Peptide Blocker of Ion Channel TRPV1 Exhibits a Long Analgesic Effect in the Heat Stimulation Model.

The ion channel TRPV1, which is one of the most important integrators of pain and inflammatory stimuli, is considered a promising therapeutic target in the treatment of pain conditions. In this work, we performed a comparative study of the analgesic effect in the "hot plate" test of recombinant analogues of Kunitz-type peptides from the sea anemone Heteractis crispa venom: APHC1-modulator of TRPV1 and HCRG21-a full blocker of TRPV1. As a result of biological tests, it was shown that the full blocker HCRG21, despite the higher value of 50% effective concentration of TRPV1 inhibition, had an equal analgesic ability with the APHC1 upon intramuscular administration and retained it for 13 h of observation. The analgesic effect of APHC1 at a dose of 0.1 mg/kg when administered intramuscularly developed very quickly in 5 min but lasted 3 h. The differences in the pharmacodynamic profile of the peptides are in good agreement with different mechanisms of binding to TRPV1.

TRPA1 Channel as a Regulator of Neurogenic Inflammation and Pain: Structure, Function, Role in Pathophysiology, and Therapeutic Potential of Ligands.

TRPA1 is a cation channel located on the plasma membrane of many types of human and animal cells, including skin sensory neurons and epithelial cells of the intestine, lungs, urinary bladder, etc. TRPA1 is the major chemosensor that also responds to thermal and mechanical stimuli. Substances that activate TRPA1, e.g., allyl isothiocyanates (pungent components of mustard, horseradish, and wasabi), cinnamaldehyde from cinnamon, organosulfur compounds from garlic and onion, tear gas, acrolein and crotonaldehyde from cigarette smoke, etc., cause burning, mechanical and thermal hypersensitivity, cough, eye irritation, sneezing, mucus secretion, and neurogenic inflammation. An increased activity of TRPA1 leads to the emergence of chronic pruritus and allergic dermatitis and is associated with episodic pain syndrome, a hereditary disease characterized by episodes of debilitating pain triggered by stress. TRPA1 is now considered as one of the targets for developing new anti-inflammatory and analgesic drugs. This review summarizes information on the structure, function, and physiological role of this channel, as well as describes known TRPA1 ligands and their significance as therapeutic agents in the treatment of inflammation-associated pain.

Generation of high-intensity spectral supercontinuum of more than two octaves in a water jet.

In this paper, we demonstrate experimentally for the first time (to our knowledge) the generation of spectral supercontinuum (SC) of more than two octaves with high intensity in a water jet. The spectrum of the generated SC extends from 350 to 1400 nm, with intensities up to 1011 W/cm2, and its generation efficiency is more than 50%. For the pump intensity 3.0×1012 W/cm2 in the spectral range from 400 to 800 nm, the spectrum is nearly flat (less than 40% deviation), which is useful for many applications.

[Regional intraosseous thrombolytic therapy in comprehensive treatment of patients with diabetic foot syndrome]. / Regionarnaia vnutrikostnaia tromboliticheskaia terapiia v kompleksnom lechenii sindroma diabeticheskoi stopy.

The authors assessed efficacy of regional intraosseous administration of urokinase medac in comprehensive treatment of patients with complicated forms of diabetic foot syndrome by means of analysing therapeutic results in a total of 65 patients presenting with pyonecrotic complications of diabetic foot. The patients were subdivided into 2 groups. The control group was composed of 35 patients receiving basic therapy. The study group comprised 30 patients subjected to comprehensive treatment including regional intraosseous (into the heel bone of the affected limb) administration of urokinase medac at a dose of 100 thousand IU for 5 days. Efficacy of treatment was evaluated by the course of the wound process, indices of haemostasis, free radical oxidation, results of surgical treatment. In patients of the Study Group the terms of wound purification from pyonecrotic masses amounted to 9.8±0.3 days, which was by 4.7 days less than in the Control Group patients (p<0.01), marginal epithelialization of wounds also occurred averagely by 6.4 days faster. On day 22 of using the basic therapy alone, the haemostasis system preserved the condition of coagulation activity. The Study Group patients as early as on day 5 of treatment demonstrated shifts towards normocoagulation. In the Control Group by day 22 of treatment, the level of malonic dialdehyde decreased by 18.5%, the index of catalase activity increased by 24.6% (p<0.05); in the Study Group the level of malonic dialdehyde decreased by 42.6% and catalase activity increased by 69.4% (p<0.01). On the background of using urokinase the number of high amputations decreased by 18% and the number of operations with the supporting function preserved decreased by 12% as compared with basic therapy alone. A conclusion was made that additional use of regional intraosseous administration of urokinase medac as compared with basic therapy alone promoted a more significant decrease in the coagulation activity of blood and the level of free-radical lipid oxidation, stimulation of regenerative processes, as well as improvement of outcomes of surgical treatment.

Secure polarization-independent subcarrier quantum key distribution in optical fiber channel using BB84 protocol with a strong reference.

A quantum key distribution system based on the subcarrier wave modulation method has been demonstrated which employs the BB84 protocol with a strong reference to generate secure bits at a rate of 16.5 kbit/s with an error of 0.5% over an optical channel of 10 dB loss, and 18 bits/s with an error of 0.75% over 25 dB of channel loss. To the best of our knowledge, these results represent the highest channel loss reported for secure quantum key distribution using the subcarrier wave approach. A passive unidirectional scheme has been used to compensate for the polarization dependence of the phase modulators in the receiver module, which resulted in a high visibility of 98.8%. The system is thus fully insensitive to polarization fluctuations and robust to environmental changes, making the approach promising for use in optical telecommunication networks. Further improvements in secure key rate and transmission distance can be achieved by implementing the decoy states protocol or by optimizing the mean photon number used in line with experimental parameters.

[Structural Features of Cysteine-Stabilized Polypeptides from Sea Anemones Venoms].

Nowadays, venom-based drug discovery becomes popular again: pharmaceutical companies evaluate animal venom potential as a combinatory library of biologically-active compounds. Collaborations with research groups from academia are intensified, new toxins are being investigated, among which polypeptides are of paramount importance. Sea anemones produce the most diversified, from structural point of view, polypep- tide venom components among other animals. This particular review considers known polypeptide toxins from sea anemones, basically taking into account its classification by primary structural features. The most important functional characteristics are analyzed in each structural class.

[The Biological Activity of the Sevanol and Its Analogues].

Previously, from the plant Thymus armeniacus a new lignan sevanol was isolated, it's structure was elucidated and was shown that it effectively inhibits the acid-sensing channel ASIC3 and also exhibits a pronounced analgesic and anti-inflammatory effect. In this work biological activity of the sevanol analog obtained by chemical synthesis from simple precursors, the stereoisomer of sevanol and a precursor molecule represents a half of sevanol was measured in electrophysiological experiments on human ASIC3 channels expressed in Xenopus laevis oocytes. Measured inhibitory activity of a synthetic analogue coincided with the activity ofthe natural molecule. Stereoisomer showed inhibitory activity drop by about a third part, and the precursor molecule showed much less significant activity. In result the significance of functional groups and a spatial configuration of sevanol in order to biological activity was shown that is important to take into account for the optimal synthesis design as well as for new drugs development on its base.

Acid-sensing ion channels and their modulators.

According to a modern look acid-sensing ion channels (ASICs) are one of the most important receptors that perceive pH change in the body. ASICs represent proton-gated Na+-selective channels, which are expressed in neurons of the central and peripheral nervous system. These channels are attracting attention of researchers around the world, as they are involved in various physiological processes in the body. Drop of pH may occur in tissues in norm (e.g. the accumulation of lactic acid, the release of protons upon ATP hydrolysis) and pathology (inflammation, ischemic stroke, tissue damage and seizure). These processes are accompanied by unpleasant pain sensations, which may be short-lived or can lead to chronic inflammatory diseases. Modulators of ASIC channels activity are potential candidates for new effective analgesic and neuroprotection drugs. This review summarizes available information about structure, function, and physiological role of ASIC channels. In addition a description of all known ligands of these channels and their practical relevance is provided.

Experimental substantiation of the efficiency of antioxidant therapy for post-traumatic arthritis.

Experimental post-traumatic arthritis was accompanied by overexpression of pro-inflammatory cytokines and imbalance in the collagen metabolism. Intraarticular injection of mexidol prevented free-radical degradation of collagen structures, contributed to activation of collagen synthesis and cartilage repair, and reduced the severity of inflammatory changes in the joint and the degree of secondary alteration of tissue structures.

A novel cysteine-rich antifungal peptide ToAMP4 from Taraxacum officinale Wigg. flowers.

A novel peptide named ToAMP4 was isolated from Taraxacum officinale Wigg. flowers by a combination of acetic acid extraction and different types of chromatography: affinity, size-exclusion, and RP-HPLC. The amino acid sequence of ToAMP4 was determined by automated Edman degradation. The peptide is basic, consists of 41 amino acids, and incorporates three disulphide bonds. Due to the unusual cysteine spacing pattern, ToAMP4 does not belong to any known plant AMP family, but classifies together with two other antimicrobial peptides ToAMP1 and ToAMP2 previously isolated from the dandelion flowers. To study the biological activity of ToAMP4, it was successfully produced in a prokaryotic expression system as a fusion protein with thioredoxin. The recombinant peptide was shown to be identical to the native ToAMP4 by chromatographic behavior, molecular mass, and N-terminal amino acid sequence. The peptide displays broad-spectrum antifungal activity against important phytopathogens. Two ToAMP4-mediated inhibition strategies depending on the fungus were demonstrated. The results obtained add to our knowledge on the structural and functional diversity of AMPs in plants.

[Polypeptide toxin from sea anemone inhibiting proton-sensitive channel ASIC3].

Polypeptide toxin pi-AnmTX Hcr 1b-1 with a molecular weight 4537 Da was isolated from the whole body extract of sea anemone by a multistage liquid chromatography. The BLAST search algorithm revealed homology of the novel toxin amino acid sequence to the group of the known sea anemone toxins including BDS and APETx with similarity less then 50%. The toxin pi-AnmTX Hcr 1b-1 inhibited the amplitude of the fast component of integral ASIC3 current in electrophysiological studies on receptors expressed in Xenopus laevis oocytes. The calculated IC50 value was 5.5 +/- 1.0 microM. Among the known polypeptide toxins interacted with ASICs channels, the micro-AnmTX Hcr 1b-1 toxin is the least potent inhibitor that in our opinion correlates with a small amount of charged amino acid residues in its structure.

[Comparison of polypeptide compositions from individual Agelena orientalis spider venoms].

Spider venoms are peculiar combinatory libraries of polypeptide molecules that specifically affect various cell targets. However, the question has remained up to now regarding whether the observed diversity of the polypeptides results from the synthesis of the complete library of these molecules by each individual spider or is due to the peculiarity of each zooid producing a limited set of components. We studied the composition of the mixed venom taken from several dozens of zooids of the Central Asian species of the Agelena orientalis and compared it with the venoms of 20 individual spiders of this species. The venoms were qualitatively and quantitatively analyzed by HPLC, mass spectrometry, and amino acid sequencing. It was shown that the individual venoms contain a lesser number of polypeptide components in comparison with the mixed venom and, in addition, differ from each other by the component composition. The set of components produced by single zooids is relatively narrow, and on the whole is a set identical to that of the mixed venom. The polypeptides with a high content in the venom were structurally characterized and compared with the amino acid sequences deduced from the cDNA library of this species.

Molecular diversity of spider venom.

Spider venom, a factor that has played a decisive role in the evolution of one of the most successful groups of living organisms, is reviewed. Unique molecular diversity of venom components including substances of variable structure (from simple low molecular weight compounds to large multidomain proteins) with different functions is considered. Special attention is given to the structure, properties, and biosynthesis of toxins of polypeptide nature.

[New polypeptide components from the Heteractis crispa sea anemone with analgesic activity].

Two new polypeptide components which exhibited an analgesic effect in experiments on mice were isolated from the Heteractis crispa sea tropical anemone by the combination of chromatographic methods. The APHC2 and APHC3 new polypeptides consisted of 56 amino acid residues and contained six cysteine residues. Their complete amino acid sequence was determined by the methods of Edman sequencing, mass spectrometry, and peptide mapping. An analysis of the primary structure of the new peptides allowed for their attribution to a large group of trypsin inhibitors of the Kunitz type. An interesting biological function of the new polypeptides was their analgesic effect on mammals, which is possibly realized via the modulation of the activity of the TRPV1 receptor and was not associated with the residual inhibiting activity towards trypsin and chymotrypsin. The analgesic activity of the APHC3 polypeptide was measured on the hot plate model of acute pain and was significantly higher than that, of APHC2. Methods of preparation of the recombinant analogues were created for both polypeptides.

[Mechanisms of formation of chronic low back pain relapse and their correction in patients with dorsopathy].

A clinical-neurological, psychological, biochemical and electromyographic study of 40 operated and 40 non-operated patients with chronic low back pain syndrome was conducted before and after treatment. The authors used various modes of administration of xydifonum, a chelate from the group of bisphosphonates, including electrophoretic, peroral and administration in the form of ointment, administered in turn with heparin one to improve the antiplatelet effect, using photopheresis the with the help of the state-of-the art photomatrix LED equipment. The application of Ca2+-modulating properties of xydifonum demonstrate its universality in achieving of analgesic, muscle-relaxing, anxiolytic and antidepressant effects thus allowing to exclude polypragmasy. This is a main difference between this drug and other medications with limited effects. Based on the results obtained, the authors propose a scheme of development of chronic low back pain.