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Biomedical subjects

Y Osada

Publications and source records attributed to Y Osada.

At least 145 records · Page 8Linked to original sources

Stimulation of non-specific resistance to infection by muroctasin.

The profile of the stimulant activity of a muramyl dipeptide (MDP) analog, N2-[(N-acetylmuramoyl)-L-alanyl-D-isoglutaminyl]-N6-stearoyl-L-lysine (MDP-Lys(L18), muroctasin) on the host resistance to infection was clarified through the following results. A comparative study of parent MDP and MDP-Lys(L18) in relation to the protection against infection with various pathogens revealed the same spectrum of antiinfectious activity, but a different potency: the greater strength of MDP-Lys(L18) was demonstrated both by the smaller influence of bacterial inoculum size on its activity and by the smaller minimal dosage required for inducing significant activity. The superiority of the oral application of MDP-Lys(L18) over MDP was also demonstrated. The protective activity of the compound was substantially influenced by the timing of treatment, the greatest activity being achieved by treatment 1 day before infection. Furthermore, treatment with MDP-Lys(L18) restored the depressed resistance induced by cyclophosphamide to systemic infection with E. coli in mice, and that induced by cortisone acetate to bacteremic pneumonia with P. aeruginosa in guinea pigs. The chemotherapeutic efficacy of antibiotics on E. coli infection was potentiated by combined use of MDP-Lys(L18) for normal mice and mice immunosuppressed with cyclophosphamide. From these findings, enhancement of the host resistance to infection by MDP-Lys(L18) may be an important aspect in the future evaluation of therapy for infection in immunocompromised patients. Finally, since the compound augmented 1. the function of polymorphonuclear leukocytes, such as chemotaxis, phagocytosis, and superoxide anion generating capacity.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylmuramyl-Alanyl-Isoglutamine↗

Penetrability of ofloxacin into cultured epithelial cells and macrophages.

It is well known that the penetration of drugs into host cells is the minimal requirement to exhibit their efficacy against infections with intracellular bacteria. Thus the penetrability of new quinolones including ofloxacin, norfloxacin and ciprofloxacin was evaluated by comparing their intracellular and extracellular activities by the use of cell infection systems in vitro. It was evidenced that the new quinolones tested were penetrable into both epithelial cells and macrophages, however, ofloxacin was more penetrable than norfloxacin and ciprofloxacin into both types of cells which serve the nest for proliferation of intracellular bacteria.

Animals↗

Synergistic generation of tumoricidal macrophages by muroctasin and interferon-gamma.

The ability of N2-[(N-acetylmuramoyl)-L-alanyl-D-isoglutaminyl]-N6-stearoyl-L-lysine (MDP-Lys(L18), muroctasin), a synthetic muramyl dipeptide derivative, to generate tumoricidal macrophages was investigated. MDP-Lys(L18) alone at the dose employed, 100 ng/ml, did not activate macrophages, and by combination with interferon-gamma (IFN-gamma), synergistically generated tumoricidal macrophages. Priming by IFN-gamma of macrophages enhanced endocytosis of MDP-Lys(L18) by the macrophages, which must be one of the mechanisms of the synergism. Thus, MDP-Lys(L18) is suggested to be a potent macrophage activator.

Acetylmuramyl-Alanyl-Isoglutamine↗

Stimulation of plasma fibronectin production in mice by muroctasin.

The production of plasma fibronectin (PFN) in mice treated subcutaneously with N2-[(N-acetylmuramoyl)-L-alanyl-D-isoglutaminyl]-N6-stearoyl-L-lysine (MDP-Lys(L18), muroctasin), was examined. The plasma levels of PFN in mice increased significantly by treatment with a single dose of 10 to 100 micrograms/mouse of MDP-Lys(L18). A slight strain difference in the PFN levels among Std: ddY, C3H/He, and DBA 2 mice was observed: the percent increases at the maximal level in Std: ddY, C3H/He, and DBA/2 mice were 21.6, 19.9, and 10.4, respectively. In Std: ddY mice, the concentration of PFN reached the maximal level at 15 h post-treatment, and decreased gradually of the normal level by 48 h. These results indicate that MDP-Lys(L18) stimulates the PFN production in mice.

Acetylmuramyl-Alanyl-Isoglutamine↗

Beneficial effect of muroctasin on experimental leukopenia induced by cyclophosphamide or irradiation in mice.

Subcutaneous injection of N2-[N-acetylmuramoyl)-L-alanyl-D-isoglutaminyl]-N6-stearoyl-L-lysine (MDP-Lys(L18), muroctasin), a synthetic muramyl dipeptide derivative, favoured recovery of mice from experimental leukopenia induced by cyclophosphamide or by irradiation with X-rays. These effects were observed only when MDP-Lys(L18) treatment occurred after cyclophosphamide injection or X-ray irradiation. Prophylactic treatment resulted in neither preventive nor restorative efficacy on leukopenia. In contrast, glutathione was hardly effective on leukopenia in both models, irrespective of treatment timing. The restorative efficacy of muroctasin was found to be dose-dependent and to be attributable at least to its augmenting effect on colony-stimulating factor production, followed by the marked proliferation and differentiation of myeloblasts towards mature granulocytes in the bone marrow. These beneficial effects of MDP-Lys(L18) warrant further evaluation of its clinical usefulness.

Acetylmuramyl-Alanyl-Isoglutamine↗

Early intravesical instillation of adriamycin with oral administration of 5-fluorouracil after transurethral resection for superficial bladder cancer: preliminary results.

In all, 199 patients were entered in this study by 21 collaborating hospitals. Patients with superficial transitional cell carcinoma of the bladder were randomized postoperatively into four groups. Group A received early (immediately and 2 days after transurethral resection) instillation of adriamycin (30 mg/30 mg); group B received early instillation of adriamycin with oral administration of 5-fluorouracil (200 mg/day); group C received delayed (7 days after transurethral resection) instillation of adriamycin (30 mg/30 ml); and group D received delayed instillation of adriamycin with oral administration of 5-fluorouracil (200 mg/day). All patients subsequently received instillations weekly for 2 more weeks, and then every 2 weeks for a further 14 weeks. After 4 months, they received one instillation per month for 8 months. 5-Fluorouracil was administered p.o. for 1 year. The postoperative follow-up period was 12 months. After 3 and 6 months there were significant differences in the non-recurrence rates between groups B and C. After 12 months the overall non-recurrence rates were 87.9% in group A, 83.5% in group B, 89.2% in group C, and 82.8% in group D, and there were no significant differences among the four groups. The number of patients entered and the follow-up period are not adequate for firm conclusions, and further studies are necessary. The main side effect was bladder irritation, which was observed in 38.8% of patients in the early instillation groups and in 26.3% of those in the delayed instillation groups. No severe systemic side effects were observed in this study.

Administration, Intravesical↗

Isolation and purification of a rat liver-specific antigen from hepatocyte membrane.

A rat liver-specific antigen (RLSA) solubilized with the nonionic detergent non-anonyl-N-methylglucamide was purified through affinity column chromatography with a monoclonal antibody and by high-performance liquid chromatography with a hydroxylapatite column. The purified RLSA showed a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and its molecular weight was determined to be 105,000 in the presence of 2-mercaptoethanol. The antigen was reactive to the Schiff reagent and contained glucosamine, but not galactosamine, indicating that the RLSA is a glycoprotein containing an asparagine-binding type of sugar chain.

Amino Acids↗

Inhibition of DNA gyrase by optically active ofloxacin.

Inhibition of DNA gyrase activity by optically active ofloxacins was studied and compared with the inhibition of norfloxacin and ciprofloxacin. The (-)-isomer of ofloxacin inhibited the supercoiling activity of gyrase from Micrococcus luteus more effectively than did the (+)-isomer. The 50% inhibitory concentrations of (-)-, (+/-)-, and (+)-ofloxacin; norfloxacin; and ciprofloxacin for gyrase from Escherichia coli were 0.78, 0.98, 7.24, 0.78, and 1.15 microgram/ml, respectively. These values correlated well with the antibacterial activity of each compound against intact bacterial cells.

Anti-Bacterial Agents↗

Modification of the cysteamine side chain of thienamycin. III.

Thienamycin derivatives (4) having a cyclic amidine moiety at the C-2 position were prepared. The susceptibility to renal dehydropeptidase-1 and the antimicrobial activity of these compounds were determined. Their structure-activity relationships are also discussed.

Chemical Phenomena↗

Inhibitory effects of heparin plus cortisone acetate on endothelial cell growth both in cultures and in tumor masses.

A combination of heparin and cortisone acetate significantly inhibited both embryonic angiogenesis and the tumor growth of Lewis lung carcinoma (3LL) transplanted into C57BL/6 mice, although each of these agents used alone affected neither angiogenesis nor tumor growth. On the other hand, this combination neither decreased the number of metastatic foci in the lung nor prolonged the survival time of mice with 3LL. All tumor-bearing mice died of hemothorax due to pulmonary metastases. Cortisone acetate by itself increased metastasis, and addition of heparin did not affect accelerated metastasis. Because an antiangiogenic activity appears independent of metastasis acceleration by cortisone acetate, the use of steroids other than cortisone acetate having no metastasis-promotion effect should be required for an antiangiogenic tumor therapy in the presence of heparin. Heparin plus cortisone acetate prevented the DNA synthesis of cultured vascular endothelial cells but not that of cultured 3LL cells. Additionally, oral administration of this combination decreased the [3H]thymidine labeling of endothelial cells of tumor blood vessels prior to the suppression of tumor growth. The specific inhibition of the growth of endothelial cells by heparin plus cortisone acetate was revealed in both the in vitro and the in vivo tests.

Animals↗

[A case of leprechaunism with cryptorchidism].

A 6-year-old boy whose chief complaint was right undescended testis was referred to our clinic. He had mental retardation, prominent and widely spaced eyes, large and low-set ears, micrognathia, hyperpigmentation and enlarged genitalia. Therefore, he was diagnosed to have Leprechaunism. Leprechaunism is rare and few studies dealing with this disease have been reported in Japan. With a review of the literature, we briefly discuss about the clinical features of Leprechaunism.

Abnormalities, Multiple↗

Augmentation by priming with interferon-gamma of the binding of a muramyl dipeptide derivative to macrophages resulting in synergistic macrophage activation.

Macrophage (MA) activation by recombinant murine interferon-gamma (rMuIFN-gamma) and a synthetic muramyl dipeptide derivative, N alpha-(N-acetylmuramyl-L-alanyl-D-isoglutaminyl)-N epsilon-stearoyl-L-lysine [MDP-Lys(L18)], was examined. The cytostatic activity of MA that had been primed with rMuIFN-gamma against Lewis lung adenocarcinoma cells was augmented extensively by exposure to MDP-Lys(L18) for a minimum of 15 min, though such treatment in the reverse sequence interfered with the effects of rMuIFN-gamma on MA. The binding assays revealed that rMuIFN-gamma bound to MA with an apparent dissociation constant (Kd) of 0.93 X 10(-9) M (16,000 binding molecules/cell), while MDP-Lys(L18) bound nonspecifically and was endocytosed by MA at 37 degrees. The amount of MDP-Lys(L18) bound to the rMuIFN-gamma-primed MA was significantly greater than that bound to the MA without rMuIFN-gamma priming. A small increase in the amount of MDP-Lys(L18) associated with MA was also observed at 4 degrees, but the amount was one order of magnitude less than that at 37 degrees. The binding of rMuIFN-gamma to MA was significantly suppressed by priming with MDP-Lys(L18). These results indicate that the binding of rMuIFN-gamma in preference to MDP-Lys(L18) to MA is of great importance in the mechanisms of MA activation.

Acetylmuramyl-Alanyl-Isoglutamine↗

Lack of effectiveness of ofloxacin against experimental syphilis in rabbits.

Ofloxacin, a new pyridone-carboxylic acid derivative, was evaluated in experimental syphilis in rabbits in comparison with penicillin G. Experimental syphilis was established by intradermal injection of Treponema pallidum subsp. pallidum Nichols. Ten days after infection, the dermal lesions were characterized by syphilitic papula accompanied with central necrosis. These animals were subsequently treated either with ofloxacin twice a day at an oral dose of 10 mg/kg or with penicillin G once a day at an intramuscular dose of 10,000 U/kg for 21 consecutive days. In penicillin G-treated animals, the dermal lesions became smaller as early as day 3 of treatment and almost disappeared during the therapy. In marked contrast to remarkable efficacy of penicillin G was further development of the lesions in ofloxacin-treated animals, showing no difference in pathological manifestations as compared to untreated animals. The results of nontreponemal serologic test correlated well with the response of animals to treatment.

Animals↗

Effect of ascorbic acid on the metabolism of N-nitrosopiperidine.

Guinea-pigs were fed diets containing 48, 200 or 2000 mg/kg ascorbic acid (AsA) for 20-30 days and given a single oral dose of 50 mg N-nitrosopiperidine (NPIP)/kg body weight. The levels of glutaric acid, 3-hydroxy-NPIP and 4-hydroxy-NPIP, but not of 1,5-pentanediol, in urine increased with the dose of AsA in the diet.

Animals↗

Synergistic induction of cytotoxicity in macrophages by murine interferon-gamma and biological response modifiers derived from microorganisms.

The ability of recombinant murine interferon-gamma (rMuIFN-gamma) to activate murine macrophages with or without several biological response modifiers (BRM), including synthetic muramyl dipeptide derivatives (MDPs), was investigated. Mouse peritoneal macrophages were activated by rMuIFN-gamma alone to the cytostatic state, but not the cytolytic state. Other BRM as well as bacterial lipopolysaccharide (LPS), including a lyophilized preparation of an attenuated strain of Streptococcus hemolyticus, a cell wall skeleton of bacillus Calmette-Guerin and synthetic MDPs, were highly active in generating the synergism with rMuIFN-gamma. Macrophages were endowed with the cytolytic activities by combinations of rMuIFN-gamma and MDP-Lys(L18); the combination of 100 U/ml of rMuIFN-gamma with 10 ng/ml of MDP-Lys(L18) was sufficient to induce cytolytic activities in macrophages. The synergism was observed when the macrophages primed with rMuIFN-gamma were treated with LPS or MDP-Lys(L18), but not when the sequence of treatment was reversed. The cytotoxicity of macrophages induced by rMuIFN-gamma with MDP-Lys(L18) was suppressed by priming with MDP-Lys(L18). The suppressive effect was also observed by priming with LPS in combinations of rMUIFN-gamma and LPS. The reason for the suppression of macrophage activation by priming with LPS and MDP-Lys(L18) is at present unknown.

Acetylmuramyl-Alanyl-Isoglutamine↗