Search PubMed⌕ Search

Biomedical subjects

M Saneyoshi

Publications and source records attributed to M Saneyoshi.

At least 73 records · Page 4Linked to original sources
PubMed1989

Antitumor activity and pharmacology of 1-beta-D-arabinofuranosylcytosine-5'-stearylphosphate: an orally active derivative of 1-beta-D-arabinofuranosylcytosine.

The antitumor activity of 1-beta-D-arabinofuranosylcytosine-5'-alkylphosphates (CnPCAs) against L1210 leukemia in mice after oral administration was demonstrated. The optimum length of the alkyl group on the phosphate moiety of CnPCA for exhibiting a high antitumor activity was found to be between tetradecyl (C14) and tricosyl (C23). The most active alkyl derivative in this system was found to be 1-beta-D-arabinofuranosylcytosine-5'-stearylphosphate (C18PCA). The optimum and minimum effective doses of C18PCA were 100 and 6.25 mg/kg/day (q1d, day 1 to day 5), respectively. The maximum T/C% of C18PCA was approximately 220. The antitumor activity of C18PCA was not greatly dependent on the treatment schedule and route. Plasma concentration of 1-beta-D-arabinofuranosylcytosine (ara-C) remained in the range of 0.4 to 0.75 nmol/ml [corrected] for 24 h after oral administration of 100 mg/kg (170 mumol/kg) of C18PCA. These results indicate that C18PCA administered per orally is absorbed intact through the gastrointestinal tract and area-C is released of long period of time. C18PCA is regarded as an orally active depot form of ara-C.

Administration, Oral↗
PubMed1989

In vitro bone marrow toxicity of nucleoside analogs against human immunodeficiency virus.

3'-Azido-2',3'-dideoxythymidine is known to cause severe anemia and neutropenia. Although these are rare for 2',3'-dideoxycytidine, it frequently impairs thrombocytogenesis. These differential myelossuppressive features correlated well with the in vitro toxicities of the drugs for a megakaryoblastic cell line and for colony formation of erythroid and granulocytic cells.

Antiviral Agents↗
PubMed1989

Antiviral activities and the mechanism of 9-beta-D-ribofuranosyl-6-alkylthiopurines on several RNA viruses from animals.

A series of 9-beta-D-ribofuranosyl-6-alkylthiopurines (6-alkyl TI) were found to inhibit in vitro replication of infectious hematopoietic necrosis virus (IHNV), human influenza virus (IFV) and respiratory syncytial virus (RSV) with IC50 values of about 0.06 microgram/ml, 0.7-1.5 micrograms/ml and 1-3 micrograms/ml, respectively. Viral RNA synthesis in infected cells in the presence of actinomycin D was inhibited by treatment with the compounds dose-dependently. It was also found that the decrease of rNTP pool size in infected cells was remarkably dose-dependent. From these findings, the mode of antiviral action of these compounds may be explained by rNTP imbalance in the treated group.

Antiviral Agents↗
PubMed1988

Potentiation of the antitumor effect of 5-fluoro-2'-deoxyuridine esters in combination with acyclothymidine esters on L1210 in mice via oral administration.

Fifteen pyrimidine-related compounds were evaluated for their ability to inhibit enzymatic degradation of 5-fluoro-2'-deoxyuridine (FUdR). Acyclothymidine [5-methyl-1-(2'-hydroxyethoxymethyl)uracil] showed the highest inhibitory effect on the phosphorolytic degradation of FUdR in various tissue homogenates derived from mouse, rat, and beagle organs. Both the drug (FUdR) and the inhibitor (acyclothymidine) were esterified with appropriate aliphatic acids in order to synchronize their behavior after simultaneous oral administration. The antitumor activity of orally administered FUdR esters was potentiated by the simultaneous oral administration of the acyclothymidine esters, but not by acyclothymidine.

Animals↗
PubMed1988

AraUTP-Affi-Gel 10: a novel affinity absorbent for the specific purification of DNA polymerase alpha-primase.

For the specific purification of eukaryotic DNA-dependent DNA polymerase alpha, we prepared two novel affinity resins bearing 5-(E)-(4-aminostyryl) araUTP as a ligand. One of them was araUTP-Sepharose 4B which was coupled directly with the ligand and the other was araUTP-Affi-Gel 10 which was coupled with the ligand through a spacer. No DNA polymerase alpha-primase activity from cherry salmon (Oncorhynchus masou) testes was bound on the araUTP-Sepharose 4B in all cases examined. On the other hand, the araUTP-Affi-Gel 10 retains this enzyme activity when poly(dA) or poly(dA)-oligo(dT)12-18 is present. The retained enzyme activity was sharply eluted around 100-mM KCl concentrations as a single peak, and this fraction showed a specific activity of about 170,000 units/mg as alpha-polymerase activity. The highly purified DNA polymerase alpha-primase isolated using the araUTP-Affi-Gel 10 contained only three polypeptides, which showed Mr values of 120,000, 62,000, and 58,000, respectively, as judged using sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

Animals↗
PubMed1988

Inhibitory effect of sulphur-containing purine nucleoside analogues on replication of RNA viruses: selective antiviral activity against influenza viruses.

Four sulphur-containing purine nucleoside analogues: 6MP, 6-thioinosine, 6-methylthioinosine and 6-ethylthioinosine, were examined for antiviral activity against some RNA viruses. All compounds extensively inhibited the replication of influenza viruses but had no inhibitory effect on other RNA viruses: Sendai, RS, vesicular stomatitis and western equine encephalitis viruses.

Amidophosphoribosyltransferase↗
PubMed1987

Antiviral activity of various 1-beta-D-arabinofuranosyl-E-5-halogenovinyluracils and E-5-bromovinyl-2'-deoxyuridine against salmon herpes virus, Oncorhynchus masou virus (OMV).

1-beta-D-Arabinofuranosyl-E-5-bromovinyluracil (BVaraU), 1-beta-D-arabinofuranosyl-E-5-iodovinyluracil (IVaraU), 1-beta-D-arabinofuranosyl-E-5-chlorovinyluracil (CVaraU) and 1-beta-D-arabinofuranosyl-5-vinyluracil (VaraU) were examined for antiviral activity against salmon herpesvirus, Oncorhynchus masou virus (OMV) in vitro using Yamame (Oncorhynchus masou) kidney cells (YNK). BVaraU, IVaraU, CVaraU and VaraU were highly active against OMV; 50% inhibitory concentration (IC50): 0.01, 0.003, 0.003, 0.003 microgram/ml, respectively. The IC50 of 5-bromovinyl-2'-deoxyuridine (BVDU) was 0.3 microgram/ml. The lower activity may be due to cleavage of it N-glycosyl linkage by pyrimidine nucleoside phosphorylases (i.e. thymidine phosphorylase) during the incubation period. The arabinofuranosyl counterparts are resistant to this (these) enzyme(s). Both OMV-induced DNA polymerase and cellular DNA polymerase alpha were strongly inhibited by BVaraU 5'-triphosphate (BVaraUTP). In an in vivo study, daily immersion of OMV-infected chum salmon (Oncorhynchus keta) fry into aqueous solution of BVaraU (5 micrograms/ml, 30 min/day, 30 times) did not increase the life span of infected fish.

Animals↗
PubMed1987

Inhibitory effects of 5-alkyl- and 5-alkenyl-1-beta-D-arabinofuranosyluracil 5'-triphosphates on herpes virus-induced DNA polymerases.

Various 5-substituted 1-beta-D-arabinofuranosyluracil 5'-triphosphates (H, methyl, ethyl, n-propyl, n-butyl, (E)-bromovinyl, styryl, and beta-phenylethyl derivatives) were prepared and their inhibitory effects on two different herpes virus-induced DNA polymerases (OMV and HCMV) were studied. These dTTP analogues inhibited the incorporation of [3H]dTMP into DNA in vitro. Among them, analogues having a vinyl group at the 5-position were strongly active against DNA polymerases induced on herpes virus infection. Kinetic analysis showed that the inhibition by the analogues was essentially competitive with respect to the substrate, dTTP. The K1 values (microM) for AraUTP (2.4), AraTTP (1.0), BVAUTP (0.8), and StUAUTP (0.8) were smaller than the Km value (microM) for dTTP (3.4), but those for AraEtUTP, AraPrUTP, and AraBuUTP (5-14) were larger than the Km for dTTP in the case of HCMV-induced DNA polymerase. In contrast to these results, OMV-induced DNA polymerase seemed to be more resistant to these inhibitors than HCMV-induced DNA polymerase. However, the mode of the structure of substituent groups at the 5-position of base moieties is almost the same for the two DNA polymerases, except for in the case of AraUTP itself.

Antiviral Agents↗
PubMed1986

Inhibition of reverse transcriptase activity by 2',3'-dideoxythymidine 5'-triphosphate and its derivatives modified on the 3' position.

Inhibitory effects of 2',3'-dideoxythymidine 5'-triphosphate (ddTTP) and its three derivatives modified on the 3' position of ribose moiety [3'-azido-2',3'-dideoxythymidine 5'-triphosphate (3'-N3-ddTTP), 3'-amino-2',3'-dideoxythymidine 5'-triphosphate (3'-NH2-ddTTP) and 2'-deoxyxylo-furanosylthymine 5'-triphosphate (dXTP)] on the activity of the reverse transcriptase purified from Rauscher murine leukemia virus were examined and compared with each other. When (rA)n X (dT)12-18 was used as the template X primer in the presence of manganese ion, all these compounds except 3'-NH2-ddTTP inhibited the reverse transcriptase activity in competitive fashion with respect to the dTTP substrate. The inhibition potentials of these compounds are ordered as follows: 3'-N3-ddTTP (Ki = 1.8 microM) greater than ddTTP (Ki = 9.3 microM) greater than dXTP (Ki = 16.3 microM), and the Ki values of these inhibitors are smaller than the Km of dTTP (30 microM). The observed inhibitions were mainly due to competition between the dTTP substrate and inhibitor rather than chain-termination of the elongating DNAs caused by incorporation of these dideoxy compounds.

Binding, Competitive↗
PubMed1986

Characterization of DNA polymerase induced by salmon herpesvirus, Oncorhynchus masou virus.

A DNA polymerase induced by Oncorhynchus masou virus (OMV) was isolated from cultured salmon cells infected with OMV using sequential ion-exchange column chromatography steps. The properties of the OMV polymerase were compared to those of human cytomegalovirus (HCMV) polymerase and polymerase alpha from cherry salmon (masu salmon, O. masou) testes. OMV polymerase was clearly distinguished from the other polymerases by its optimum temperature for enzyme activity, 25 degrees C. In an investigation of the effects of phosphonoacetic acid and aphidicolin, OMV polymerase was found to be more resistant to both drugs than HCMV polymerase.

Animals↗
PubMed1986

The synergism of nucleoside antibiotics combined with guanine 7-N-oxide against a rhabdovirus, infectious hematopoietic necrosis virus (IHNV).

Guanine 7-N-oxide was shown to have synergistic activity in combination with neplanocin A against a rhabdovirus, infectious hematopoietic necrosis virus (IHNV), as reported previously. We examined further the antiviral activity of guanine 7-N-oxide in combination with other nucleoside antibiotics against IHNV. Synergism was seen between guanine 7-N-oxide and D-eritadenine or cordycepin. It is considered that compounds inhibiting RNA methylation show synergism with guanine 7-N-oxide.

Anti-Bacterial Agents↗
PubMed1986

Potentiation by acyclothymidine esters of the antitumor effect of orally administered 5-fluoro-2'-deoxyuridine esters on L1210 in mice.

The antitumor effect of 5-fluoro-2'-deoxyuridine (FUdR) esters on L1210 in mice was enhanced by the simultaneous po administration of FUdR esters and acyclothymidine [5-methyl-1-(2'-hydroxyethoxymethyl)uracil]-esters. Acyclothymidine (AcTdR), which strongly inhibits the phospholytic degradation of FUdR, was released from the AcTdR esters by enzymatic hydrolysis. The FUdR esters and AcTdR esters were found to be compatible in terms of their physicochemical properties and susceptibility to enzymatic hydrolysis.

Administration, Oral↗