The nucleotide phosphonates cidofovir (CDV) and cyclic cidofovir (cCDV) are potent antiviral compounds when administered parenterally but are not well absorbed orally. These compounds have been reported to have activity against orthopoxvirus replication in vitro and in animal models when administered parenterally or by aerosol. To obtain better oral activity, we synthesized a novel series of analogs of CDV and cCDV by esterification with two long-chain alkoxyalkanols, 3-hexadecyloxy-1-propanol (HDP-CDV; HDP-cCDV) or 3-octadecyloxy-1-ethanol (ODE-CDV; ODE-cCDV). Their activities were evaluated and compared with those of CDV and cCDV in human foreskin fibroblast (HFF) cells infected with vaccinia virus (VV) or cowpox virus (CV) using a plaque reduction assay. The 50% effective concentrations (EC 50 s) against VV in HFF cells for CDV and cCDV were 46.2 and 50.6 M compared with 0.84 and 3.8 M for HDP-CDV and HDP-cCDV, respectively. The EC 50 s for ODE-CDV and ODE-cCDV were 0.20 and 1.1 M, respectively. The HDP analogs were 57-and 13-fold more active than the parent nucleotides, whereas the ODE analogs were 231-and 46-fold more active than the unmodified CDV and cCDV. Similar results were obtained using CV. Cytotoxicity studies indicated that although the analogs were more toxic than the parent nucleotides, the selective index was increased by 4-to 13-fold. These results indicate that the alkoxyalkyl esters of CDV and cCDV have enhanced activity in vitro and need to be evaluated for their oral absorption and efficacy in animal models.Since smallpox was considered to be eradicated in the 1970s, there has been little activity in developing antiviral agents for this infection (10). However, in view of the threat of bioterrorism using variola virus or other orthopoxviruses, such as monkeypox virus, which continues to infect humans in central Africa, there is a renewed need to develop antiviral agents for these viruses (3,11,12,17,18,24). For many years the laboratory of Erik De Clercq and other laboratories have utilized in vitro and animal models with vaccinia virus (VV) to screen potential antiviral compounds for activity against poxviruses and have identified a few active agents. Methisazone, ribavirin, idoxuridine, interferon, interferon inducers, S2442, and cidofovir (CDV) have been identified as potential therapies for these infections (7,8,9,20,21,23). Of particular interest was the finding that CDV and other phosphonate nucleotides were inhibitory to this group of viruses, including VV, cowpox virus (CV), camelpox virus, monkeypox virus, and variola virus (J. W. Huggins, personal communication). The activity of CDV is of particular interest as a potential therapy for smallpox, as it is already approved for the treatment of cytomegalovirus (CMV) infections and has been shown to have activity in animal models using VV and CV (2,22,26,27). We have confirmed the activity of CDV against both VV and CV in tissue culture and animal models in our laboratory (4) and report here the results of some new alkoxyalkyl esters o...

The incidence of cytomegalovirus (CMV) retinitis is declining in AIDS patients but remains a significant clinical problem in patients with organ transplants and bone marrow transplants. Prophylaxis with ganciclovir (GCV) or valganciclovir reduces the incidence of CMV disease but may lead to the emergence of drug-resistant virus with mutations in the UL97 or UL54 gene. It would be useful to have other types of oral therapy for CMV disease. We synthesized hexadecyloxypropyl and octadecyloxyethyl derivatives of cyclic cidofovir (cCDV) and cidofovir (CDV) and found that these novel analogs had 2.5-to 4-log increases in antiviral activity against CMV compared to the activities of unmodified CDV and cCDV. Multiple-log increases in activity were noted against laboratory CMV strains and various CMV clinical isolates including GCV-resistant strains with mutations in the UL97 and UL54 genes. Preliminary cell studies suggest that the increase in antiviral activity may be partially explained by a much greater cell penetration of the novel analogs. 1-O-Hexadecyloxypropyl-CDV, 1-O-octadecyloxyethyl-CDV, and their corresponding cCDV analogs are worthy of further preclinical evaluation for treatment and prevention of CMV and herpes simplex virus infections in humans.Although the incidence and prevalence of cytomegalovirus (CMV) retinitis in AIDS patients are declining due to the use of highly active antiretroviral therapies (12), CMV continues to be a major cause of opportunistic infections in patients with allogeneic bone marrow transplants (BMTs) and solid-organ transplants (6). In transplant patients, the incidence of CMV infection increases with the duration and degree of immunosuppression, approximating 70% in allogeneic BMT patients who are CMV seropositive (2) and in patients receiving solidorgan transplants from CMV-seropositive donors (4, 18). CMV disease is associated with a high risk of morbidity and mortality in solid-organ transplant and allogeneic BMT patients (6). While prophylaxis with ganciclovir (GCV) significantly reduces the incidence of CMV disease in transplant recipients, drug resistance may emerge because of mutations in the UL97 gene, which catalyzes the initial phosphorylation of GCV, or in the UL54 polymerase gene of the virus (for a review, see reference 5). Current therapies for CMV disease in transplant patients are based primarily on intravenous therapy with GCV, cidofovir (CDV), or foscarnet (phosphonoformate) or, more recently, with oral valganciclovir.It would be useful to identify more effective oral therapies for the treatment of CMV disease in allogeneic bone marrow, stem cell, or solid-organ transplant patients and in CMV retinitis patients with AIDS. We have developed a strategy to improve the antiviral activity and oral absorption of acyclovir (ACV) and GCV by covalently attaching alkoxyalkyl or alkoxyglyceryl residues to the phosphate of ACV monophosphate or GCV monophosphate (1,8,9). These ether lipid analogs generally show severalfold increases in activity over the activity of underiva...

In response to stressful stimuli, animals activate the hypothalamic-pituitary-adrenal axis, which can result in transition to the "emergency life history stage." A key adaptive characteristic of this life history stage is the mobilization of energy stores. However, few data are available on the metabolic response to acute stress in wild-caught, free-ranging birds. We quantified the effect of acute capture and restraint stress on plasma glucose, free fatty acid, and uric acid in free-ranging Abert's towhees Melozone aberti. Furthermore, birds were caught from urban and desert localities of Phoenix, Arizona, to investigate potential effects of urban versus desert habitats on the corticosterone (CORT) and metabolic response to acute stress. Complementing work on free-ranging birds, captive towhees received CORT-filled Silastic capsules to investigate the response of urban and desert conspecifics to long-term CORT administration. We quantified the effect of CORT administration on baseline plasma glucose and uric acid, liver and pectoralis muscle glycogen stores, kidney phosphoenolpyruvate carboxykinase (PEPCK-C, a key gluconeogenic enzyme), and body mass. Acute stress increased plasma CORT and glucose and decreased plasma uric acid but had no effect on plasma free fatty acid. There was no difference between urban and desert localities in body mass, fat scores, and the response to acute stress. CORT administration decreased body mass but had no effect on glucose and uric acid, pectoral muscle glycogen, or kidney PEPCK-C. However, liver glycogen of CORT-treated urban birds increased compared with corresponding controls, whereas glycogen decreased in CORT-treated desert birds. This study suggests that Abert's towhees principally mobilize glucose during acute stress but urban and desert towhees do not differ in their CORT and metabolic response to acute stress or long-term CORT administration.

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The regulatory networks governing morphogenesis of a pleomorphic fungus, Candida albicans are extremely complex and remain to be completely elucidated. This study investigated the function of C. albicans yeast casein kinase 2 (CaYck2p). The yck2Δ/yck2Δ strain displayed constitutive pseudohyphae in both yeast and hyphal growth conditions, and formed enhanced biofilm under non-biofilm inducing condition. This finding was further supported by gene expression analysis of the yck2Δ/yck2Δ strain which showed significant upregulation of UME6, a key transcriptional regulator of hyphal transition and biofilm formation, and cell wall protein genes ALS3, HWP1, and SUN41, all of which are associated with morphogenesis and biofilm architecture. The yck2Δ/yck2Δ strain was hypersensitive to cell wall damaging agents and had increased compensatory chitin deposition in the cell wall accompanied by an upregulation of the expression of the chitin synthase genes, CHS2, CHS3, and CHS8. Absence of CaYck2p also affected fungal-host interaction; the yck2Δ/yck2Δ strain had significantly reduced ability to damage host cells. However, the yck2Δ/yck2Δ strain had wild-type susceptibility to cyclosporine and FK506, suggesting that CaYck2p functions independently from the Ca+/calcineurin pathway. Thus, in C. albicans, Yck2p is a multifunctional kinase that governs morphogenesis, biofilm formation, cell wall integrity, and host cell interactions.