DNAzyme-Catalyzed Site-Specific N-Acylation of DNA Oligonucleotide Nucleobases

We used in vitro selection to identify DNAzymes that acylate the exocyclic nucleobase amines of cytidine, guanosine, and adenosine in DNA oligonucleotides. The acyl donor was the 2,3,5,6-tetrafluorophenyl ester (TFPE) of a 5'-carboxyl oligonucleotide. Yields are as high as >95 % in 6 h. Several of the N-acylation DNAzymes are catalytically active with RNA rather than DNA oligonucleotide substrates, and eight of nine DNAzymes for modifying C are site-specific (>95 %) for one particular substrate nucleotide. These findings expand the catalytic ability of DNA to include site-specific N-acylation of oligonucleotide nucleobases. Future efforts will investigate the DNA and RNA substrate sequence generality of DNAzymes for oligonucleotide nucleobase N-acylation, toward a universal approach for site-specific oligonucleotide modification.

Novel heteroaryl replacements of aromatic 3-tetrafluoroethoxy substituents in trifluoro-3-(tertiaryamino)-2-propanols as potent inhibitors of cholesteryl ester transfer protein

A series of novel N,N-disubstituted trifluoro-3-amino-2-propanols has been prepared as potent inhibitors of cholesteryl ester transfer protein (CETP). Modifying the aromatic 3-tetrafluoroethoxy group in the lead molecule 1a with various heteroaryl moieties produced new 2-furyl analogues 2a,b with submicromolar potency in vitro.

Butenolide endothelin antagonists with improved aqueous solubility

Continued development around our ETA-selective endothelin (ET) antagonist 1 (CI-1020) has led to the synthesis of analogues with improved aqueous solubility profiles. Poor solubility characteristics displayed by 1 required a complex buffered formulation in order to conduct iv studies. To overcome the use of specific iv formulations for preclinical studies on additional drug candidates, analogues with improved aqueous solubility were desired. Several analogues were synthesized with substitution patterns that allowed for the formation of either acid or base addition salts. These derivatives had dramatically improved aqueous solubility. In addition, these analogues retained equivalent or improved ETA receptor selectivity and antagonist potency, versus 1, both in vitro and in vivo. Compound 29, which contains as a substituent the sodium salt of a sulfonic acid, has an ETA IC50 = 0.38 nM, ETA selectivity of 4200-fold, and ETA functional activity of KB = 7.8, all of which are similar or superior to those of 1. Compound 29 also has vastly superior aqueous solubility and solubility duration, compared to 1. Furthermore, 29 after iv infusion displays improved activity to 1 in preventing acute hypoxia-induced pulmonary hypertension in rats with an ED50 = 0.3 microg/kg/h.

Synthesis of novel substituted pyridines as inhibitors of endothelin converting enzyme-1 (ECE-1)

A series of bi-aryl pyridine carboxylic acids has been prepared and evaluated as inhibitors of ECE-1. The analogs were prepared by Pd catalyzed cross couplings of halogenated pyridines with heteroaryl organo-boranes, -tinate or -zincate derivatives.

Hepatitis B and C virus sexual transmission among homosexual men

OBJECTIVE

We estimated hepatitis B virus (HBV) and hepatitis C virus (HCV) sexual transmission among homosexual men.

METHODS

Two hundred twenty-eight homosexually active men attending two clinical centers and presenting no risk factors except for sexual exposure were interviewed, and a blood sample was drawn. HBV marker test was performed using enzyme-linked immunosorbent assay (ELISA) and radioimmunoassay, and HCV was tested using ELISA-2 and recombinant immunoblot assay-2.

RESULTS

HBV and HCV infection prevalence rates were 34.4% and 12.7%, respectively. Using logistic regression analysis including sexual exposure and controlling for confounders, we found that anal receptive intercourse (odds ratio [OR] = 4.01; 95% confidence interval [CI] = 1.34-11.94), duration of homosexuality (OR = 3.43; 95% CI = 1.29-9.12), insertive anilingus (OR = 2.02; 95% CI = 1.06-3.87), and sexually transmitted diseases (OR = 1.87; 95% CI = 1.00-3.47) were independently associated with the risk of HBV sexual transmission. We did not find any association between sexual behavior and HCV transmission.

CONCLUSIONS

Sexual behavior is a plausible explanatory factor of HBV sexual transmission among homosexual men. Further evidence is needed to elucidate the occurrence and the efficiency of HCV sexual transmission in the absence of other risk factors.