[Adamantan derivatives capable of inhibiting the reproduction of a Rimantadine resistant strain of influenza A(H1N1)pdm09 virus (Influenza A virus, Alphainfluenzavirus, Orthomyxoviridae).]

INTRODUCTION: Adamantanthane-type drugs such as rimantadine and amantadine have long been used to treat diseases caused by influenza A virus. However, as a result of the mutations, influenza viruses have become resistant to aminoadamantans. The target for these drugs was the protein channel M2. Influenza A virus M2 viroporin in the protein shell forms fairly specific ion channels with a diameter of about 11 Å, specializing in transporting protons inside the viral particle (virion). Restoration of the antiviral properties of adamantanthane-type drugs consists in the selection of advanced functional groups bound by the carbocycle to find new sites of binding to the protein target M2. The purpose of the study is to identify the antiviral properties of new adamantanum derivatives to the pandemic strain of influenza A virus in vitro. MATERIAL AND METHODS: Compounds of aminoadamantans with amino acids and other organic molecules were obtained by classical peptide synthesis methods. The structure of the compound was tested by means of physical and chemical methods. Antiviral properties of synthetic compounds were studied in vitro on monolayer MDCK cells infected with pandemic strain of influenza A/California/07/2009 virus in two schemes of administration of investigated compounds and virus. RESULTS: The reference strain of the influenza virus A/California/07/2009(H1N1) was sensitive to the compounds under test in varying degrees. The antiviral activity of the compounds was expressed in a 50% inhibitory concentration (IС50) ranging from 0.5 to 2.5 мкM, which is generally a good indicator for the Rimantadine/Amantadine resistant strain. DISCUSSION: The values of the IС50 for compounds introduced two hours before contact with the virus were slightly higher than those for single-moment introduction of the substance and virus. The effect of increasing the inhibitory concentration in the prophylactic scheme of compounds was valid for all compounds of the experiment. CONCLUSION: The presented synthetic compounds are active against the variant of influenza A virus resistant to Rimantadine and Amantadine preparations. The obtained compounds can be used as model structures for creation of a new drug of direct action against advanced strains of influenza A virus.

[Assessment of the antiviral activity of 2HCl*H-His-Rim compound compared to the anti-influenza drug Arbidol for influenza caused by A/duck/Novosibirsk/56/05 (H5N1) (Influenza A virus, Alphainfluenzavirus, Orthomyxoviridae).]

INTRODUCTION: The emergence of influenza virus strains with drug resistance to antiviral drugs requires finding new compounds, potential direct-acting inhibitors. Аdamantane compounds drugs used since the 1960s have lost their activity the resulting due to resistance. Only neuraminidase inhibitors such as zanamivir and oseltamivir have been approved by WHO for influenza treatment. The Russian pharmaceutical drug Arbidol (Umifenovirum) is actively used in Russia. This drug is used to treat influenza in Russia, China and most post-Soviet republics. This work presents a new derivative of aminoadamantane - dichlorohydrate L-histidyl-1-adamantayl ethylamine (2HCl*H-His-Rim), which showed a high level of inhibition of strains of influenza virus A in vitro. OBJECTIVES: Comparison of antiviral properties of the new synthetic low-molecular inhibitor of influenza A virus replication and Arbidol drug pharmacy. METHODS: The compound 2HCl*H-His-Rim was obtained by classical peptide synthesis methods. It was identified by methods of mass spectrometry, infrared spectroscopy (IR) and nuclear magnetic resonance spectroscopy (NMR). Its antiviral properties have been studied in vitro for monolayer of cells Vero-E6 infected with a high-virulent strain of A/duck/Novosibirsk/56/06 (H5N1) influenza virus at various injection schemes of the investigated compounds. THE RESULTS: The antiviral activity of the 2HCl*H-His-Rim compound against the highly pathogenic strain of the influenza A/H5N1 virus was slightly higher than for the known pharmacy drug arbidol. DISCUSSION: The difference in antiviral activity of these two compounds is explained by different mechanisms of action on the viral particle. CONCLUSION: The 2HCl*H-His-Rim compound can be recommended as a candidate for preclinical and clinical trials in order to obtain an etiotropic antiviral drug based on it, due to its high efficacy and economic and synthetic availability. The synthetic compound 2HCl*H-His-Rim acts on influenza A virus variants resistant to Rimantadine and Amantadine.

New Carbocyclic Amino Acid Derivatives Inhibit Infection Caused by Highly Pathogenic Influenza A Virus Strain (H5N1).

New amino acid derivatives with carbocycles of adamantine and quinaldic acid were synthesized and their in vitro antiviral activity against influenza A/H5N1 virus was evaluated. Experiments on cultured embryonic porcine kidney epithelial cells showed that amino acid derivatives suppressed viral replication. Tret-butyloxycarbonyl-DL-methionylsulfonyl-1-adamantayl ethylamine and benzyloxycarbonyl-L-trypthophanyl-1-adamantayl ethylamine compounds demonstrated high activity in all in vitro experiments. Moreover, some compounds showed virucidal activity against influenza A/H5N1 virus.

[Antiviral activity of aqueous extracts of the birch fungus Inonotus obliquus on the human immunodeficiency virus].

Fractions of aqueous and water-alcohol extracts of the birch fungus Inonotus obliquus have antiviral effect against the human immunodeficiency virus type 1 (HIV-1). Antiviral properties of low toxic extracts were manifested in the concentration of 5.0 µg/ml upon simultaneous application with the virus in the lymphoblastoid cells culture MT-4. The extract of the birch fungus can be used for development of new antiviral drugs, inhibitors of HIV-replication when used both in the form of individual drugs and as a part of complex therapy.

[A study of the antiherpetic activity of the chaga mushroom (Inonotus obliquus) extracts in the Vero cells infected with the herpes simplex virus].

The chaga mushroom (Inonotus obliquus) contains a wide range of excellent bioactive compounds. However, limited information exists on the antiviral activity of the compounds extracted from chaga. A number of subfractions of chaga were obtained using different solvents and different procedures. The subfractions of chaga extracted with water, alcohol, alkali were tested for their toxicity for the Vero cell culture and antiviral effect in the Vero cells infected with the Herpes simplex virus (HSV), Type 1. It was shown that most of the subfractions were not toxic for the Vero cells and had protective effect on the Vero cells infected with HSV. The subfraction IV in the concentration 5 microg/ml protected the Vero cells from cytodestructive action of HSV and no viral DNA was detected in infected cells treated with chaga extracts. Best protective effect was observed when compound was added before or within one hour after the Vero cells were infected with HSV.

Amino acid derivatives of adamantane carbocycle are capable of inhibiting replication of highly virulent avian influenza A/H5N1 virus.

We studied the capacity amino acid derivatives of adamantane to inhibit replication of highly virulent avian influenza A/duck/Novosibirsk/56/05 (H5N1) virus in cultures of swine embryonic kidney cells. Amino acid derivatives of adamantane H-His-Rem and Ad(CH2-Ser-OMe)2 were characterized by lower toxicity than remantadine previously used in the treatment of influenza. Histidine-containing adamantane derivative (H-His-Rem) was the most effective and low-toxic inhibitor of influenza А/H5N1 virus replication and can be recommended for clinical trials to produce a preparation for the treatment and prevention of influenza.

New adamantane derivatives can overcome resistance of influenza A(H1N1)pdm2009 and A(H3N2) viruses to remantadine.

New adamantane derivatives with amino acid residues and other bifunctional compounds were synthesized and their antiviral activity towards influenza A(H1N1)pdm and A(H3N2) viruses was studied. Some of these adamantane derivatives completely suppressed replication of remantadine-resistant influenza A virus strains.

[New adamantane derivatives and ways of overcoming the resistance of influenza A viruses to rimantadine and amantadine].

The amino acid and peptide derivatives of 1-adamantane carboxylic acid and rimantadine (18 compounds) have been first synthesized and investigated for their activity against influenza A virus (H1N1, H1N1v). In a series of obtained adamantine derivatives, some compounds have been found to be able to inhibit rimantadine-resistant influenza A virus strains. Thus, the antiviral properties of rimantadine can be restored.

[Antibody responses to consensus sequence of hypervariable region 1 from hepatitis C virus protein E2 in relation to the phase of infection].

Three overlapping peptides containing linear B-cell epitopes and corresponding to the consensus sequence of hypervariable region 1 (HVR1) from protein E2 were studied for their capacity to interact with the sera from patients with acute and chronic hepatitis C. Antibodies to these peptides are detectable with the comparable frequency in both acute and chronic hepatitis C viral infection, other than after viral elimination. A relationship of the outcome of acute Infection to the presence or absence of antibodies to the test peptides has not been established. The level of antibodies against protein E2 HVR1 C-terminus is significantly higher in chronic hepatitis C.

[Detection of type specific antibodies to hepatitis C virus NS4 protein in hepatitis C patients by enzyme immunoassay]. / Vyiavlenie tipospetsificheskikh anti-HCNS4-antitel u bol'nykh gepatitom C metodom immunofermentnogo analiza.

A multi-enzyme immmune-assay test system was designed for serotyping of genotypes hepatitis C virus (HCV) and a method of such typing of the serum of patients with hepatitis C was worked out. The above test-system was worked out on the basis of a study of 10 type-specific peptides modeling different fragments from NS4-protein variable region of HCV. The designed test system was evaluated by using a set of 42 serum samples obtained at random from patients with chronic hepatitis C, which had been preliminarily genotyped by polymerase chain reaction. The serotyping makes it possible to identify the type-specific antibodies in the blood sera of patients, including those cases when viremia was absent. Differences in the circulation of HCV in Moscow (Russia) and Vitebsk (Byelorussia) were established by using the designed test-system.

[Spectrum of antibodies to HCV antigens in patients with different clinical patterns of chronic HCV infection]. / Spektr antitel k razlichnym antigenam HCV pri raznykh variantakh techeniia khronicheskoi HCV-infektsii.

Correlations between the spectra of antibodies to HCV proteins represented by various antigenic determinants and clinical variants of chronic HCV infection were studied. Synthetic peptides core-16, NS4-20, and NS5-23 simulating the immunodominant regions of the core, NS4 and NS5 proteins and recombinant proteins core-114 and NS4-86 were used as antigens. The results indicate that if the serum of an HCV patients contains no IgG to both antigenic determinants of NS4 or to NS5 in combination with any core antigenic determinant, a clinical and biochemical remission is highly probable. Chronic hepatitis C is characterized by the presence of IgG in high titers to both antigenic determinants of NS4 protein, particularly in combination with anti-NS5 IgG in low titers or none at all, or high titers of anti-core-16 IgG in combination with high titers of anti-NS4-20 IgG.

[Diagnostic significance of antibody detection to various hepatitis C virus antigens in patients with acute and chronic HCV-infection]. / Diagnosticheskaia znachimost' opredeleniia antitel k razlichnym antigenam virusa gepatita C u patsientov s ostroi i khronicheskoi HCV-infektsiei.

AIM: To examine diagnostic value of antibodies to various HCV antigens in patients with acute and chronic HCV-infection. MATERIAL AND METHODS: Enzyme immunoassay has tested blood sera from 136 patients with icteric acute hepatitis C (AHC) and 45 patients with chronic HCV infection for IgG antibodies to antigens of proteins core, NS4, NS5, HCV. Synthetic peptides core-16, NS4-20, NS5-23 were used as antigens. RESULTS: Patients with icteric AHC had IgG antibodies to antigens of both structural protein core and non-structural proteins NS4, NS5 of HCV as early as the first 10 days of jaundice. Occurrence of anti-core and anti-NS4 increases with the disease duration. Incidence of anti-NS4 correlated with duration of previous intravenous drug addiction. In patients with AHC early in the icteric period anti-core, anti-NS4, anti-NS5 were present less frequently than in patients with chronic HCV infection having elevated levels of AlAT. Significant differences were found neither with the group with normal AlAt nor in the spectrum of the detected antibodies between patients with acute and chronic HCV infection. CONCLUSION: Despite different frequency of anti-core, anti-NS4, anti-NS5 detection in patients with icteric AHC and patients with chronic HCV-infection and high AlAT, their high incidence rate in this or that group and absence of differences by the spectrum of the studied antibodies do not allow the fact of their detection to be a diagnostic marker differentiating acute HCV-infection with chronic one.

[Serological study of hepatitis C virus NS5 protein epitopes and their clinical and diagnostic significance]. / Serologicheskoe issledovanie épitopov belka NS5 virusa gepatita C i ikh znachenie dlia kliniki i diagnostiki.

Three peptides corresponding to the 2295-2317 aa NS5 HCV region and individual parts of this region were synthesized. Antigenic properties of these peptides were investigated. The 2295-2317 aa region contains at least two epitopes of different nature. The full-sized peptide is more promising for the diagnostic studies. Optimal conditions for ELISA with this peptide were defined, allowing the maximum complete utilization of the potentialities of both epitopes.

[Interaction of collagenases with certain peptide substrates and inhibitors]. / Vzaimodeistvie kollagenaz s nekotorymi peptidnymi substratami i ingibitorami.

Interactions of collagenases I and II (clostridiopeptidases) from Clostridium histolyticum with hexapeptide substrates in which some L-proline residues are replaced by their D-analogues, as well as with the tripeptide chloromethyl ketone Z-Gly-Pro-Gly-CH2Cl were studied. A role of stereochemistry of the amino acid residues in the substrate was established and differences between the collagenases, with regard to their specific requirements to substrates, were revealed. The tripeptide chloromethyl ketone is shown to be a specific collagenase inhibitor modifying at the substrate-binding site in the active centre of these enzymes, most likely lysine residues.

[Synthesis of acridine derivatives of amino acid hydrazines and their antimalarial activity]. / Sintez akridinovykh proizvodnykh gidrazidov aminokislot i ikh protivomaliariinaia aktivnost'.

2-Methoxy-6-chloroacridine-9-yl- and 2-ethoxy-6-nitroacridine-9-yl-hydrazides of glycine, alpha- and beta-alanines, gamma-aminobutiric acid, epsilon-aminocaproic acid have been synthesized and their antimalarial activity has been investigated. The compounds were found to inhibit the growth of malaria parasite P. falciparum in in vitro cultures. Fifty per cent inhibitory concentrations ranged from 2 x 10(-7) to 6 x 10(-7) M and corresponded to therapeutic concentrations of known quinoline and acridine antimalarial drugs. The beta-alanine and gamma-aminobutiric acid derivatives were the most active and showed high activity against a chloroquine resistant strain of P. falciparum.

[Synthesis of octapeptides containing fragments of lac-repressor primary structure]. / Sintez oktapeptidov, soderzhashchikh fragmenty pervichnoi struktury lac-repressora.

Four octapeptides containing the dipeptide fragments of the lac-repressor primary structure have been synthesized. The general scheme of synthesis consisted in the preparation of tetrapeptides using successive elongation from the C-terminus by the mixed anhydride method followed by their condensation into octapeptides.