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Biomedical subjects

W H Prusoff

Publications and source records attributed to W H Prusoff.

At least 73 records · Page 4Linked to original sources
PubMed1980

The incorporation of 5-iodo-5'-amino-2',5-dideoxyuridine and 5-iodo-2'-deoxyuridine into herpes simplex virus DNA. Relationship between antiviral activity and effects on DNA structure.

Isopycnic centrifugation in CsCl gradients was used to quantify the incorporation of 5-iodo-5'-amino-2',5'-dideoxyuridine and 5-iodo-2'-deoxyuridine into herpes simplex virus type 1 DNA. A parallelism between the degree of incorporation into viral DNA and the inhibition of herpes simplex virus type I replication was found for both thymidine analogs. A concentration of 5-iodo-5'-amino-2',5'-dideoxyuridine approximately 100 times greater than 5-iodo-2'-deoxyuridine was required to achieve similar levels of antiviral activity. However, the inhibitory effects of these compounds are similar when compared with respect to the percent of substitution for thymidine in herpes simplex virus type I DNA. Damage to the viral DNA, as indicated by the presence of single or double-stranded breaks, was assessed by centrifugation in alkaline and neutral sucrose gradients. The incorporation of 5-iodo-5'-amino-2',5'-dideoxyuridine into herpes simplex virus type I DNA produced single and, to a lesser extent, double-stranded breaks in a dose-dependent manner. 5-Iodo-2'-deoxyuridine did not, however, induced DNA breakage. These data indicate that the additional presence of a phosphoramidate bond in the DNA produced the extensive damage detected under these conditions, but that such damage is not required for antiviral activity.

Antiviral Agents↗
PubMed1980

Synthesis and biological activities of 5-(hydroxymethyl, azidomethyl, or aminomethyl)-2'-deoxyuridine and related 5'-substituted analogues.

The synthesis of 5-(azidomethyl)-2'-deoxyuridine (10) has been accomplished by two independent methods. The first involved tosylation of 5-(hydroxymethyl)-2'-deoxyuridine (1) to furnish a mixture of two mono- and a ditosyl nucleosides which were converted into the corresponding 5-(azidomethyl) (10), 5-(azidomethyl)-5'-azido (14), and 5-(hydroxymethyl)-5'-azido (15) derivatives of 2'-deoxyuridine. The second method was more selective and required the formation of the intermediate 5-(bromomethyl)-3',5'-di-O-acetyl-2'-deoxyuridine (8), followed by displacement of the bromo group by lithium azide and deacetylation. Catalytic hydrogenation of the azides 9, 10, 14, and 15 gave the corresponding amines 16, 2, 6, and 7, respectively. Compounds 1, 2, 10, and 16 inhibited the growth of murine Sarcoma 180 and L1210 in culture, and the activity of 2 was prevented by 2'-deoxypyrimidine nucleosides but not by purine nucleosides. The replication of herpes simplex virus type 1 (HSV-1) was strongly inhibited only by 1 and 10. Studies on the binding of the various thymidine analogues to HSV-1 encoded pyrimidine deoxyribonucleoside kinase indicate that 1 and 10 have good affinity for the enzyme.

Animals↗
PubMed1980

Synthesis and antineoplastic activity of a novel series of phosphoramide mustard analogues of pyrimidine deoxyribonucleosides.

A novel series of cyclophosphamide derivatives of pyrimidine deoxyribonucleosides (6-9) has been synthesized from the corresponding amino nucleosides. Our preliminary findings have shown that three of these cyclophosphamide nucleoside analogues, 6, 7, and 9, have potent inhibitory effects on the replication of L1210 cells in vitro (ED50 = 1.2-1.5 x 10(-5) M). Since cyclophosphamide (cytoxan) has no cytotoxicity under these conditions, our findings indicate that these novel phosphamide derivatives have unusual biological properties which may include a unique mode of activation.

Animals↗
PubMed1980

Synthesis and biological activities of chloroethylurea, methylurea, and nitrosourea analogues of N-deacetylmethylthiocolchicine.

A series of urea and nitrosourea analogues of N-deacetylmethylthiocolchicine (1) has been synthesized, and their antineoplastic and antiviral activities were evaluated. The objective for combination of two active moieties, such as thiocolchicine and nitrosourea, into one molecule was the generation of compounds with potential improved biological and pharmacological properties. The ED50 for 2, 3, 4, and 5 was 1.6, 1.2, 3.3, and 1.8 X 10(-8) M for L1210 cells and 3.0, 2.7, 2.9, and 2.6 X 10(-8) M for S-180 cells, respectively. The synthesis and cytotoxic and antiviral properties of these compounds are discussed.

Animals↗
PubMed1980

Topical therapeutic efficacy of 9-(2-hydroxyethoxymethyl)guanine and 5-iodo-5'-amino-2',5'-dideoxyuridine on oral infection with herpes simplex virus in mice.

The therapeutic efficacy of two new antiviral agents, 5-iodo-5'-amino-2', 5'-dideoxyuridine (AIdUrd) and 9-(2-hydroxyethoxymethyl)guanine (ACV), in the model of mouse lip inoculated with herpes simplex virus type 2 is reported. The effects on development of clinical lesions, viral replication in the inoculated lips, and establishment of latent viral infection in the trigeminal ganglia were observed. The earlier the treatment with AIdUrd and ACV was initiated after inoculation, the better was the chemotherapeutic effect. AIdUrd and ACV treatment, when initiated 48 and 72 hr after inoculation, respectively, showed no chemotherapeutic efficacy. Establishment of viral latent infection in sensory ganglia was significantly prevented only when ACV treatment was initiated very early (1 or 3 hr) after inoculation. The results indicate that both drugs have significant antiviral activity, in part dependent on the time of initiation of therapy, and that ACV is superior to AIdUrd as a topical agent for therapy of herpes simplex virus type 2 infections.

Acyclovir↗
PubMed1980

5'-Amino-5'-deoxythymidine: synthesis, specific phosphorylation by herpesvirus thymidine kinase, and stability to pH of the enzymically formed diphosphate derivative.

Radioactive 5'-amino-5'-deoxythymidine (5'-AdThd), an inhibitor of herpes simplex virus, was synthesized by direct amination of monotosylated thymidine with concentrated ammonium hydroxide. Incubation of 5'-AdThd with purified herpes simplex virus type 1-encoded pyrimidine deoxyribonucleoside kinase produced the diphosphate derivative. The monphosphate derivative of 5'-AdThd was not detected as a reaction product of this enzymatic phosphorylation. A purified mixture of nonviral thymidine kinase and thymidylate kinase derived from uninfected Vero cells was unable to phosphorylate 5'-AdThd under identical conditions. The rate of hydrolysis of 5'-AdThd diphosphate increased as the pH of the reaction mixture decreased, with a shoulder region appearing between pH 3 and 5. The rate of hydrolysis was markedly increased below pH 3. 5'-AdThd, but not the monophosphate derivative, was detected in the hydrolysis mixture. The hydrolysis of 5'-AdThd diphosphate pH 3 also yielded some thymine in addition to 5'-AdThd.

Dideoxynucleosides↗
PubMed1980

Comparative analysis of the immunosuppressive properties of two antiviral, iodinated thymidine analogs, 5-iodo-2'-deoxyuridine and 5-iodo-5'-amino-2',5'-dideoxyuridine.

5-Iodo-5'-amino-2',5'-dideoxyuridine (AldUrd), given as five single i.p. injections on Days 0 to 4 after antigenic challenge with sheep erythrocytes, had no demonstrable effect on serum hemagglutinin titers in doses as high as 2000 mg/kg/day. This was the maximum feasible single dose, but no 10% lethal dose was determinable. Similarly, 5-iodo-2'-deoxyuridine (IdUrd), 50 mg/kg/day (10% lethal dose), on Days 0 to 4 did not significantly affect this humoral response. However, with a more sensitive assay, immunocytoadherence, reductions in the number of hemagglutinin-forming cells in the spleen were found at several levels of AldUrd and IdUrd, but the same level of inhibition was attained by a course of AldUrd, 2000 mg/kg, or IdUrd, 50 mg/kg. Spleen cell-mediated immunity against lethally irradiated L1210 was measured by 4-hr 51Cr release and 48-hr growth inhibition assays. Both drugs showed dose-related immunosuppression. With AldUrd, 2000 mg/kg/day, and IdUrd, 100 mg/kg/day, on Days 0 to 4, cytotoxicity was inhibited by 35 to 68% and 73 to 90%, respectively. In comparison, a similar course of 1-beta-D arabinofuranosylcytosine, 40 mg/kg/day, completely abrogated both humoral and cell-mediated immunity. When AldUrd and IdUrd were administered on Days -5 to -1, little effect on either type of immunity was found, while pretreatment with the alkylating agent, cyclophosphamide, abolished all T-cell-mediated killing as measured on Day 7. Thus, AldUrd appears to be a very mild and IdUrd a moderate to strong cell cycle-dependent immunosuppressive.

Animals↗
PubMed1979

Phosphorylation of 5-iodo-5'-amino-2',5',dideoxyuridine by herpes simplex virus type 1 encoded thymidine kinase.

Herpes simplex virus type 1 (HSV-1) encoded thymidine kinase converts 5-iodo-5'-amino-2',5'-dideoxyuridine (AIdUrd), a highly specific anti-herpes agent, into the 5'-diphosphate (AIdUDP) derivative in vitro. AIdUDP was identified by its acid lability, sensitivity to alkaline phosphatase hydrolysis, chromatographic behavior, and ratio of double isotope (125I, 32P) labeling. ATP, but not AMP, is a phosphate donor, and the direct transfer of the beta and gamma phosphate of ATP as pyrophosphate to AIdUrd was ruled out. The presence of a phosphoramidate bond was supported by the acid lability of AIdUDP which has a half life (t1/2) of 320 min at pH 3.0. At neutral pH, the hydrolysis products are AIdUrd and orthophosphate, with AIdUrd monophosphate being the probable hydrolytic intermediate at these pH values. However, at acidic pH, some pyrophosphate was detected in addition to AIdUrd and orthophosphate. AIdUrd competitively inhibited the phosphorylation of thymidine and deoxycytidine. Escherichia coli thymidine kinase, even though 100-fold higher in activity, was unable to phosphorylate AId-Urd under similar incubation conditions.

Chromatography, High Pressure Liquid↗
PubMed1979

Effect of 5-iodo-5'-amino-2',5'-dideoxyuridine on varicella-zoster virus in vitro.

The antiviral effect of the nucleoside analog 5-iodo-5'-amino-2',5'-dideoxyuridine (AIU) was tested with three isolates of varicella-zoster virus (VZV). AIU concentrations of 10 to 800 muM (3.5 to 288 mug/ml) reduced the number of plaques produced by VZV-infected cells and cell-free VZV from approximately 30 to 95%. Smaller plaque size was also observed in the presence of AIU. AIU was less effective than arabinofuranosylthymine in reducing VZV-induced plaques since as little as 5 mug of arabinofuranosylthymine per ml completely blocked plaque formation by cell-free VZV. Toxicity assays with human diploid embryo fibroblast cells were also carried out. Drug concentrations as high as 800 muM were not toxic to human diploid embryo fibroblast cells as determined by radiolabeling of cell deoxyribonucleic acid, ribonucleic acid, and protein.

Arabinonucleosides↗
PubMed1979

Characterization of pyrimidine deoxyribonucleoside kinase (thymidine kinase) and thymidylate kinase as a multifunctional enzyme in cells transformed by herpes simplex virus type 1 and in cells infected with mutant strains of herpes simplex virus.

Pyrimidine deoxyribonucleoside kinase (thymidine kinase [TK]) was purified from two herpes simplex virus type 1 (HVS-1)-transformed TK-deficient mouse (LMTK-) cell lines and from LMTK- cells infected with HSV-1 mutant viruses coding for variant TK enzymes. These preparations exhibited normal or variant virus-induced thymidylate kinase activities correlating with their relative TK activities. Neither virus-induced activity was detected in LMTK- cells infected with an HSV-1 TK-deficient mutant. These results suggest that HSV-1 thymidylate kinase activity and TK activity are mediated by the same protein.

Animals↗