[The anti-ischemic and antioxidant activity of the pharmacological agonist of galanin receptor GalR2 and carnosine in in vitro and in vivo model systems]

Antioxidant and anti-ischemic properties of the pharmacological agonist of galanin receptor GalR2 WTLNSAGYLLGPβAH (Gal) and its C-terminal fragment, dipeptide carnosine (βAH), were studied in the model of regional ischemia and reperfusion of the rat heart in vivo in the dose range of 0.5-5.0 mg/kg and Cu²⁺-induced free radical oxidation of low density lipoproteins (LDL) of human plasma in vitro for peptide concentrations of 0.01 mM and 0.1 mM. Gal was obtained by automatic solid phase synthesis using the Fmoc methodology; its structure was characterized by 1H-NMR spectroscopy and MALDI-TOF mass spectrometry. Intravenous administration of the optimal dose of Gal (1 mg/kg) to rats after ischemia was more effective than carnosine in reducing of the myocardial infarct size and the activity of creatine kinase-MB and lactate dehydrogenase in blood plasma at the end of reperfusion. It also improved the metabolic state of the reperfused myocardium and reduced the formation of peroxidation products during reperfusion. Gal reduced more effectively the formation of adducts of hydroxyl radicals in the interstitium of the area at risk (AAR) of the rat heart than carnosine. Carnosine at a dose of 1 mg/kg more effectively increased the activity of catalase and glutathione peroxidase in the AAR by the end of reperfusion compared to Gal. In a model of Cu²⁺-initiated oxidation of human plasma LDL 0.1 mM carnosine demonstrated a significantly more pronounced reduction in the formation of lipid radicals compared to Gal. The results show that Gal can be considered as a promising agent that reduces myocardial injury during reperfusion and oxidative stress.

Chimeric Agonist of Galanin Receptor GALR2 Reduces Heart Damage in Rats with Streptozotocin-Induced Diabetes

Neuropeptide galanin and its N-terminal fragments reduce the generation of reactive oxygen species and normalize metabolic and antioxidant states of myocardium in experimental cardiomyopathy and ischemia/reperfusion injury. The aim of this study was to elucidate the effect of WTLNSAGYLLGPβAH-OH (peptide G), a pharmacological agonist of the galanin receptor GalR2, on the cardiac injury induced by administration of streptozotocin (STZ) in rats. Peptide G was prepared by solid phase peptide synthesis using the Fmoc strategy and purified by preparative HPLC; its structure was confirmed by 1H-NMR spectroscopy and MALDI-TOF mass spectrometry. Experimental animals were randomly distributed into five groups: C, control; S, STZ-treated; SG10, STZ + peptide G (10 nmol/kg/day); SG50, STZ + peptide G (50 nmol/kg/day); G, peptide G (50 nmol/kg/day). Administration of peptide G prevented hyperglycemia in SG50 rats. By the end of the experiment, the ATP content, total pool of adenine nucleotides, phosphocreatine (PCr) content, and PCr/ATP ratio in the myocardium of animals of the SG50 group were significantly higher than in rats of the S group. In the SG50 and SG10 groups, the content of lactate and lactate/pyruvate ratio in the myocardium were reduced, while the glucose content was increased vs. the S group. Both doses of peptide G reduced the activation of creatine kinase-MB and lactate dehydrogenase, as well as the concentration of thiobarbituric acid reactive products in the blood plasma of STZ-treated rats to the control values. Taken together, these results suggest that peptide G has cardioprotective properties in type 1 diabetes mellitus. Possible mechanisms of peptide G action in the STZ-induced diabetes are discussed.

212Pb: Production Approaches and Targeted Therapy Applications

Over the last decade, targeted alpha therapy has demonstrated its high effectiveness in treating various oncological diseases. Lead-212, with a convenient half-life of 10.64 h, and daughter alpha-emitter short-lived ²¹²Bi (T_1/2 = 1 h), provides the possibility for the synthesis and purification of complex radiopharmaceuticals with minimum loss of radioactivity during preparation. As a benefit for clinical implementation, it can be milked from a radionuclide generator in different ways. The main approaches applied for these purposes are considered and described in this review, including chromatographic, solution, and other techniques to isolate ²¹²Pb from its parent radionuclide. Furthermore, molecules used for lead’s binding and radiochemical features of preparation and stability of compounds labeled with ²¹²Pb are discussed. The results of preclinical studies with an estimation of therapeutic and tolerant doses as well as recently initiated clinical trials of targeted radiopharmaceuticals are presented.

Peptide Inhibitors of the Interaction of the SARS-CoV-2 Receptor-Binding Domain with the ACE2 Cell Receptor

Computer simulation has been used to identify peptides that mimic the natural target of the SARS-CoV-2 coronavirus spike (S) protein, the angiotensin-converting enzyme type 2 (ACE2) cell receptor. Based on the structure of the complex of the protein S receptor-binding domain (RBD) and ACE2, the design of chimeric molecules consisting of two 22-23-mer peptides linked to each other by disulfide bonds was carried out. The chimeric molecule X1 was a disulfide dimer, in which terminal cysteine residues in the precursor molecules h1 and h2 were connected by the S-S bond. In the chimeric molecule X2, the disulfide bond was located in the middle of each precursor peptide molecule. The precursors h1 and h2 mimic amino acid sequences of α1- and α2-helices of the ACE2 extracellular peptidase domain, respectively, keeping intact most of the amino acid residues involved in the interaction with RBD. The aim of the work was to evaluate the binding efficiency of chimeric molecules and their constituent peptides with RBD (particularly in dependence of the middle and terminal methods of fixing the initial peptides h1 and h2). The proposed polypeptides and chimeric molecules were synthesized by chemical methods, purified to 95-97% purity, and characterized by HPLC and MALDI-TOF mass spectrometry. Binding of these peptides to the SARS-CoV-2 RBD was evaluated by microthermophoresis with recombinant domains corresponding in sequence to the original Chinese (GenBank ID NC_045512.2) and the British (B. 1.1.7, GISAID EPI_ISL_683466) variants. The original RBD of the Chinese variant bound to three synthesized peptides: linear h2 and both chimeric variants. Chimeric peptides were also bound to the RBD of the British variant. The antiviral activity of the proposed peptides was evaluated in Vero cell line.

[Peptide inhibitors of the interaction of the SARS-CoV-2 receptor-binding domain with the ACE2 cell receptor]

Computer simulation has been used to identify peptides that mimic the natural target of the SARS-CoV-2 coronavirus spike (S) protein, the angiotensin converting enzyme type 2 (ACE2) cell receptor. Based on the structure of the complex of the protein S receptor-binding domain (RBD) and ACE2, the design of chimeric molecules consisting of two 22-23-mer peptides linked to each other by disulfide bonds was carried out. The chimeric molecule X1 was a disulfide dimer, in which edge cysteine residues in the precursor molecules h1 and h2 were connected by the S-S bond. In the chimeric molecule X2, the disulfide bond was located in the middle of the molecule of each of the precursor peptides. The precursors h1 and h2 modelled amino acid sequences of α1- and α2-helices of the extracellular peptidase domain of ACE2, respectively, keeping intact most of the amino acid residues involved in the interaction with RBD. The aim of the work was to evaluate the binding efficiency of chimeric molecules and their RBD-peptides (particularly in dependence of the middle and edge methods of fixing the initial peptides h1 and h2). The proposed polypeptides and chimeric molecules were synthesized by chemical methods, purified (to 95-97% purity), and characterized by HPLC and MALDI-TOF mass spectrometry. The binding of the peptides to the SARS-CoV-2 RBD was evaluated by microthermophoresis with recombinant domains corresponding in sequence to the original Chinese (GenBank ID NC_045512.2) and the British (B. 1.1.7, GISAID EPI_ISL_683466) variants. Binding to the original RBD of the Chinese variant was detected in three synthesized peptides: linear h2 and both chimeric variants. Chimeric peptides were also bound to the RBD of the British variant with micromolar constants. The antiviral activity of the proposed peptides in Vero cell culture was also evaluated.

[Protective action of a modified fragment of galanine in rats with doxorubicin-induced heart failure]

The use of the anticancer drug doxorubicin (Dox) is limited due to its cardiotoxic effect. Using the method of automatic solid-phase peptide synthesis, we obtained a synthetic agonist of galanin receptors GalR1-3 [RAla14, His15]-galanine (2-15) (G), exhibiting cardioprotective properties. It was purified by high performance liquid chromatography (HPLC). The homogeneity and structure of the peptide was confirmed by HPLC, 1H-NMR spectroscopy and mass spectroscopy. The purpose of this study was to study the effect of G on the metabolism and cardiac function of rats with chronic heart failure (CHF) caused by Dox. Experiments were performed using male Wistar rats weighing 280-300 g. The control group of animals (C) was intraperitoneally treated with saline for 8 weeks; the doxorubicin group (D) of rats was intraperitoneally treated with Doх; the group of Doх + peptide G (D+G) received intraperitoneally injections of Doх and subcutaneously injections of peptide G; the peptide G group (G) was subcutaneously treated with G. At the beginning and at the end of the study, the concentration of thiobarbituric acid reactive substances (TBARS) and the activity of creatine kinase-MB (CK-MB) were determined in blood plasma; the animals were weighed, and cardiac function was assessed using echocardiography. At the end of the experiments, the hearts were used for determination of metabolites and assessment of oxidative phosphorylation in mitochondria. After 8-week treatment, animals of group D were characterized by severe heart failure, the lack of weight gain and an increase in plasma TBARS concentration and CK-MB activity. These disorders were accompanied by a decrease in the content of myocardial high-energy phosphates, a reduction inmitochondrial respiratory parameters, accumulation of lactate and glucose in the heart, and disturbances in the metabolism of alanine and glutamic and aspartic acids. Coadministration of G and Dox prevented the increase in plasma CK-MB activity and significantly reduced the plasma TBARS concentration. At the end of the experiments animals of group D+G had higher myocardial energy state and the respiratory control index of mitochondria than animals of group D, there was a decrease in anaerobic glycolysis and no changes in the amino acid content compared to the control. The peptide G significantly improved the parameters of cardiac function and caused weight gain in animals of group D+G in comparison with these parameters in group D. The obtained results demonstrate the ability of a novel agonist of galanin receptors GalR1-3 to attenuate Dox-indiced cardiotoxicity.

[Cardiometabolic efficacy and toxicological evaluation of a pharmacological galanin receptor agonist]

The goal of this study was to examine effects of a novel galanin receptor agonist GalR1-3 [bAla14, His15]-galanine 2-15 (G), obtained by automatic solid-phase synthesis, on the metabolic state of the area at risk and the size of acute myocardial infarction (MI) in rats in vivo and evaluate its toxicity in BALB /c mice. In anesthetized rats, regional ischemia was simulated by coronary artery occlusion and then coronary blood flow was restored. The peptide G was administered intravenously (i.v.) with a bolus after a period of regional ischemia in the dose range of 0.25-3.0 mg/kg. The sizes of MI and the activities of creatine kinase-MB (СK-MB) and lactate dehydrogenase (LDH) in blood plasma were estimated. The effect of administration of the optimal dose of G (1.0 mg/kg) on myocardial content of adenine nucleotides (AN), phosphocreatine (PCr), creatine (Cr) and lactate was studied. I.v. administration of G to rats at a dose of 1.0 mg/kg slightly affected hemodynamic parameters, but reduced MI size by 40% and decreased plasma LDH and CK-MB activity by the end of reperfusion compared to control. These effects were accompanied by a significant improvement in energy state of area at risk (AAR) - an increase in myocardial content of ATP, åAN, PCr and åCr, and combined with a decrease in myocardial lactate level compared with the control. Toxicity of peptide G was studied with a single intraperitoneal injection of 0.5-3.0% solution of the peptide substance to mice. The absence of signs of intoxication and death of animals after G injection in the maximum possible dose did not allow determining the value of the average lethal dose. The results indicate therapeutic potential of the peptide G for preventing myocardial ischemia and reperfusion injury and feasibility for further study of its pharmacological properties and mechanisms of action.

Design of peptidase-resistant peptide inhibitors of myosin light chain kinase

Myosin light chain kinase (MLCK) is a key regulator of various forms of cell motility including smooth muscle contraction, cell migration, cytokinesis, receptor capping, secretion, etc. Inhibition of MLCK activity in endothelial and epithelial monolayers using cell-permeant peptide Arg-Lys-Lys-Tyr-Lys-Tyr-Arg-Arg-Lys (PIK, Peptide Inhibitor of Kinase) allows protecting the barrier capacity, suggesting a potential medical use of PIK. However, low stability of L-PIK in a biological milieu prompts for development of more stable L-PIK analogues for use as experimental tools in basic and drug-oriented biomedical research. Previously, we designed PIK1, H-(N^α Me)Arg-Lys-Lys-Tyr-Lys-Tyr-Arg-Arg-Lys-NH₂ , that was 2.5-fold more resistant to peptidases in human plasma in vitro than L-PIK and equal to it as MLCK inhibitor. In order to further enhance proteolytic stability of PIK inhibitor, we designed the set of six site-protected peptides based on L-PIK and PIK1 degradation patterns in human plasma as revealed by ¹ H-NMR analysis. Implemented modifications increased half-live of the PIK-related peptides in plasma about 10-fold, and these compounds retained 25-100% of L-PIK inhibitory activity toward MLCK in vitro. Based on stability and functional activity ranking, PIK2, H-(N^α Me)Arg-Lys-Lys-Tyr-Lys-Tyr-Arg-D-Arg-Lys-NH₂ , was identified as the most stable and effective L-PIK analogue. PIK2 was able to decrease myosin light chain phosphorylation in endothelial cells stimulated with thrombin, and this effect correlated with the inhibition by PIK2 of thrombin-induced endothelial hyperpermeability in vitro. Therefore, PIK2 could be used as novel alternative to other cell-permeant inhibitors of MLCK in cell culture-based and in vivo studies where MLCK catalytic activity inhibition is required. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

[INFLUENCE OF 29-40 AND 65-76 MCP-1 FRAGMENTS ON MYOCARDIUM MORPHOLOGY IN RATS AFTER T9CTHFMIA-R'FPFRFTTON]

Monocyte chemotactic protein-1 (MCP-1) is a chemokine that stimulates monocytes and macrophage migration into the sites of acute of chronic inflammation. Our study shows morphological changes in ischemic myocardium followed by the administration of two synthetic structural fragments of MCP-1 that are monocyte/macrophage migration inductor peptide IX and peptide X an inhibitor. Results show that peptides can change time points of the inflammatory response in myocardium. Peptide IX administration leads to increased and accelerated inflammatory response, i. e. attracts an additional number of monocytes and macrophages into the inflammatory focus. The introduction of the peptide X observed prolonged inflammatory process with the overall gain signs of myocardial damage.

[Synthetic conformational antigen, simulating the extracellular part of M2-muscarinic receptor and its reactivity with sera from patients with idiopathic arrhythmias]

Linear peptides corresponding to fragment 83-98 of the first loop and fragments 168-192 and 171-182 of the second extracellular loops of M2-muscarinic receptor (marker of early cardiac disorders and arrhythmias) were synthesized by Fmoc-SPPS method. A new conformational antigen was synthesized by method of selective ligation of linear peptides by disulfide bond with native localization. Peptides were studied in reaction with sera from patients with idiopathic arrhythmias. A new conformational antigen was recognized by sera from patients with idiopathic arrhythmias with high reactivity.

[Effect of phytic acid and its derivatives on blood lipid peroxidation state in vitro]

We have studied specific features of lipid peroxidation in whole human blood under the action of aqueous solutions of xymedone (19.6 microM), phytic acid (117.9 microM) and its complex (237.6 microM) synthesized in distilled water and isotonic (0.9%) solution of sodium chloride. The estimated parameters included lipid peroxidation (LPO) rate, total antioxidant potential, superoxide dismutase (SOD) level, and malonic dialdehyde (MDA) level in blood plasma and erythrocytes. It was established that the effect of phytic acid on blood samples includes moderate stimulation of total antioxidant activity and SOD activity with predominant prooxidant effect. The phytic acid--xymedone complex synthesized in distilled water exhibits an antioxidant action, while its synthesis in saline solution yields a prooxidant.

[Novel conformational peptide antigen, which simulates an immunodominant epitope of the 2nd extracellular loop of β1-adrenoceptor. Computer simulation, synthesis, spatial structure]

By means of computer simulation has been built polypeptide antigen conformational structure that imitates the immunodominant epitope of the 2nd extracellular loop of β1-adrenoreceptor. A linear 25-membered peptide corresponding to calculated sequence was synthesized by means of solid-phase methoyd using Fmoc-technology, then directed by the closure ofdisulfide bridges was obtained original bicyclic polypeptide corresponding to the proposed structure of the conformational antigen. With the help of high-resolution NMR spectroscopy 3D structure of synthetic conformational antigen was investigated. It was shown that the structure of the bicyclic polypeptide similar to that of building computer model. Bicyclic conformational antigen was suitable for the detection of autoantibodies in the blood serum of patients with rhythm and conductivity violation without evidence of organic disease of the cardiovascular system.

Effects of structural analogues of apelin-12 in acute myocardial infarction in rats

Objective:

To examine cardioprotective effects of Ρ-terminal fragment of adipokine apelin-12 (A12), its novel structural analogue [MeArg¹, NLe¹⁰]-A12 (I), and [d-Ala¹²]-A12 (II), a putative antagonist of APJ receptor, employing in vivo model of ischemia/reperfusion (I/R) injury.

Materials and Methods:

Peptides were synthesized by the automatic solid phase method using Fmoc technology. Anesthetized open-chest male Wistar rats were subjected to left anterior descending (LAD) coronary artery occlusion and coronary reperfusion. Hemodynamic variables and electrocardiogram (ECG) were monitored throughout the experiment. Myocardial injury was assessed by infarct size (IS), activity of necrosis markers in plasma, and metabolic state of the area at risk (AAR).

Results:

Intravenous injection of A12, I, or II at the onset of reperfusion led to a transient reduction of the mean arterial pressure. A12 or I administration decreased the percent ratio of IS/AAR by 40% and 30%, respectively, compared with control animals which received saline. Both peptides improved preservation of high-energy phosphates, reduced lactate accumulation in the AAR, and lowered CK-MB and LDH activities in plasma at the end of reperfusion compared with these indices in control. Treatment with II did not significantly affect either the IS/AAR, % ratio, or activities of both markers of necrosis compared with control. The overall metabolic protection of the AAR in the treated groups increased in the following rank: II < A12 < I.

Conclusions:

The structural analogue of apelin-12 [MeArg¹, NLe¹⁰]-A12 may be a promising basis to create a new drug for the treatment of acute coronary syndrome.

[The influence of inhibiting no formation on metabolic recovery of ischemic rat heart by apelin-12]

Apelin 12 (A-12) was synthesized by the automatic solid phase method with use of Fmoc 1H-NMR spectroscopy and mass spectrometry. Effects of apelin-12 (a peptide comprised of 12 aminoacids, A-12) on recovery of energy metabolism and cardiac function were studied in isolated working rat hearts perfused with Krebs buffer (KB) containing 11 mM glucose that were subjected to global ischemia and reperfusion. A short-term infusion of microM 140 A-12 in KB prior to ischemia enhanced myocardial ATP, the total adenine nucleotide pool (SigmaAN = ATP + ADP + AMP) and the energy charge of cardiomyocites ((ATP + 0.5ADP)/SigmaAN) at the end of reperfusion compared with control (KB infusion) and reduced lactate content and lactate/pyruvate ratio in reperfused myocardium to the initial values. This effect was accompanied by improved recovery of coronary flow and cardiac function. Coadministration of 140 microM A-12 and 100 microM L-NAME (the nonspecific NOS inhibitor) profoundly attenuated the peptide influence on metabolic and functional recovery of reperfused hearts. The results indicate involvement of NO, formed under the peptide action, in mechanisms of cardioprotection that are tightly associated with recovery of energy metabolism in postischemic heart.

[The immune-enzyme analysis based on chimeric molecule and oligopeptide fragmentations to detect autoantibodies to beta-adrenergic receptor in patients with dilation cardiomyopathy]

The article deals with specification of technique of immune-enzyme analysis to detect autoantibodies to beta-adrenergic receptors (beta1-AP) using compound of oligopeptids representing the fragmentations of extracellular sites beta1-AP and chimeric molecule of extracellular section of receptor This technique significantly exceeds the analogues defined in publications by its sensitivity and correlation with diagnosis.

[Involvement of transcriptional factor induced by hypoxia in the neuronal mechanisms of adaptation to psychoemotional and hypoxic stress]

Using quantitative immunohistochemistry, neuronal expression of alpha-subunit of the transcriptional factor HIF-1 in hippocampus and neocortex of rats in response to pathogenic psychoemotional (model of posttraumatic stress disorder, PTSD) and hypoxic (severe hypobaric hypoxia, 180 Torr, 3 h), as well as to neuroprotective exposures to hypoxic pre- and postconditioning has been studied. Elongated overexpression of HIF-1alpha in hippocampus and neocortex of rats in response to the psychoemotional stress in PTSD paradigm, but not hypoxic stress, has been observed. Hypoxic pre- and postconditioning with mild hypobaric hypoxia (360 Torr, 2 h, 3 trials spaced at 24 h), those induced adaptation to the psychoemotional stress, abolished the elongated HIF-1alpha overexpression. Hypoxic postconditioning which improved structure and functional rehabilitation following severe hypoxic stress up-regulated HIF-1alpha expression in the brain neurons of rats survived severe hypoxia. The findings indicate that transcription factor HIF-1 is particularly involved in the processes of adaptation/ maladaptation to the action of injurious stresses, but its role depends upon the nature of stressor.

[Antioxidant properties of apelin-12 and its structural analogue in experimental ischemia and reperfusion]

Effects of apelin-12 H-Arg-Pro-Arg-Leu-Ser-His-Lys-Gly-Pro-Met-Pro-Phe-OH (A12) and its modified analogue H-(NMe)Arg-Pro-Arg-Leu-Ser-His-Lys-Gly-Pro-Nle-Pro-Phe-OH (I) on activity of antioxidant enzymes, formation of malonic dialdehyde (MDA) and generation of reactive oxygen species (ROS) were studied in ex vivo and in vivo models of myocardial ischemia and reperfusion (I/R) injury in Wistar rats. Preischemic infusion of peptide A12 or AI enhanced cardiac function recovery of isolated perfused heart and was accompanied by a marked attenuation of ROS generation detected by electron paramagnetic resonance (EPR) technique in myocardial effluent at early reperfusion compared with control. Intravenous administration (i.v.) of peptides in narcotized rats with regional myocardial ischemia limited infarct size and reduced activity of lactate dehydrogenase and MB-fraction of creatine kinase in plasma at the end of reperfusion. Treatment with peptide A12 prevented reduction or augmented activity of myocardial u/Zn superoxide dismutase, catalase and glutathione peroxidase by the end of reperfusion in both I/R models compared with control. Increased MDA content in the area at risk of rat heart in situ at the end of reperfusion was reduced to the initial value under the effect of i.v. A12 administration. Therefore, cardioprotective action of natural apelin-12 and its structural analog AI involve reduction of short-lived ROS generation and improvement of the antioxidant state of ischemic heart during reperfusion.

[The effect of mild hypobaric hypoxia regime on expression of factor induced by hypoxia in the rat neocortex]

Using quantitative immunohistochemistry, modifications of HIF-1alpha expression in neocortex of rats exposed to various modes of mild hypobaric hypoxia (MHH) (1,3 and 6 episodes) differed in their neuroprotective efficacy have been studied. It has been shown that three-trial MHH being the most effective neuroprotective mode when used as a preconditioning produces most considerable changes in HIF-1 by substantial up-regulation of its regulatory alpha-subunit expression in the rat neocortex. Present findings support the hypothesis on important roles of HIF-1 in the mechanisms of brain hypoxic tolerance induced by the hypoxic preconditioning with three-trial MHH.

[Synthesis and cardioprotective properties of apelin-12 and its structural analogs]

The apelin-12 and a number of its analogs, resistant to degradation of proteases, were synthesized by Fmoc- method of SPPS. By-products of synthesis were examined. It was found that serine hydroxyl group was sulfating during the final deprotection of apelin-12 (I) and its analogs. Sulfate moiety of Arg-protecting group transfer into hydroxyl group of Ser. Amount of by-product depends on presence of water in cleavage mixture. Furthermore, the final deprotection of amide analogs of apelin-12 (III, IV) is closed with formation of by-product--4-hydroxybenzylamide, its amount range on 20-8% on reaction mixture accordance HPLC data and also depend on composition of cleavage mixture. Effects of the synthesized peptides on recovery of cardiac function after ischemia were examined in a model of isolated perfused rat heart. Infusions of any of the peptides (I-V) before ischemia resulted in a significant improvement of contractile and pump function recovery compared to the control. Cardioptotective efficacy of the peptides increased in the following rank (I) < (II) = (III) < (IV) = (V).

[Suppression of vascular endothelium hyperpermeability by cell-permeating peptide inhibitors of myosin light chain kinase]

Novel peptides originating from the peptide inhibitor of myosin light chain kinase, L-PIK (Arg-Lys-Lys-Tyr-Lys-Tyr-Arg-Arg-Lys), have been studied for ability to attenuate the thrombin-induced hyperpermeability of endothelial cell monolayer in culture. Peptides [NalphaMeArg1]-Lys-Lys-Tyr-Lys-Tyr-Arg-(D)Arg8-Lys and H-Arg(NO2)Lys-Lys-Tyr-Lys-Tyr-Arg-Arg-Lys-NH2 (designated PIK2 and PIK4, respectively) appeared to be the most effective inhibitors of endothelial cell monolayer hyperpermebility, and surpassed other known peptide inhibitors of myosin light chain kinase derived from original L-PIK. Our results validate PIK2 and PIK4 as the leading molecules for the development of novel drugs intended to counteract pathological hyperpermeability of vascular endothelium.

[Involvement of NO-dependent mechanisms of apelin action in myocardial protection against ischemia/reperfusion damage]

Apelin 12 (A-12) was synthesized by the automatic solid phase method with the use of Fmoc technology. The synthesized peptide was purified by preparative HPLC and identified by 1H-NMR spectroscopy and mass spectrometry. Acute myocardial infarction was induced by 40-min LAD occlusion followed by 60-min reperfusion in narcotized Wistar rats. A-12 was administrated at the onset of the reperfusion at doses of 0.07, 0.35 and 0.70 micromole/kg; N(G)-nitro-L-arginine methyl ester (L-NAME), a NOS inhibitor, was applied at a dose of 10 mg/kg 10 min prior to reperfusion alone or before A-12 administration (0.35 micromole/kg); saline was used in control. The indicated A-12 doses induced a transient reduction of the arterial systolic blood pressure (ASBP) to 85, 58, and 56% of the initial level, respectively, which was accompanied by its recovery by the end of reperfusion. All A-12 doses significantly limited myocardial infarct size by 26, 40 and 33%, respectively, compared to the value in control. After administration of A-12 at dose of 0.35 micromol/kg, this effect was combined with reduction of MB-creatine kinase (MB-CK) and lactate dehydrogenase (LDH) activities in plasma at the end of reperfusion by 56 and 47%, respectively, compared to the values in control. Inhibition of NO formation by L-NAME increased SABP but did not affect myocardial infarct size compared with that in control. Coadministration of L-NAME and A-12 resulted in lesser reduction of ASBP during reperfusion than injection of A-12 alone. This intervention led to an increase in infarct size by 26% with concomitant 1.8- and 1.5-times elevation of MB-CK and LDH activities, respectively, compared to the values in the A-12 group. The results indicate that NO is involved as a mediator of the effects of A-12 on the overall protection consisting in a limitation of infarct size and reduction of postischemic cardiomyocyte membrane damage. Cardioprotective mechanisms of apelin action are discussed.

Synthetic peptide fragment (65-76) of monocyte chemotactic protein-1 (MCP-1) inhibits MCP-1 binding to heparin and possesses anti-inflammatory activity in stable angina patients after coronary stenting

OBJECTIVE AND DESIGN

The peptide from C-terminal domain of MCP-1 (Ingramon) has been shown to inhibit monocyte migration and possess anti-inflammatory activity in animal models of inflammation and post-angioplasty restenosis. Here, we investigate the effect of Ingramon treatment on blood levels of acute-phase reactants and chemokines in patients after coronary stenting and the mechanisms of Ingramon anti-inflammatory activity.

SUBJECTS

Eighty-seven patients with ischemic heart disease (IHD) who faced the necessity of coronary angiography (CA) were enrolled. In 67 patients, one-stage coronary stenting was performed; 33 of them were treated with Ingramon in addition to standard therapy. Twenty patients underwent CA only.

METHODS

High-sensitivity C-reactive protein (hsCRP) and fibrinogen blood levels were detected routinely. The chemokine concentration in plasma was measured by enzyme-linked immunosorbent assay (ELISA) or cytometric bead array-based immunoassay. Intracellular Ca(2+) levels and cell surface integrin exposure were assayed by flow cytometry. MCP-1 dimerization was studied by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). MCP-1-heparin binding was assessed with a biosensor and ELISA.

RESULTS AND CONCLUSIONS

Ingramon treatment was accompanied by less pronounced elevation of hsCRP and fibrinogen levels and decreased MCP-1 concentration in plasma in patients after coronary stenting. Ingramon had no effect on MCP-1 interaction with cell receptors or MCP-1 dimerization, but inhibited MCP-1 binding to heparin. The anti-inflammatory activity of the peptide may be mediated by an impaired chemokine interaction with glycosaminoglycans.

[Novel peptide inhibitors of the myosin light chain kinase suppress hyperpermeability of vascular endothelium]

The ability of novel cell-permeating peptide molecules derived from the peptide inhibitor of the myosin light chain kinase (MLCK) L-PIK (Arg-Lys-Lys-Tyr-Lys-Tyr-Arg-Arg-Lys) to inhibit this kinase in vitro and attenuate the thrombin-induced hyperpermeability of endothelial cell monolayer in culture has been studied. It was found that the compounds [NalphaMeArg1]-L-PIK and [Cit1]-L-PIK possess the inhibitory activity towards MLCK comparable to that of L-PIK and the ability to suppress the hyperpermeability of endothelium, whereas other modifications of L-PIK were less effective. Thus, among de novo synthesized peptides, [NalphaMeArg1]-L-PIK and [Cit1]-L-PIK demonstrate the inhibitory properties of the original peptide L-PIK and additionally surpass it by stability in blood plasma. These peptides may be used in the design of novel antiedemic drugs.

[Peptide inhibitors of myosin light chain kinase. Development of peptidase resistant analogues]

Myosin light chain kinase (MLCK) is the key regulator of various forms of cell motility including endothelial and epithelial permeability in particular. One of the potential MLCK inhibitors to be used in humans is a membrane permeable peptide H-RKKYKYRRK-NH2 (L-PIK). In present work we used solid phase peptide synthesis and Fmoc-technology to produce five modifications of L-PIK. Based on (1)H NMR analysis revealed that these peptides demonstrated improved resistance to degradation in blood plasma. One of de novo synthesized peptides, L-[MeArg(1)]PIK inhibited MLCK activity in vitro with the same efficiency as L-PIK whereas other modified peptides showed reduced inhibitory activity. D-amino acid analog of PIK was the least active inhibitor. Thus, we have demonstrated the possibility to produce an effective MLCK peptide inhibitor with increased resistance to biodegradation that is suitable for further pharmacological development.

[Effect of the anti-inflammatory peptide preparation ingramon on the blood levels of acute-phase proteins and chemokines in patients after coronary stenting]

AIM

To study the effect of the anti-inflammatory peptide preparation ingramon on the peripheral blood levels of inflammatory markers in patients with exercise-induced stable angina after coronary stenting (CS).

SUBJECTS AND METHODS

The investigation enrolled 64 patients with stable angina who had undergone coronary bypass surgery, of them 34 patients received ingramon in addition to standard therapy. The blood levels of high-sensitive C-reactive protein (hs-CRP), fibrinogen, the chemokines MCP-1, IL-8, IP-10, and MID were measured before and 1, 2, and 7 days and 1, 3, and 6 months after surgery. Twenty patients who had gone coronarography (CG) only were examined as a control group.

RESULTS

In the post CS patients receiving only standard therapy, the levels of hs-CRP and fibrinogen were much higher on days 1, 2, and 7 after surgery than in the CG patients. On day 1 following CS, the increment in hs-CRP correlated with the length of implanted stents. During ingramon therapy, the content of hs-CRP and fibrinogen was considerably lower on days 1, 2, and 7 after CS than in the control group; this trend persisted a month after surgery; there was also a reduction in MCP-1 levels within the first 24 hours after initiation of therapy. The levels of the chemokines IP-10, MIG, and IL-8 were significantly unchanged. CONCLUSION. When added to standard therapy, ingramon exerts a positive effect against risk factors for coronary heart disease (CHD) and its events. Further investigations are required to define the impact of ingramon therapy on prognosis in patients with CHD.

[Effects of exogenous apelin-12 on functional and metabolic recovery of isolated rat heart after ischemia]

Apelin 12 (A 12) was synthesized by the automatic solid phase method with the use of Fmoc technology. The synthesized peptide was purified by preparative HPLC and identified by 1H NMR spectroscopy and mass spectrometry. Effects of A 12 were studied on isolated working rat hearts perfused with Krebs buffer (KB) containing 11 mM glucose. The hearts were subjected to 35 min global ischemia followed by 30 min reperfusion. A short term infusion of A 12 in KB (35, 70, 140, 280, and 560 M) was applied prior to ischemia (A 12 I) or at onset of reperfusion (A 12 R). KB infusion without A 12 was used in control. A 12 infusion enhanced recovery of coronary flow, contractile and pump function during reperfusion with the largest augmentation of these indices in A 12 I group. Thus after infusion of 140 M A 12 recovery of coronary flow, the LVDP HR product and cardiac output were 92+/-5, 81+/-5, and 77+/-5% of the initial values, respectively, in A 12 I group, 83+/-6, 61+/-5, and 52+/-5% in A 12 R group, and 76+/-2, 42+/-2, 32+/-2% in control by the end of reperfusion. Both A 12 groups exhibited significant reduction of ischemia/reperfusion contracture compared with control. Enhanced functional recovery in A 12 I group was combined with a decrease in lactate dehydrogenase leakage in perfusate at early reperfusion (at the average by 36+/-5% compared with control, &lt;0.05). Preischemic infusion of 140 M A 12 markedly increased myocardial ATP content and twice decreased AMP accumulation at the end of reperfusion. These alterations resulted in enhanced preservation of the total adenine nucleotide pool (to 81+/-5% of the initial value vs. 66+/-3% in control, &lt;0.05) and better recovery of the energy charge potential (0.77+/-0.01 vs. 0.60+/-0.06 in control, &lt;0.005) in reperfused hearts. At the end of experiment myocardial lactate and lactate/pyruvate ratio were on average 5 fold lower in A 12 I treated hearts compared with control one and did not differ significantly from initial values. This finding implies that better restoration of energy metabolism in hearts protected with A 12 before ischemia might be attributed to ameliorated glucose oxidation during reperfusion. Therefore enhanced functional recovery of ischemic heart and lesser cell membrane damage induced by A 12 were associated with maintaining high energy phosphates, particularly ATP, in reperfused myocardium. Cardioprotective mechanisms of apelin action are discussed.

[Morphological characteristics of actinomycotic dacryocanaliculitis]

The paper presents the results of pathohistological studies of the contents of the lacrimal canaliculi and the fragments of their walls, obtained at canaliculotomy in 25 patients. This permitted 14 cases of actinomycotic dacryocanaliculitis to be identified as drusens of the ray fungus Actinomyces israelii had been found. The reactive structural changes found in the wall of the lacrimal canaliculi due to the presence of fungal infection and foreign bodies in their lumen are described. A morphological study is shown to be effective in revealing the actinomycotic etiology of dacryocanaliculitis.

[Synthesis and properties of a new conformational antigen modeling an extracellular region of beta(1)-adrenoreceptor]

Two fragments corresponding to the 125-133 and 206-218 sequences of a molecule of the beta(1) adrenoreceptor (autoantibodies to this protein are often found in patients with dilated cardiomyopathy) were synthesized by the solid phase method with the use of Fmoc technology. Two new conformational antigens were prepared by directed (regioselective) and undirected (spontaneous) formation of intramolecular and intermolecular disulfide bridges between the corresponding cysteine residues of the synthesized peptides. One of these antigens consisted of a mixture of disulfide isomers, and another antigen was an isomer with a natural arrangement of S-S bridges. Immunosorbents were obtained by immobilization of the synthesizes antigens on the bromocyanogenactivated sepharose and applied to the removal of autoantibodies in a beta(1)-adrenoreceptor from the blood plasma of patients. We demonstrated that the sorbents on the basis of the conformational antigens were more effective in comparison with those containing linear peptide precursors.

[Modification of the FF neuropeptide enhances its hypertensive effect]

Neuropeptide FF (H-Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-NH2) injected intravenously temporarily enhanced the arterial pressure (AP) and the heart rate (HR). However, its role in the regulation of blood circulation is obscure. To study the properties of the molecule, its analogue was synthesized, in which proline in position 7 was substituted with glycine, and leucine in the position 2 with norleucine. Modified neuropeptide FF (FFm) also temporarily and in a dose-dependent manner increased the AP and HR; however, the equal degree of increase was reached at doses of FFm being 5-7 times lesser as compared with the natural peptide. The application of the FFm at hemorrhagic shock excluded mortality of animals during the experiment, considerably increased the degree of AP and HR restoration in the remaining experiments, and improved the survival of animals in 24 hours. It has been found that the level of antibodies to the fragment of hFF1 receptor in the serum is lower in spontaneously hypertensive rats SHR as compared with Wistar rats, but it is increased in patients of cardiological profile as compared with donors. The findings suggest involvement of neuropeptide FF in the regulation of blood circulation; however, the precise mechanisms remain to be determined.

[Development of a new anti-inflammatory peptide preparation--inhibitor of the monocytic chemotaxic protein-1 (MCP-1)]

A new anti-inflammatory peptide X (Ingramon)--a fragment of C-terminal sequence (65-76) of MCP-1, was elaborated. In Boyden chamber assay, Ingramon inhibited migration of human monocytic cells THP-1 and peripheral blood monocytes. In vitro in blood plasma, Ingramon was stable for at least 24 hours. Ingramon was accumulated in sites of inflammation in rats, and impaired monocyte and granulocyte accumulation occurred in different models of inflammation in rodents and primates. Ingramon exerted no effect on the MCP-1-dependent externalisation of p2 integrins CD lib CD18 (Mac-1). We propose that Ingramon might interfere with MCP-1-heparin/heparan sulphate binding on cell surface. Ingramon reception by volunteers showed its safety. The clinical trials of Ingramon in patients with acute coronary syndromes and percutaneous coronary interventions, have been launched.

[Penetrating peptide inhibitor of the myosin light chain kinase suppresses hyperpermeability of vascular endothelium]

Nonapeptide H-Arg-Lys-Lys-Tyr-Lys-Tyr-Arg-Arg-Lys-NH2 corresponding to a modified sequence of autoinhibitory region of myosin light chain kinase (MLCK) was synthesized from L-amino acids and from D-amino acids. Using nuclear magnetic resonance spectroscopy it has been demonstrated that D-peptide is significantly more stable in human blood plasma than its L-enantiomer. D-peptide accumulated in cultured human umbilical vein endothelial cells suppressed development of hyperpermeability in endothelial monolayer induced by thrombin addition. Following intravenous administration D-peptide decreased the extent of lung oedema in rats induced by infusion of oleic acid in bloodstream. Thus, the peptide molecules based on an autoinhibitory peptide of MLCK may serve as a prototype for development of a novel antioedematous drugs that directly affect the MLCK-dependent motile processes in vascular endothelium.

Effects of synthetic monocyte chemotactic protein-1 fragment 65-76 on neointima formation after carotid artery balloon injury in rats

The effects of the synthetic monocyte chemotactic protein-1 (MCP-1) peptide fragment 65-76 (peptide X) on the development of neointima after balloon injury to the carotid artery were studied. The agent was given i.m. at a dose of 33 microg/kg once daily for 28 days after balloon injury. Animals given peptide showed significant suppression of neointima growth 4 and 7 days after lesioning, as indicated by morphometric analysis of sections of lesioned arteries. On days 14 and 28, there were no significant differences in neointima formation in rats given and not given peptide. Peptide administration was not accompanied by any changes in C-reactive peptide concentrations, leukocyte counts, or the population composition of peripheral blood lymphocytes. Use of synthetic peptide X as an inhibitor of leukocyte migration during angioplasty may, along with traditional treatments, decrease the risk of restenosis.

Novel phosphospecific antibodies for monitoring phosphorylation of proteins encoded by the myosin light chain kinase genetic locus

Myosin light chain kinase (MLCK) and the kinase-related protein (KRP), also known as telokin, are the major independent protein products of the smooth muscle/non-muscle MLCK genetic locus. They share a common C-terminal part and major sites phosphorylated in vivo. Whereas MLCK is critically involved in myosin activation and contraction initiation in smooth muscle, KRP is thought to antagonize MLCK and to exert relaxation activity. Phosphorylation controls the MLCK and KRP activities. We generated two phosphorylation and site-specific antibodies to individually monitor levels of MLCK and KRP phosphorylation on critical sites. We quantified the level of KRP phosphorylation in smooth muscle before and after an increase in intracellular free Ca2+ and stimulation of adenylate cyclase, protein kinase C, and mitogen-activated protein kinases (MAP-kinases). Forskolin and phorbol-12,13-dibutyrate increased KRP phosphorylation at Ser13 from 25 to 100% but did not produce contraction in rat ileum. The level of Ser13 phosphorylation was not altered during Ca2+-dependent contraction evoked by KCl depolarization or carbachol, but subsequently increased to maximum during forskolin-induced relaxation. These data suggest that several intracellular signaling pathways control phosphorylation of KRP on Ser13 in smooth muscle and thus may contribute to relaxation. In contrast, phosphorylation level of Ser19 of KRP increased only slightly (from 30 to 40-45%) and only in response to MAP-kinase activation, arguing against its regulatory function in smooth muscle.

[The effect of synthetic fragment 65-76 of monocyte chemiattractant protein-1 (MCP-1) on neointima growth after carotid artery balloon injury in rats]

Influence of synthetic fragment 65-76 of monocyte chemoattractant protein-1 (MCP-1) (peptide X) on development of neointima after balloon injury of carotid artery was investigated. Peptide X was introduced intramuscularly, 33 pg/kg, daily during 28 days after balloon injury. In days 4 and 7 after intervention, in animals receiving peptide X in comparison with control animals a substantial decrease of neointimal growth was observed. On 14 and 28 days there, was no significant difference in neointima development in rats with and without peptide treatment. Injections of peptide X did not after the C-reactive protein concentration, leukocyte number and lymphocyte subpopulations in peripheral blood. Peptide X treatment along with traditional therapy may be effective in preventing restenosis after angioplasty.

The peptide analogue of MCP-1 65-76 sequence is an inhibitor of inflammation

Inflammation plays an important role in vessel wall remodeling that occurs in atherosclerosis and postangioplasty restenosis. Monocytic chemoattractant protein-1 (MCP-1) is one of the main attractors of monocytes and some lymphocyte subsets to the damaged vessel. The aims of the study were to confirm MCP-1 participation in the development of acute coronary syndromes, to produce the potential MCP-1 peptide antagonist, and to investigate its effects in vitro and in vivo in different animal models of inflammation. MCP-1 plasma concentration was measured by ELISA (enzyme-linked immunosorbent assay). Chemokine receptor expression by cells isolated from human atherosclerotic lesions was assessed by direct immunofluorescence and flow cytometry. MCP-1 sequence was analyzed with Peptide Companion software and peptides were synthesized using Fmoc strategy. The peptide resistance to degradation was checked by 1H-NMR spectroscopy. The peptide effect on MCP-1-stimulated cell migration was studied in Boyden chamber and in mouse air pouch model, and its influence on lipopolysaccharide (LPS)-induced inflammatory cell recruitment was investigated in models of subcutaneous inflammation in rats and nonhuman primates. We revealed nearly a 2-fold increase of MCP-1 plasma level in patients with unstable angina in comparison with patients with stable angina. The atherosclerotic plaque specimens obtained from patients with unstable angina contained a significant amount of chemokine receptor-expressing leukocytes. Peptide from MCP-1 C-terminal 65-76 sequence (peptide X) inhibited MCP-1-stimulated monocytic cell migration in vitro and in vivo. Peptide X labeled with 99mTc accumulated specifically at sites of inflammation in rats. Peptide X administrated i.m and i.v. suppressed monocyte and granulocyte recruitment induced by subcutaneous injection of LPS in the back of rats and non-human primates. Our data demonstrate that MCP-1-mediated chemotaxis could be responsible for atherosclerotic plaque "destabilization". Peptide X may represent a new class of anti-inflammatory drugs to be used in cardiology.

[Imaging of inflammatory foci with 99m technecium labeled antimicrobial oligopeptide]

A direct method using 99mtechnecium to label the synthetic antimicrobial oligopeptide ubiquicidine with a molecular mass of 1.7 kDa has been developed. The radiochemical purity of the resultant labeled compound was more than 98%. A combination of ubiquicidine and 99mtechnecium showed stability in blood plasma. The biological study indicated that the complex was renally excreted from blood flow rapidly (the half-life is 30 min). It accumulated in the experimental inflammatory focus of laboratory animals, peaking 1-2 hours after intravenous injection when the inflammatory focus/intact tissue ratio amounted up to 2.6-3.4, which could yield satisfactory abscess scintigrams. The findings make it possible to consider ubiquicidine as a promising compound for the design of radiopharmaceutical to image inflammatory foci.

[Peptide fragment 66-77 of monocyte chemoattractant protein 1 and its retro-enantio analogue inhibits the migration of cells in vitro and in vivo]

The retro-enantio analogue of peptide 66-77 of the chemokine MCP-1 and two hexapeptide fragments 66-71 and 72-77 of the C-terminal sequence of this protein were synthesized using the Fmoc strategy of solid phase peptide synthesis. The effect of the synthetic peptides upon the MCP-1-stimulated migration of THP-1 mononuclear cells was studied in vitro. The activity of the retro-enantio analogue was found to be comparable with that of the initial peptide 66-77: both peptides inhibit the migration of monocytes and granulocytes into inflammation zones of experimental animals.

[The synthesis of immunomodulating peptide alloferon, the active component of the antiviral drug allokine-alpha]

Two variants of the synthesis of tridecapeptide alloferon, the active principle of antiviral preparation allokine-alpha, were developed on the basis of fragment condensation in solution or on the Merrifield resin. The solid phase variant of the synthesis was shown to be more technological; it allows the preparation of the product at a higher total yield (40% vs. 17% for conventional synthesis in solution from the starting derivatives of the C-terminal dipeptide). The by-products formed during the synthesis of alloferon were identified.

[Use of hydrogen peroxide for closing disulfide bridges in peptides]

The use of hydrogen peroxide for the formation of disulfide bridges was studied in 15 peptides of various lengths and structures. The oxidation of peptide thiols by hydrogen peroxide was shown to proceed under mild conditions without noticeable side reactions of Trp, Tyr, and Met residues. Yields of the corresponding cyclic disulfides were high and mostly exceeded those obtained with other oxidative agents, in particular, iodine. It was established that the use of hydrogen peroxide in organic medium also provided sufficiently high yields when large-scale syntheses of oxytocin and octreotide (up to 10 g) were carried out. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 2; see also http://www.maik.ru.

[Contents of T-lymphocytes and expression of intercellular adhesion molecule ICAM-1 in the retina and choroid in diabetic retinopathy]

The authors analyze the relationships between individual immune components at a cellular level and evaluate their significance in development of proliferative processes. Ocular tissues from diabetics who died from cardiovascular failure and stroke and from subjects who died from traumas (control) were examined by immunohistochemical methods. The results evidence increased counts of T lymphocytes and high expression of ICAM-1 in ocular tissues of diabetics, which suggests an important role of these factors in development of diabetic retinopathy.

Hydrogen peroxide for disulfide bridge formation in methionine-containing peptides

Two methionine-containing peptides, endothelin 1 and the 1-16 fragment of the receptor of the plasminogen activator 1 for human urokinase, were synthesized and cyclized by hydrogen peroxide. Endothelin 1 was obtained by using regioselective and random schemes of disulfide bond formation. The conditions of cyclization that provided the target products in high purity were found. The general potential of disulfide bond formation by means of hydrogen peroxide was demonstrated for methionine-containing peptides. The method resulted in target products containing insignificant quantities of the corresponding Met-sulfoxide derivatives.

[Antibodies against synthetic peptide fragments of T-cadherin inhibit binding of low density proteins with T-cadherin]

Potential antigenic determinants of the atypical lipoprotein-binding proteins T-cadherin (p105) and its precursor (p130) from cells of human smooth muscles were synthesized by the solid phase method according to the Fmoc-scheme. These corresponded to the 51-61, 140-160, 161-179, 260-271, 340-352, 350-362, and 370-385 sequences of p130 and were chosen on the basis of computer analysis of its antigenic structure. The conjugates of the peptides with horseradish peroxidase were used for the immunization of mice and rabbits. Antisera against the peptides corresponding to the 140-160, 161-179, and 260-271 sequences of p105 were shown by immunoblotting to react with p105, which we isolated from the vascular cells of smooth muscles and earlier identified as T-cadherin. These antisera inhibited the binding of low density lipoproteins with p105 in a dose-dependent manner. These results confirmed the identification of the p105 protein as T-cadherin and demonstrated the fundamental possibility of studying the interaction of this protein with low density lipoproteins by using antipeptide antibodies that inhibit binding.

[Directed and spontaneous disulfide bond closure using hydrogen peroxide in the synthesis of endothelins-1 and -3]

The linear precursors of endothelin 1 and endothelin 3, natural vasoactive peptides, were obtained by using the Boc- and Fmoc-schemes of solid phase peptide synthesis. The methods of directed and spontaneous formation of two disulfide bonds in the molecules of these precursors were compared and shown to give comparable results. The conditions were found that provided the selective S-S-ring closure in the methionine-containing endothelin 1 by means of hydrogen peroxide without the undesired conversion of the Met residue into the corresponding sulfoxide.