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Biomedical subjects

H Bannai

Publications and source records attributed to H Bannai.

25 records · Page 2Linked to original sources
PubMed1990

[Evaluation of in vitro activity of rokitamycin against Chlamydia trachomatis].

Evaluation of the in vitro activity of rokitamycin (RKM) against Chlamydia trachomatis in cycloheximide treated HeLa 229 cells and McCoy cells by comparing with five drugs including doxycycline (DOXY), minocycline (MINO), ofloxacin (OFLX), ampicillin (ABPC) and erythromycin (EM) with regard to assaying minimal inhibitory concentrations (MICs), minimal lethal concentrations (MLCs), and by yield reduction assays: 1) direct treatment of Chlamydial organisms with various concentrations of antibiotics before inoculation, 2) pre-treatment of host cell (HeLa 229) with the antibiotics before they are infected and 3) treatment of already infected cultures (48 hrs after infection) with antibiotics. The yield of Chlamydia was determined by both assaying the infectivity of Chlamydia and/or Chlamydiazyme value (from Abott Co Ltd USA). It was found that similar MIC was obtained among the drugs tested (except EM) in both HeLa 229 cell and McCoy cell assay system. The MLC of RKM (0.3 micrograms/ml) was the same as that of OFLX and was significantly lower than that of other drugs tested. When Chlamydial organisms and the host cells were treated with various concentrations (25-0.1 micrograms/ml) of the drug, the infectivity and the growth of Chlamydia was noteworthily decreased with RKM treatment. Infectivity of Chlamydia in an already infected cultures also decreased with RKM treatment within 24 hours when comparing the value of the control. In other drugs treatment, 96 hours or more hours were required for obtaining the same infectivity as RKM.(ABSTRACT TRUNCATED AT 250 WORDS)

Cells, Cultured↗
PubMed1989

[Immune response against Chlamydia trachomatis inoculation in mice--changes in interferon activity, antibody titers and weight of the spleen as parameters of infection].

We examined the immune response against Chlamydia trachomatis (serovar L2) inoculation in mice by measuring the serum interferon (IFN) level, 2'-5'A synthetase (2-5A(S] activity, antibody titers (IgM, IgG) and the spleen weight as parameters of infection. The interferon activity was detected 6 hrs (400 U/ml) and the activity peaked 12 hrs (450 U/ml) after inoculation, and then gradually decreased thereafter (24 hrs: 12 U/ml, 36 hrs: undetectable). It was found that Chlamydia trachomatis induces IFN as well as bacteria. To monitor the behavior of IFN action after serum IFN was cleared, 2-5A(S) activity in the spleen cell extract was measured. It was found that the activity reached its peak 1 to 2 days after inoculation and then decreased as well as in infectivity of Chlamydia trachomatis. The activity however was almost not detected in sera of mice after inoculation of heat-inactivated Chlamydial organism (56 degrees C, 10 min). This may indicate that intact Chlamydial organisms were required for induction of IFN. IFN induced in mice was stable in pH 2.0 treatment and IFN induced by Newcastle disease virus inhibited growth of Chlamydia trachomatis in L929 cell cultures in a dose-dependent manner. The weight of the spleen gradually increased and reached its peak (2- to 3-fold of the control) in 3 to 5 days after inoculation, and then gradually decreased to the control level. IgM and IgG antibodies to Chlamydia trachomatis were detected by immunofluorescence method and enzyme-linked immunosorbent assay, respectively. The antibody IgM was detected as early as 2 days and reached its peak 3 to 4 days after inoculation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Effect of glucose on antiviral activity of interferon.

Glucose was found to impair the antiviral activity of rabbit interferon (IFN) in RK-13 cells. This impairment was dependent on the glucose concentration: A pronounced impairment was observed at the concentration of 30 mg of glucose/ml, the maximum concentration which produced neither morphological changes of cells nor diminution of overall macromolecular synthesis. Maximal impairment was seen when glucose was added to the IFN-treated RK-13 cells early during the development of antiviral activity. Furthermore, glucose decreased the extent of induction of 2',5'-oligoadenylate synthetase by IFN. Of six different monosaccharides examined, only fructose had the same anti-IFN effect as glucose.

2',5'-Oligoadenylate Synthetase↗
PubMed1985

Pharmacokinetic study of a human recombinant interferon (Re-IFN-alpha A) in cynomolgus monkeys by 2'-5' oligoadenylate synthetase assay.

We evaluated 2'-5'Oligoadenylate (2-5 A) synthetase assay for pharmacokinetic study of human interferon (IFN) in cynomolgus monkeys. The enzyme was induced in primary cultures of cynomolgus monkey kidney (PMK) cells as well as in FL cells in response to human recombinant IFN-alpha A treatment. The enzyme activity increased with IFN dose and, in parallel with the enzyme elevation, developed the antiviral state of the cells. The enzyme activity induced in the peripheral blood lymphocytes peaked at 6 to 12 hr after iv or im administration. The peak level of the enzyme activity depended on the IFN concentration of the blood and the activity rapidly decreased as serum IFN was cleared from the blood. These results indicate that human recombinant IFN-alpha A induces 2-5 A synthetase in monkey cells both in vitro and in vivo, and that the enzyme assay can be used to quantitatively monitor the host response after IFN administration.

2',5'-Oligoadenylate Synthetase↗
PubMedDate not supplied

Comparison of pharmacokinetic behaviors of two human interferons (Lb-IFN-alpha and Re-IFN-alpha A) in cynomolgus monkeys by 2'-5' oligoadenylate synthetase assay.

Two human interferons (IFNs), natural lymphoblastoid IFN-alpha (Lb-IFN-alpha) and recombinant IFN-alpha (Re-IFN-alpha A) were compared for their induction of 2'-5' oligoadenylate (2-5A) synthetase and pharmacokinetic behaviors in cynomolgus monkeys. In in vitro experiments, the enzyme activity induced in an epithelial cell strain from human amniotic membrane (FL) cells was much higher than that in primary culture of cynomolgus monkey kidney (PMK) cells, and Lb-IFN-alpha induced higher levels of the enzyme than did Re-IFN-alpha A in both cells. In in vivo experiments, no difference was found in clearance from the blood between the two IFNs, but the half life of the enzyme induced in peripheral leukocytes by Lb-IFN-alpha was about twice longer than that by Re-IFN-alpha A, and the enzyme levels detected in various tissues were IFN-dose dependent. These results indicate that natural Lb-IFN-alpha is more effective in inducing 2-5A synthetase than Re-IFN-alpha A, and that the enzyme activity of various tissues as well as peripheral blood lymphocytes (PBL) increased in the cynomolgus monkeys administered with human IFNs.

2',5'-Oligoadenylate Synthetase↗