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Biomedical subjects

A Honda

Publications and source records attributed to A Honda.

At least 199 records · Page 11Linked to original sources
PubMed1987

Identification of the RNA polymerase-binding site on genome RNA of influenza virus.

The binding sites for influenza viral RNA polymerase on genome RNA segments were investigated. Ribonucleoprotein (RNP) cores containing the RNA polymerase were isolated from detergent-treated virions by glycerol gradient centrifugation. On ApG-primed in vitro transcription by the isolated RNP cores, different levels of RNA transcripts were synthesized for the eight RNP cores, suggesting an uneven distribution of the RNA polymerase. 3'-Terminal labeling of the RNP cores with the use of [32P]pCp and T4-RNA ligase indicated a reciprocal correlation between the levels of the RNA-3' label and RNA synthesis. Centrifugation of detergent-treated virions in a double gradient of cesium trifluoroacetate (or cesium chloride) and glycerol yielded RNA polymerase-RNA complexes devoid of NP, the major RNA-bound protein, but the pattern of RNA-3' labeling remained virtually unaffected. All these observations together indicated that the RNA polymerase is associated near the 3' termini of some viral RNA segments, thereby preventing the in vitro labeling of the RNA-3' ends. The results of foot-printing experiments using RNase V1 and RNase T2 were in agreement with this model.

Adenosine Monophosphate↗
PubMed1987

Allergic predisposition among infants with bronchiolitis.

Allergic predisposition among infants with bronchiolitis was examined. The number of infants with serum IgE exceeding mean +1 SD was 31/70 (44.3%). The rate of positive radioallergosorbent test (RAST) scores of 1 or more to mites, egg white, or milk was 31/71 (43.7%) and that of scores over 2 was 11/71 (15.5%). Eosinophils and/or mast cells were found in their nasal smears on several occasions. These results indicated that allergic predisposition may be observed among infants with bronchiolitis.

Acute Disease↗
PubMed1987

Antiproliferative and cytotoxic effects of newly discovered halogenated coral prostanoids from the Japanese stolonifer Clavularia viridis on human myeloid leukemia cells in culture.

The antiproliferative and cytotoxic activities of newly discovered halogenated coral prostanoids (chlorovulone, bromovulone, and iodovulone) from the Japanese stolonifer Clavularia viridis and their related compounds were determined in HL-60 cells in culture. The order of antiproliferative and cytotoxic activities of naturally occurring marine prostanoids against HL-60 cells was chlorovulone I greater than bromovulone I = iodovulone I greater than clavulone I or II greater than prostaglandin A2. The IC50 (concentrations required to inhibit cell growth by 50%) value (0.03 microM (0.01 microgram/ml)) and cytotoxic effects (greater than 0.3 microM (0.1 microgram/ml)) of chlorovulone I were about 200 and 100 times stronger than those of prostaglandin A2, respectively, on the molar basis. From our data on the structure-activity relationship of the halogenated coral prostanoids and the related compounds, we elucidated that 1) the alkylidencyclopentenone structure in these prostanoids was essential for the antiproliferative and cytotoxic activities against HL-60 cells and the introduction of halogen function at C-10 position in the structure enhanced the activities (C1 = F greater than Br = I greater than H); 2) the stereospecificity of the 12-hydroxyl group in the chlorovulone molecule was not required for the activities; 3) the presence of dienone (C5-6 and C7-8) in the structure potentiated the activities. Bivariate DNA/bromodeoxyuridine analysis with a flow cytometer showed that chlorovulone I transiently arrested the cell cycle progression from G1 to S after 24-hr exposure to the nontoxic concentrations (0.03 and 0.09 microM) and caused the lasting blockade of leukemia cells in G1 at the cytotoxic concentration. These results suggest that these coral prostanoids and related compounds may be a promising antileukemic agent.

Animals↗
PubMed1987

[Clinical studies of norfloxacin on respiratory tract infections in aged people].

Norfloxacin (NFLX), an oral antibacterial agent of new quinolone derivative, was administered at daily doses of 300-600 mg t.i.d. to 20 aged patients with respiratory tract infections. The results obtained are summarized as follows. 1. Clinical efficacies were moderate in 6 patients with upper respiratory tract infections, and moderate in 11 patients and fair in 3 patients with lower respiratory tract infections. In the 20 patients, overall clinical efficacies were moderate in 17 patients, hence the efficacy rate was 85%. 2. Bacteriologically, causative organisms were detected in 10 of the 14 cases with lower respiratory tract infections. In these cases, bacteriological responses were "eradicated" in 9 cases, "decreased" in 1 case and "unknown" in 1 case, the rate of eradication was 90%. 3. No adverse reactions or abnormal laboratory test values were observed.

Aged↗
PubMed1987

Enzymatic sulfation of gastric mucous glycoprotein in rat--changes in glycoprotein sulfotransferase activity with stress and anti-ulcer agent, sofalcone.

Enzymatic sulfation of mucous glycoprotein (GP) was studied in gastric mucosa of rat. After rat stomach was incubated with [35S]-sulfate, incorporation of radioactivity into gastric mucosal APS (adenosine 5'-phosphosulfate), PAPS (3'-phosphoadenosine 5'-phosphosulfate) and endogenous GPs could be detected. The degree of sulfation of endogenous GPs was highest in the macromolecular GP (peak I) and lowest in the low molecular GP (peak III). By using a crude preparation of GP sulfotransferase from rat gastric mucosa, the transfer of [35S]-sulfate from [35S]-PAPS into macromolecular mucous GP was determined as being the activity of sulfotransferase. The activity of GP sulfotransferase was mainly distributed in the microsomal fraction, and was proportional to the incubation time, substrate (mucous GP) concentration and [35S]-PAPS concentration. The enzyme activity was significantly higher in the corpus than that in the antral mucosa. The activity of GP sulfotransferase was significantly decreased at 6 h and was significantly increased at 12 h after the stress load, compared with that of the non-stressed condition. Anti-ulcer agent, sofalcone, increased the GP sulfotransferase activity under the stressed condition. On the other hand, cimetidine showed a significant inhibitory effect under the same condition. Changes in the GP sulfotransferase activity with stress and anti-ulcer agents were consistent with those in the incorporation of [35S]-sulfate into macromolecular mucous GP. These results suggest the importance of GP sulfotransferase as a key enzyme regulating the sulfation of mucous GP.

Animals↗
PubMed1987

Detection of fish antibody against protein antigen of Aeromonas salmonicida by enzyme-linked immunosorbent assay using biotin-avidin system.

Antibody against Aeromonas salmonicida was detected in sera from immunised or experimentally infected rainbow trout by enzyme-linked immunosorbent assay (ELISA) using the biotin-avidin system. The ELISA titre correlated well with the agglutinin titres of the sera, but the ELISA was found to be more sensitive than the agglutination test. When the rainbow trout serum was separated by column chromatography, antibody activity (determined by ELISA and agglutination test) was detected in the IgM fractions. Minimum cross reaction was observed in the ELISA system between antigen prepared from A salmonicida and antibodies against Vibrio species and other species of Aeromonas. The specificity of the ELISA was also confirmed by inhibition test. Immunisation of rainbow trout with a virulent strain of A salmonicida provided good protection, though no correlation was observed between the protection and the ELISA titres of sera.

Aeromonas↗
PubMed1986

Proofreading function associated with the RNA-dependent RNA polymerase from influenza virus.

The influenza virus-associated RNA polymerase cleaves capped RNA in an endonucleolytic manner and the transcription is initiated by the addition of GMP, the first substrate to be polymerized under the direction of viral RNA template, onto 3'-termini of resulting capped RNA fragments. In the presence of high concentrations of GTP as a sole substrate, multiple GMP residues were polymerized onto the primers. By the addition of the second substrate CTP, excess GMP residues, other than the 1st residue, were removed prior to elongation. The result may suggest that the RNA-dependent RNA polymerase carries a proofreading function.

Cytidine Monophosphate↗
PubMed1986

Hyaluronic acid in rabbit pericardial fluid and its production by pericardium.

High-Mr (greater than 2 X 10(6)) hyaluronic acid (about 82 micrograms/ml) was found for the first time in rabbit pericardial fluid. Biosynthetic experiments with minced pericardium from rabbit showed that the high-Mr hyaluronic acid in the pericardial fluid was actively synthesized by the pericardium from [3H]glucosamine.

Animals↗
PubMed1986

Appearance of the arachidonic acid metabolic pathway in human promyelocytic leukemia (HL-60) cells during monocytic differentiation: enhancement of thromboxane synthesis by 1 alpha,25-dihydroxyvitamin D-3.

The appearance of the arachidonic acid metabolic pathway in human promyelocytic leukemia (HL-60) cells was investigated during 1 alpha,25-dihydroxyvitamin D-3-induced monocytic differentiation. 1 alpha,25-Dihydroxyvitamin D-3-treated HL-60 cells acquired the ability to convert [1-14C]arachidonic acid to thromboxane B2 and prostaglandin E2 during monocytic differentiation. The major cyclooxygenase product synthesized by the HL-60 cells after 3-4 days exposure to 1 alpha,25- dihydroxyvitamin D-3 (48 nM) was thromboxane B2 and its production was about 19-25-times higher than that of untreated HL-60 cells. The percent conversion of thromboxane B2 from [1-14C]arachidonic acid in the 1 alpha,25-dihydroxyvitamin D-3 (48 nM, 3 day exposure)-treated HL-60 cells was about 4.4% as compared to that (about 0.3%) of the untreated cells, whereas the percent conversion of thromboxane B2 from [1-14C]prostaglandin H2 in the 1 alpha,25-dihydroxyvitamin D-3-treated cell homogenate was about 22.4% as compared to that (about 13.6%) of the untreated cell homogenate. The stimulatory effect of 1 alpha,25-dihydroxyvitamin D-3 on thromboxane B2 production from [1-14C]arachidonic acid and from [1-14C]prostaglandin H2 in HL-60 cells was inhibited by the addition of cycloheximide (1 microgram/ml). However, 1 alpha,25-dihydroxyvitamin D-3 (48 nM) did not significantly stimulate the arachidonic acid release either in HL-60 cells or in 1 alpha,25-dihydroxyvitamin D-3-induced cells. These results suggest that the stimulatory effect of 1 alpha,25-dihydroxyvitamin D-3 on the thromboxane production in HL-60 cells was not due to the activation of phospholipase A2 but due to the induction of fatty acid cyclooxygenase and thromboxane synthetase activities. Thromboxane A2 actively produced during the monocytic differentiation of HL-60 cells could influence the cell adhesiveness of the monocyte-macrophage-differentiated cells.

Arachidonic Acid↗
PubMed1986

RNA polymerase of influenza virus. Dinucleotide-primed initiation of transcription at specific positions on viral RNA.

The priming activities of dinucleotides of all possible base sequences as to the transcription initiation by influenza virus-associated RNA polymerase were investigated. Dinucleotide ApG, complementary to positions 1-2 from the 3' termini of viral RNA segments, was the most active primer and directed the formation of ApGpC; dinucleotide GpC, complementary to positions 2-3, was also an active primer and directed the formation of either GpCpG or GpCpA; but both dinucleotides CpG and CpU, complementary to positions 3-4, were virtually inactive. These results indicate that the transcription is initiated within the first four nucleotides at the 3' termini of viral RNA. Among other dinucleotides, only those hybridizable to viral sequences at their 3'-proximal bases were partially active, implying the essential role of base pairing immediately next to the first phosphodiester bond.

Animals↗
PubMed1986

Genetic studies on the beta subunit of Escherichia coli RNA polymerase. IX. The role of the carboxy-terminus in enzyme assembly.

The assembly of RNA polymerase was studied in Escherichia coli mutants encoding large N-terminal amber fragments of the beta subunit. Whereas the removal of up to 20% of the carboxy-terminus does not prevent the formation of premature core enzyme, the amber fragments seem to interfere with holoenzyme production. These studies permit, therefore, the localization of a region on the beta polypeptide involved in sigma binding.

DNA-Directed RNA Polymerases↗
PubMed1986

Phagocytic activity of macrophages of rainbow trout against Vibrio anguillarum and the opsonising effect of antibody and complement.

The phagocytosis of Vibrio anguillarum by peritoneal macrophages from normal rainbow trout was enhanced by antibody and complement. Treatment of either macrophages or the bacteria by antibody also enhanced opsonisation. Five weeks after immunisation with V anguillarum, the phagocytic activity of macrophages from rainbow trout was increased significantly compared with the activity of those from unvaccinated fish. Although agglutinin titres did not increase until three weeks after immunisation, seven out of 10 fish challenged one week after immunisation survived, indicating that immunised fish had developed resistance to vibrio infection before significant levels of antibody or phagocytic activity became detectable.

Animals↗
PubMed1985

Antileukemic effect of coral-prostanoids clavulones from the stolonifer Clavularia viridis on human myeloid leukemia (HL-60) cells.

To elucidate the biological activities of coral-prostanoids, clavulones, discovered from the Japanese stolonifer Clavularia viridis, we examined the effect of clavulone on the cell growth of human cancer (human promyelocytic leukemia (HL-60) cells and HeLa cells) and normal (Chang liver cells and lung fibroblasts) cells in vitro. Clavulone showed strong antiproliferative and cytotoxic activities in the human cells and it had some selectivity to leukemic (HL-60) cells over other HeLa cells or normal cells on the basis of the IC50 values and cytotoxic effect of the cells. The IC50 value of clavulone in the HL-60 cells was about 0.4 microM (0.2 micrograms/ml). Over 1.0 microM (0.5 micrograms/ml), clavulone showed a significant cytotoxic activity on the HL-60 cells. The data on DNA synthesis and flow cytometric analysis revealed that clavulone arrests the cells in the G1-phase and inhibits the cell growth of HL-60 cells by inhibiting S-phase DNA synthesis. These results suggest that clavulone has a potent antileukemic effect on HL-60 cells.

Antineoplastic Agents↗
PubMed1985

Alterations in glycosaminoglycans of the aorta of vitamin E-deficient rats.

To elucidate whether or not a vitamin E-deficient diet affects the rat aorta extracellular matrix, we examined the alterations in glycosaminoglycans (GAGs), as one of the components of the extracellular matrix of the aorta. The total amount of uronic acid, as an index of GAG, decreased significantly in the aorta of vitamin E-deficient rats. The components of GAG were identified as hyaluronic acid (HA), heparan sulfate (HS), dermatan sulfate (DS) and chondroitin sulfate (CS) by electrophoresis together with enzymic digestion. The amount of sulfated GAGs, especially the amount of DS and CS, decreased in the aorta of vitamin E-deficient rats. The biosynthetic activity of GAG was determined by using [3H]glucosamine and [35S]sulfate. The total biosynthetic activity of GAG and the incorporation of [3H]glucosamine into HA, HS, DS and CS decreased markedly in the aorta of vitamin E-deficient rats. The decrease in the production of sulfated GAGs, especially DS, which is involved in the potent antithrombogenic activity, could be related to the lower anticoagulant activity in the aorta of vitamin E-deficient rats.

Animals↗