Azetidines and spiro azetidines as novel P2 units in hepatitis C virus NS3 protease inhibitors

Herein, we report the synthesis and structure–activity relationship studies of new analogs of boceprevir 1 and telaprevir 2. Introduction of azetidine and spiroazetidines as a P2 substituent that replaced the pyrrolidine moiety of 1 and 2 led to the discovery of a potent hepatitis C protease inhibitor 37c (EC₅₀ = 0.8 μM).     

Synthesis and evaluation of Janus type nucleosides as potential HCV NS5B polymerase inhibitors

The synthesis of new ribo and 2′-β-C-methyl ribo Janus type nucleosides J-AA, J-AG and J-AU is reported along with their ability to block HCV and HIV replication. Their toxicity was also assessed in Huh7, human lymphocytes, CEM and Vero cells.     

Adventitial ablation technique that permits the assessment of adventitial-dependent contribution to microvascular contractile function

Resistance arteries have been implicated as a major contributing factor in the sequela of disease conditions such as hypertension and diabetes and, as such, are a major focus of cardiovascular research. The paracrine influence of the intimal endothelial layer of resistance arteries is well established. Considering the growing body of evidence substantiating a functionally relevant vascular adventitia, in this study we have established a technique that permits determination of the functional influence of the adventitial layer on resistance artery tone. Isolating adventitial-dependent function, analogous to isolating endothelial function, has potentially significant implications for studying the as yet unexplored role of the microvascular adventitial layer in modulating acute vascular contractile function.     

Effect of environmental factors on the kinetics of insulin fibril formation: elucidation of the molecular mechanism

In the search for the molecular mechanism of insulin fibrillation, the kinetics of insulin fibril formation were studied under different conditions using the fluorescent dye thioflavin T (ThT). The effect of insulin concentration, agitation, pH, ionic strength, anions, seeding, and addition of 1-anilinonaphthalene-8-sulfonic acid (ANS), urea, TMAO, sucrose, and ThT on the kinetics of fibrillation was investigated. The kinetics of the fibrillation process could be described by the lag time for formation of stable nuclei (nucleation) and the apparent rate constant for the growth of fibrils (elongation). The addition of seeds eliminated the lag phase. An increase in insulin concentration resulted in shorter lag times and faster growth of fibrils. Shorter lag times and faster growth of fibrils were seen at acidic pH versus neutral pH, whereas an increase in ionic strength resulted in shorter lag times and slower growth of fibrils. There was no clear correlation between the rate of fibril elongation and ionic strength. Agitation during fibril formation attenuated the effects of insulin concentration and ionic strength on both lag times and fibril growth. The addition of ANS increased the lag time and decreased the apparent growth rate for insulin fibril formation. The ANS-induced inhibition appears to reflect the formation of amorphous aggregates. The denaturant, urea, decreased the lag time, whereas the stabilizers, trimethylamine N-oxide dihydrate (TMAO) and sucrose, increased the lag times. The results indicated that both nucleation and fibril growth were controlled by hydrophobic and electrostatic interactions. A kinetic model, involving the association of monomeric partially folded intermediates, whose concentration is stimulated by the air-water interface, leading to formation of the critical nucleus and thence fibrils, is proposed.     

T-DNA recombination and replication in maize cells

T-DNA recombination and replication was analyzed in 'black mexican sweet' (BMS) cells transformed with T-DNAs containing the replication system from wheat dwarf virus (WDV). Upon recombination between the T-DNA ends, a promoterless marker gene (gusA) was activated. Activation of the recombination marker gene was delayed and increased exponentially over time, suggesting that recombination and amplification of the T-DNA occurred in maize cells. Mutant versions of the viral initiator gene (rep), known to be defective in the replication function, failed to generate recoverable recombinant T-DNA molecules. Circularization of T-DNA by the FLP/FRT site-specific recombination system and/or homologous recombination was not necessary to recover circular T-DNAs. However, replicating T-DNAs appeared to be suitable substrates for site-specific and homologous recombination. Among 33 T-DNA border junctions sequenced, only one pair of identical junction sites was found implying that the population of circular T-DNAs was highly heterogenous. Since no circular T-DNA molecules were detected in treatments without rep, it suggested that T-DNA recombination was linked to replication and might have been stimulated by this process. The border junctions observed in recombinant T-DNA molecules were indicative of illegitimate recombination and were similar to left-border recombination of T-DNA into the genome after Agro-mediated plant transformation. However, recombination between T-DNA molecules differed from T-DNA/genomic DNA junction sites in that few intact right borders were observed. The replicating T-DNA molecules did not enhance genomic random integration of T-DNA in the experimental configuration used for this study.     

A web server to locate periodicities in a sequence

Summary : FT is a tool written in C++, which implements the Fourier analysis method to locate periodicities in aminoacid or DNA sequences. It is provided for free public use on a WWW server with a Java interface. Availability : The server address is http://o2.db. uoa.gr/FT Contact : shamodr@atlas.uoa.gr      

Global transcriptional response of pig brain and lung to natural infection by Pseudorabies virus

Background  

Pseudorabies virus (PRV) is an alphaherpesviruses whose native host is pig. PRV infection mainly causes signs of central nervous system disorder in young pigs, and respiratory system diseases in the adult.     

“Unblocking” Serum Activity <Emphasis Type="Italic">in vitro</Emphasis> in the Polyoma System may Correlate with Antitumour Effects of Antiserum <Emphasis Type="Italic">in vivo</Emphasis>

In a variety of tumour systems, individuals carrying progressively growing neoplasms have lymphoid cells with a specific cytotoxic effect on cultured tumour cells from the same individual^1–4. Since the sera of tumour-bearing individuals have been shown to prevent tumour cell destruction by immune lymphocytes in vitro^2,5–8 and since this serum blocking activity appears early in primary and transplant tumour development^5,7, it has been suggested that the appearance of this serum blocking activity might be responsible for the progressive growth of tumours in individuals having cytotoxic lymphocytes. Counteraction of this blocking activity would thus be of primary importance in facilitating the function of an already existing or bolstered cell-mediated immunity. The serum blocking activity might be inhibited in various ways, by preventing the formation of blocking antibody or by interfering with its action (“unblocking”), as demonstrated in Moloney sarcoma regressor sera⁹. This type of serum also has a therapeutic effect on Moloney sarcomas in vivo^10,11, which has been tentatively attributed to its unblocking activity^8,9 or, possibly, to a complement-dependent cytotoxicity¹⁰. Tumour growth in the Moloney sarcoma system, however, might be due in part to continuous recruitment of neoplastic cells by virus-induced transformation and so the therapeutic effect could be due to a virus-neutralizing serum activity^9,10.