Novel anti-RSV dianionic dendrimer-like compounds: design, synthesis and biological evaluation.

Human Respiratory Syncytial Virus (RSV) is considered to be the leading cause of lower respiratory tract disease in infants and young children. RSV is also a common pathogen in immunocompromised adults and in the elderly. RSV infection can be epidemic and is evident worldwide. Ribavirin, a small molecule agent, and Synagis, a monoclonal neutralizing antibody, are the only approved drugs for treatment and prevention of RSV in high-risk patients. This review is focused on a group of novel and specific inhibitors discovered at Wyeth-Ayerst Research. Some of these inhibitors have IC50 <50 nM and are active against all the tested group A and B viruses. They also have shown good efficacy in cotton rats and primates. Mechanism of action studies indicate that the compounds inhibit the next step in infection after adsorption suggesting that fusion is the target. A strong relationship between the inhibitor structures and their anti-RSV activity was established. This relationship appears to derive from a multivalent interaction between the functional groupings of the inhibitors and the F protein, which seem to be highly complementary and directional.

CL387626 exhibits marked and unusual antiviral activity against respiratory syncytial virus in tissue culture and in cotton rats.

CL387626 (4,4'-Bis[4,6-di[3-aminophenyl-N,N-bis(2-carbamoylethyl)-sulfon ilimino]-1,3,5-triazine-2-ylamino-bi-phenyl-2,2'-disulfonic acid, disodium salt), a compound synthesized by Wyeth-Ayerst Research Laboratories, was tested for its cytotoxicity and antiviral activity against respiratory syncytial virus (RSV) in tissue culture and in cotton rats. The median cell inhibitory (IC50) and median efficacious (EC50) concentrations of CL387626 against RSV in proliferating HEp2 or Vero tissue culture cells were determined to be 375 and 0.25 microg/ml, respectively, giving the compound an apparent selective index (S.I.) of 1500. This compound also exhibited uncommon antiviral activity against RSV in cotton rats. In multiple experiments, a single 30 mg/kg dose of CL387626 administered intranasally 4 or 5 days prior to virus challenge, significantly inhibited pulmonary replication of RSV compared to that seen in control animals inoculated similarly with placebo (i.e. water). In contrast to these results, most lots of CL387626 failed to significantly inhibit pulmonary RSV replication when administered utilizing therapeutic administration schedules. Although some cytotoxicity was noted in tissue culture assays, no overt toxic effects were noted in any test animal, including those inoculated with > 300 mg CL387626/kg, a dose approximately 150 times the apparent minimal efficacious dose (i.e. 1.9 mg/kg).

Isolation of individual amino acids from various microbiological sources using reversed-phase high-performance liquid chromatography.

A new method for the preparative isolation of individual amino acids on a milligram scale based on reversed-phase high-performance liquid chromatography (RP-HPLC) after pre-column derivatization with carbobenzoxychloride (Z-Cl) has been developed. The chromatographic procedure was tested by the investigation of jack bean urease hydrolysate. The method has been applied to the preparative separation of Z-amino acids (from 10 up to 16) obtained from protein hydrolysates of various sources (green microalgae, blue-green algae, halophilic and methylotrophic microorganisms) and was proved to be reliable by the separation of deuterated amino acids (enrichment 97-99%) from Methylobacillus flagellatum (due to the bioconversion of CD3OD and D2O). Independent of the biological source of the protein, the amino acids were isolated with high recovery (from 68% up to 89%) and chromatographic purity (from 96% up to 99%). The method was also applied for the isolation of phenylalanine and leucine excreted by amino-acid overproducing microorganisms.

[Synthesis of nucleoside analogs containing a cis-2-pentene fragment and their triphosphates]. / Sintez analogov nukleozidov, soderzhashchikh tsis-2-pentenovyi fragment, i ikh trifosfatov.

Acyclic analogs of thymidine, adenine, and cytosine where the ribose moiety is replaced with cis-5-hydroxypenthene, were obtained via condensation of cis-5-acetoxy-1-bromo-2-pentene with nucleic acid bases. Triphosphate derivatives of the new nucleosides were also synthesized to evaluate their action as terminators of DNA synthesis catalyzed by DNA polymerases.

1-O-benzyl-2-O-methyl-rac-glycerol: a key intermediate for synthesis of ether glycerolipids.

A new scheme for synthesis of saturated 1-O-alkyl-2-O-methyl-rac-glycerolipids is described. The reductive cleavage of 2-O-methyl-1,3-O,O-benzylideneglycerol with BH3.THF complex leads to 1-O-benzyl-2-O-methyl-rac-glycerol, which is a key in intermediate for the facile preparation of 1-O-alkyl-2-O-methyl-rac-glycerol and derivatives.

Acyclic analogs of dideoxydidehydronucleosides.

A new type of acyclic nucleoside analogs is proposed, containing C5 hydroxyalkyl fragments, where the distance between 5'-hydroxyl group and the heterocyclic moiety corresponds to that in dideoxydidehydronucleosides (as confirmed by computer modelling). Condensation between 5-0-acetyl-1-bromo-2-pentene and persilylated heterocyclic bases (pyrimidines and guanine) or adenine sodium salt gives rise to the acyclic nucleosides (5a-d, 6a-d) with the yields ranging from 40% up to 85%. Deprotection by NH3/MeOH results in the desired nucleosides (1a-d, 2a-d) formation.

C(13)-substituted bacteriorhodopsin analogs.

13-Ethyl-, 13-isopropyl-, 13-tert-butyl-, 13-phenyl-, 13-alpha-naphthyl-, and 13-demethyl-retinals were synthesized and incubated with bacterioopsin (bO) to give the corresponding bacteriorhodopsin (bR) analogs. The capability of the 13-tert-butyl- and 13-alpha-naphthyl-bRs to exist and to photocycle shows that apparently around C(13) of the chromophore there lies a large enough cavity. A study of the light-induced conversions of the artificial pigments prepared has shown that the introduction at position 13 of the chromophore of the hydrocarbon substituents bulkier than that of the natural bR diminished the amplitudes of the electric photoresponses. Bulky C(13)-substituents or absence of substitution at that position decelerated the relaxation of the M-intermediates and disturbed the 13-cis-in equilibrium all-trans-isomerization.

An investigation of the electrochemical cycle of bacteriorhodopsin analogs with the modified ring.

5,6-Epoxy-, 4-methoxy-, 4-hydroxy-, and 3,4-dehydrobacteriorhodopsins can generate delta psi coupled to a photochemical cycle with intermediate M. The kinetics of delta psi comprises three main electrogenic phases: the fast small negative, the microsecond, and the millisecond positive phases. The photocycle efficiency is lower in all the analogs. The photocycle is modified insignificantly only in 3,4-dehydrobacteriorhodopsin. In the other pigments the decay of the flash-induced bleaching in the chromophore main absorption band is slower than the decay of M or long-wave intermediates, especially in the 4-hydroxy analog. In the latter analog, such distinctions, according to delta pH measurements, are partly due to deceleration of the decay of the novel intermediate (P). In 5,6-epoxybacteriorhodopsin, at all wavelengths, the decay of the intermediates takes seconds upon M formation. According to our and literature data, no bacteriorhodopsin analogs are known to have a cycle which preserves the M-intermediate and does not transport a proton.

[Synthesis and properties of C13-substituted retinals]. / Sintez i svoistva C13-zameshchennykh retinalei.

Several analogues of all-trans-retinal were synthesised, containing, instead of CH3-group at C13, the following substituents: H, C[2H]3, C2H5, iso-C3H7, C4H9, C6H5 or alpha-C10H8. The compounds synthesised on coupling with bacterioopsin gave artificial chromoproteins, which retained the ability to participate in the cycle of photochemical transformations and H+-transport.

[Retinol receptors in rat retina: various molecular forms]. / Retseptisia retinola v setchatke krys: razlichnye molekuliarnye formy.

Analysis of vitamin A-binding components in a soluble fraction of rat retina was carried out using gel filtration and gradient ultracentrifugation. Use of a wide range of concentrations of labelled retinol (6.10-8 = 2. 10-5 M) enabled to detect both high and low molecular forms of the binding components of retina. High molecular components (5S, 7S) were mainly found at physiological concentrations of retinol and at the higher (10-6=10-5 M) concentrations. Low molecular mass receptor (2S) prevailed under conditions of loading of the soluble fraction with subphysiological (nmol) concentrations of retinol.

[Some features of rhodopsin regeneration process in the presence of exogenous 11Z-retinal in teleosts]. / O nekotorykh osobennostiakh pritsessa Regeneratsii podopsina morskikh kostistykh ryb v prisutstvii ekzogennogo 11Z-retinalia.

The rate of rhodopsin regeneration in decolorized rod outer segments ROS of pollock and ruff in the presence of exogenous 11Z-retinal is found to depend slightly on the temperature. The Arrhenius curve is linear within 0--20 degrees C and 0--30 degrees C in case of pollock and black ruff ROS respectively. The increase of the regeneration temperature above the upper limit results in both cases in the decrease of the chromophore binding rate due to the temperature denaturation of fish opsin. The rate of opsin regeneration in bovine ROS is temperature-dependent within 0--50 degrees C, the Arrhenius curves having a specific break with the temperature conversion at 12--13 degrees, which indicates a different 11Z-retinal binding rate with bovine opsin at low and high temperatures. Maximal rhodopsin regeneration temperature was observed within 5--10 min. for fish ROS and 1.5 hour for bovine ROS. Trimethylcyclohexene derivatives with a side chain of about 7 carbon atoms and 13Z-retinal competitively inhibited the rhodopsin regeneration in pollock and bovine ROS, while 13E-11, 12-dehydroretinal and all-E-retinal did not effect this process. Some peculiarities of the rhodopsin regeneration process in fish are discussed in connection with the molecular organization of a lipid phase of photoreceptor membrane and chromophore-binding region.