prognosis was under question. Controlled combined anti-tuberculous and antialcoholic treatment should be performed in chronic alcoholics with tuberculosis.

MIC-based interspecies prediction of the antimicrobial effects of ciprofloxacin on bacteria of different susceptibilities in an in vitro dynamic model.

Multiple predictors of fluoroquinolone antimicrobial effects (AMEs) are not usually examined simultaneously in most studies. To compare the predictive potentials of the area under the concentration-time curve (AUC)-to-MIC ratio (AUC/MIC), the AUC above MIC (AUCeff), and the time above MIC (Teff), the kinetics of killing and regrowth of four bacterial strains exposed to monoexponentially decreasing concentrations of ciprofloxacin were studied in an in vitro dynamic model. The MICs of ciprofloxacin for clinical isolates of Staphylococcus aureus, Escherichia coli 11775 (I) and 204 (II), and Pseudomonas aeruginosa were 0.6, 0.013, 0.08, and 0.15 microg/ml, respectively. The simulated values of AUC were designed to provide similar 1,000-fold (S. aureus, E. coli I, and P. aeruginosa) or 2, 000-fold (E. coli II) ranges of the AUC/MIC. In each case except for the highest AUC/MIC ratio, the observation periods included complete regrowth in the time-kill curve studies. The AME was expressed by its intensity, IE (the area between the control growth and time-kill and regrowth curves up to the point where the viable counts of regrowing bacteria are close to the maximum values observed without drug). For most AUC ranges the IE-AUC curves were fitted by an Emax (maximal effect) model, whereas the effects observed at very high AUCs were greater than those predicted by the model. The AUCs that produced 50% of maximal AME were proportional to the MICs for the strains studied, but maximal AMEs (IEmax) and the extent of sigmoidicity (s) were not related to the MIC. Both Teff and log AUC/MIC correlated well with IE (r2 = 0.98 in both cases) in a species-independent fashion. Unlike Teff or log AUC/MIC, a specific relationship between IE and log AUCeff was inherent in each strain. Although each IE and log AUCeff plot was fitted by linear regression (r2 = 0.97 to 0.99), these plots were not superimposed and therefore are bacterial species dependent. Thus, AUC/MIC and Teff were better predictors of ciprofloxacin's AME than AUCeff. This study suggests that optimal predictors of the AME produced by a given quinolone (intraquinolone predictors) may be established by examining its AMEs against bacteria of different susceptibilities. Teff was shown previously also to be the best interquinolone predictor, but unlike AUC/MIC, it cannot be used to compare different quinolones. AUC/MIC might be the best predictor of the AME in comparisons of different quinolones.

A new approach to in vitro comparisons of antibiotics in dynamic models: equivalent area under the curve/MIC breakpoints and equiefficient doses of trovafloxacin and ciprofloxacin against bacteria of similar susceptibilities.

Time-kill studies, even those performed with in vitro dynamic models, often do not provide definitive comparisons of different antimicrobial agents. Also, they do not allow determinations of equiefficient doses or predictions of area under the concentration-time curve (AUC)/MIC breakpoints that might be related to antimicrobial effects (AMEs). In the present study, a wide range of single doses of trovafloxacin (TR) and twice-daily doses of ciprofloxacin (CI) were mimicked in an in vitro dynamic model. The AMEs of TR and CI against gram-negative bacteria with similar susceptibilities to both drugs were related to AUC/MICs that varied over similar eight-fold ranges [from 54 to 432 and from 59 to 473 (microg . h/ml)/(microg/ml), respectively]. The observation periods were designed to include complete bacterial regrowth, and the AME was expressed by its intensity (the area between the control growth in the absence of antibiotics and the antibiotic-induced time-kill and regrowth curves up to the point where viable counts of regrowing bacteria equal those achieved in the absence of drug [IE]). In each experiment monoexponential pharmacokinetic profiles of TR and CI were simulated with half-lives of 9.2 and 4.0 h, respectively. Linear relationships between IE and log AUC/MIC were established for TR and CI against three bacteria: Escherichia coli (MIC of TR [MICTR] = 0.25 microg/ml; MIC of CI [MICCI] = 0.12 microg/ml), Pseudomonas aeruginosa (MICTR = 0.3 microg/ml; MICCI = 0.15 microg/ml), and Klebsiella pneumoniae (MICTR = 0.25 microg/ml; MICCI = 0.12 microg/ml). The slopes and intercepts of these relationships differed for TR and CI, and the IE-log AUC/MIC plots were not superimposed, although they were similar for all bacteria with a given antibiotic. By using the relationships between IE and log AUC/MIC, TR was more efficient than CI. The predicted value of the AUC/MIC breakpoint for TR [mean for all three bacteria, 63 (microg . h/ml)/(microg/ml)] was approximately twofold lower than that for CI. Based on the IE-log AUC/MIC relationships, the respective dose (D)-response relationships were reconstructed. Like the IE-log AUC/MIC relationships, the IE-log D plots showed TR to be more efficient than CI. Single doses of TR that are as efficient as two 500-mg doses of CI (500 mg given every 12 h) were similar for the three strains (199, 226, and 203 mg). This study suggests that in vitro evaluation of the relationships between IE and AUC/MIC or D might be a reliable basis for comparing different fluoroquinolones and that the results of such comparative studies may be highly dependent on their experimental design and datum quantitation.

Inter- and intraquinolone predictors of antimicrobial effect in an in vitro dynamic model: new insight into a widely used concept.

Earlier efforts to search for pharmacokinetic and bacteriological predictors of fluoroquinolone antimicrobial effects (AMEs) have resulted in conflicting findings. To elucidate whether these conflicts are real or apparent, several predictors of the AMEs of two pharmacokinetically different antibiotics, trovafloxacin (TRO) and ciprofloxacin (CIP), as well as different dosing regimens of CIP were examined. The AMEs of TRO given once daily (q.d.) and CIP given q.d. and twice daily (b.i.d.) against Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae were studied in an in vitro dynamic model. Different monoexponential pharmacokinetic profiles were simulated with a TRO half-life of 9.2 h and a CIP half-life of 4.0 h to provide similar eightfold ranges of the area under the concentration-time curve (AUC)-to-MIC ratios, from 54 to 432 and from 59 to 473 (microg x h/ml)/(microg/ml), respectively. In each case the observation periods were designed to incorporate full-term regrowth phases in the time-kill curves, and the AME was expressed by its intensity (IE; the area between the control growth and time-kill and regrowth curves up to the point at which the viable counts of regrowing bacteria are close to the maximum values observed without drug). Species-independent linear relationships were established between IE and log AUC/MIC, log AUC above MIC (log AUCeff), and time above the MIC (Teff). Specific and nonsuperimposed IE versus log AUC/MIC or log AUCeff relationships were inherent in each of the treatments: TRO given q.d. (r2 = 0.97 and 0.96), CIP given q.d. (r2 = 0.98 and 0.96), and CIP given b.i.d. (r2 = 0.95 and 0.93). This suggests that in order to combine data sets obtained with individual quinolones to examine potential predictors, one must be sure that these sets may be combined. Unlike AUC/MIC and AUCeff, the IE-Teff relationships plotted for the different quinolones and dosing regimens were nonspecific and virtually superimposed (r2 = 0.95). Hence, AUC/MIC, AUCeff and Teff were equally good predictors of the AME of each of the quinolones and each dosing regimen taken separately, whereas Teff was also a good predictor of the AMEs of the quinolones and their regimens taken together. However, neither the quinolones nor the dosing regimens could be distinguished solely on the basis of Teff whereas they could be distinguished on the basis of AUC/MIC or AUCeff. Thus, two types of predictors of the quinolone AME may be identified: intraquinolone and/or intraregimen predictors (AUC/MIC, AUCeff and Teff) and an interquinolone and interregimen predictor (Teff). Teff may be able to accurately predict the AME of one quinolone on the basis of the data obtained for another quinolone.

[Digestion of Luliberine analogues containing D-alanine residue by human gastric juice]. / Rasshcheplenie zheludochnym sokom cheloveka analogov liuliberina, soderzhashchich ostatok D-alanina.

The digestion of surphagone and other luliberine analogues containing residues of D-amino acids by human gastric juice was studied. By means of chromatography and mass spectrometry, these peptides were shown to undergo hydrolysis of the bond formed by D-Ala at the P-1 position, and this hydrolysis was shown to be catalyzed by gastricsin rather than pepsin A. Gastricsin was assumed to be a highly specific protease. The results are in a good agreement with the concept of conformational specificity of proteases towards the natural oligopeptides.

Parameters of bacterial killing and regrowth kinetics and antimicrobial effect examined in terms of area under the concentration-time curve relationships: action of ciprofloxacin against Escherichia coli in an in vitro dynamic model.

Although many parameters have been described to quantitate the killing and regrowth of bacteria, substantial shortcomings are inherent in most of them, such as low sensitivity to pharmacokinetic determinants of the antimicrobial effect, an inability to predict a total effect, insufficient robustness, and uncertain interrelations between the parameters that prevent an ultimate determination of the effect. To examine different parameters, the kinetics of killing and regrowth of Escherichia coli (MIC, 0.013 microg/ml) were studied in vitro by simulating a series of ciprofloxacin monoexponential pharmacokinetic profiles. Initial ciprofloxacin concentrations varied from 0.02 to 19.2 microg/ml, whereas the half-life of 4 h was the same in all experiments. The following parameters were calculated and estimated: the time to reduce the initial inoculum (N0) 10-, 100-, and 1,000-fold (T90%, T99%, and T99.9%, respectively), the rate constant of bacterial elimination (k(elb)), the nadir level (Nmin) in the viable count (N)-versus-time (t) curve, the time to reach Nmin (t(min)), the numbers of bacteria that survived (Ntau) by the end of the observation period (tau), the area under the bacterial killing and regrowth curve (log N(A)-t curve) from the zero point (time zero) to tau (AUBC), the area above this curve (AAC), the area between the control growth curve (log N(C)-t curve) and the bacterial killing and regrowth curve (log N(A)-t curve) from the zero point to tau (ABBC) or to the time point when log N(A) reaches the maximal values observed in the log N(C)-t curve (I(E); intensity of the effect), and the time shift between the control growth and regrowth curves (T(E); duration of the effect). Being highly sensitive to the AUC, I(E), and T(E) showed the most regular AUC relationships: the effect expressed by I(E) or T(E) increased systematically when the AUC or initial concentration of ciprofloxacin rose. Other parameters, especially T90%, T99%, T99.9%, t(min), and log N0 - log Nmin = delta log Nmin, related to the AUC less regularly and were poorly sensitive to the AUC. T(E) proved to be the best predictor and t(min) proved to be the worst predictor of the total antimicrobial effect reflected by I(E). Distinct feedback relationships between the effect determination and the experimental design were demonstrated. It was shown that unjustified shortening of the observation period, i.e., cutting off the log N(A)-t curves, may lead to the degeneration of the AUC-response relationships, as expressed by log N0 - log Ntau = delta log Ntau, AUBC, AAC, or ABBC, to a point where it gives rise to the false idea of an AUC- or concentration-independent effect. Thus, use of I(E) and T(E) provides the most unbiased, robust, and comprehensive means of determining the antimicrobial effect.

Purification of soluble and membrane forms of somatic angiotensin-converting enzyme by cascade affinity chromatography.

Soluble and membrane forms of angiotensin-converting enzyme were purified by cascade affinity chromatography. The enzyme forms were completely separated from each other using their different affinity to the hydrophobic matrix phenyl-silochrome. The enzymes was further purified on affinity sorbent prepared by immobilization of the enzyme inhibitor N-[1(S)-carboxy-5-aminopentyl]glycylphenylalanine on agarose. The procedure yielded electrophoretically homogeneous soluble and membrane forms of angiotensin-converting enzyme containing only active molecules as demonstrated by titration with the reversible inhibitor lisinopril. According to phase separation in the presence of Triton X-114, the membrane enzyme is more hydrophobic than the soluble form. The catalytic characteristics of the enzyme forms differed from each other in the system Aerosol OT-water-octane (reversed micelles) which is model for the membrane environment of the enzymes in vivo.

[Proteolysis of human proinsulin catalysed by native, modified, and immobilized trypsin]. / Proteoliz proinsulina cheloveka, kataliziruemyi nativnym, modifitsirovannym i immobilizirovannym tripsinom.

Proteolysis of recombinant human proinsulin by the native trypsin, by trypsin modified with a copolymer of vinylpyrrolidone and acrolein, and by the same modified trypsin immobilized on Silochrom 1.5 was studied by RP HPLC and mass spectrometry. Rate constants of the main stages of proinsulin hydrolysis by the native trypsin were estimated. The values of rate constants of the digestions of the most easily hydrolyzable bonds (those formed by the pairs of the basic amino acid residues) in proinsulin were found to be of the same order as those formed by the separate lysine residues (Lys7) and those formed by the four basic amino acid residues of the C-terminal cluster of melittin. It was established that covalent trypsin binding to the copolymer did not change the ratio of the rate constants of the individual stages of proinsulin hydrolysis, whereas after the immobilization of modified trypsin on the Silochrome, the formation of diarginyl insulin-ArgArg, intermediate forms of hydrolyzed insulin, and desThr-insulin proceeds with comparable rates.

[A method of calculation of accessibility to solvent of aromatic amino acid residues of proteins in water-organic mixtures]. / Metod rascheta dostupnosti rastvoriteliu aromaticheskikh aminokislotnykh ostatkov belkov v vodno-organicheskikh smesiakh.

Suggested method for calculation of solvent accessibility of tryptophan and tyrosine residues in water-organic mixtures is based on evaluation of second order derivatives of UV spectra. Second order derivative of the spectrum enable differentiation between direct effects of the organic solvent on spectral characteristics of exposed aromatic amino acid residues and the effect of the organic solvent on protein conformation. The method is suitable for calculation of exposition of tryptophan in water-organic mixtures if the content of tyrosine amino acid residues in protein does not exceed the content of tryptophan. Similar method of calculation of exposition of tyrosine residues can be used in proteins when the content of tyrosine is at least 5-fold higher than the content of tryptophan. For example, solvent accessibility of tryptophan residues of chymotrypsin is calculated in the presence of various organic solvents including ethanol, dioxane, and dimethyl formamide.

Electrospray mass spectrometric study of melittin trypsinolysis by a kinetic approach.

The kinetics of tryptic digestion of melittin was studied by combined electrospray ionization time-of-flight mass spectrometry and high-performance liquid chromatography. The ratios of the kinetic constants for cleavage of the peptide bonds that are susceptible to trypsin action were determined. It is shown that trypsin does not manifest affinity for the hydrolysis of the peptide bonds inside the Arg,Lys cluster series as efficiently as it cleaves the peptide at the separately localized Lys residue. This feature demonstrates clearly the advantage of the kinetic approach to tryptic mapping of proteins. The kinetic approach allows the determination of not only discrete structural segments in protein structure but also their relative locations and their amino acid sequences. Using the melittin digests and some artificially prepared amino acids and dipeptides mixtures as models, it is shown that the presence and nature of basic amino acids predetermines the charge states of the molecules analyzed by electrospray but not the yields of their ions. The aliphatic parts of the molecules seem to be more important in determining the actual ion yields.

[Structure and biological properties of a conjugate of Bowman-Birk type soy proteinase inhibitor with a block copolymer of ethylene oxide and propylene oxide]. / Stroenie i biologicheskie svoistva kon''iugata soevogo ingibitora proteinaz tipa Baumana-Birk s blok-sopolimerov okisi étilena i okisi propilena.

The structure of the conjugate of Bowman-Birk soybean proteinase inhibitor (BBI) with the block copolymer of ethylene oxide and propylene oxide (proxanol) containing five moles of proxanol per mole of protein, has been studied. Data from reverse phase hydrophobic HPLC suggest that the conjugate is less hydrophobic compared to native BBI. A shift of the second derivative UV absorption spectrum for the conjugate towards the shortwave region indicates a greater accessibility of the Tyr-59 residue localized in the interdomain region of the BBI molecule for the solvent. It has been assumed that the conjugate-induced increase in Ki for chymotrypsin may be due to both disturbances in the intact structure of the interdomain region of BBI and screening of the anti-chymotrypsin reactive center as a result of hydrophobic interactions of propylene oxide blocks of proxanol with exposed hydrophobic groups around the reactive center. Supporting evidence in favour of BBI molecule hydrophilization as a result of modification by proxanol can be derived from decreased conjugate penetration into intestinal epithelial cells as well as from the slow elimination of the conjugate from mouse blood stream.

[Determination of solvent accessibility of residues of aromatic amino acids in proteins using the second derivative of the UV-absorption spectrum]. / Opredelenie dostupnosti rastvoriteliu ostatkov aromaticheskikh aminokislot v belkakh po vtorym proizvodnym UF-spektrov pogloshcheniia.

A new method for determining the solvent accessibility of tyrosine and tryptophan residues in proteins from the wavelengths of absorption peak maxima in secondary derivatives of UV absorption spectra has been developed. Analytical expressions for calculating the number of groups in latent and exposed states of amino acid residues in protein globules were obtained on the basis of the previously elaborated mathematical model of spectral changes observed during the transition between those respective states. The new procedure was used to analyze sixteen proteins and showed a good correlation between the experimental results and literary data.

[A quantitative method for evaluating the structure and conformational stability of proteins by second derivative UV-spectroscopy]. / Kolichestvennyi metod otsenki struktury i konformatsionnoi ustoichivosti belkov po vtorym proizvodnym UF-specktrov pogloshcheniia.

A quantitative method is suggested for estimating the structure and conformational stability of proteins based on the individual absorbance of Tyr residues in the second derivative UV spectra. Subtilisins Carlsberg, BPN' and 72 were chosen as the model proteins. The values of the increase of the Tyr absorption at 282.3 nm upon the total denaturation of the proteins made it possible to calculate the number of the exposed and "buried" tyrosine residues in the native proteins. A mathematical model of spectrum changes during the transition of Tyr residues from the "buried" to exposed form is suggested. The method is useful for the determination of the denaturation constants of proteins bearing "buried" tyrosine residues.