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Biomedical subjects

A Ohyama

Publications and source records attributed to A Ohyama.

68 records · Page 4Linked to original sources
PubMed1986

[Flow cytometric studies of brain tumors--5: New sensitivity test of antineoplastic agents for brain tumors and its clinical application].

Flow cytometry (FCM) has been used not only for the judgement of malignant tumor cells but also for the evaluation of chemotherapy. Recently, we established a new application of FCM for the choice of the best antineoplastic agent in the chemotherapy of brain tumor. At first, the system of sensitivity test was developed through the preliminary study using established brain tumor cell line. Antineoplastic agents were contacted with the cells in the monolayered culture and the cell viability and the changes of DNA-histogram were analyzed by FCM. The cell viability was measured with the staining of fluorescein diacetate, and DNA-histogram was analyzed by the staining of propidium iodide. The best agent was judged based on the changes of the cell viability and cell cycle. The cytocidal and cytostatic effects were evaluated quantitatively, showing coincidence with the sensitivity of the cells to the appropriate antineoplastic agent. Secondary, this system was applied for the 15 malignant tumor cases. In these cases, the best antineoplastic agent could be selected through this method. Present system will be applied for the clinical cases continuously. Sensitivity test by FCM could be established in vitro system, and will be of much value clinically.

Animals↗
PubMed1985

The quantitative kinetic study of dengue viral antigen by flow cytometry. I. An in vitro study.

A system effective in the early diagnosis of Dengue virus infection was developed. The time course kinetics of Dengue virus type 2 (D-2) antigen in vitro were analyzed by Flow Cytometry. Early profiles of D-2 were also studied quantitatively through this method of analysis. The early events of host cell and virus interaction were investigated: attachment, internalization and replication. From these early profiles, the time at which new viral synthesis was detectable differed with each individual trial. These different times were found to be dependent of the phase of the cell cycle. From these results we could detect newly synthesized viral antigen within 10 h after infection.

Aedes↗
PubMed1985

Antineoplastic effects in rats of 5-fluorocytosine in combination with cytosine deaminase capsules.

5-Fluorocytosine (5-FC) lacks antineoplastic activity in human subjects because of the absence of cytosine deaminase (CDase) in mammalian cells. Intratumoral conversion of 5-FC into 5-fluorouracil (5-FUra) by locally implanted capsules containing CDase followed by systemic administration of 5-FC can be expected to induce antineoplastic activity at a local site with minimal systemic toxicity. In vitro and in vivo experiments were performed to evaluate this hypothesis. Spectrophotometric analysis confirmed the deamination of 5-FC to 5-FUra by CDase extracted from cultivated Escherichia coli. In vitro studies showed that 5-FC combined with CDase induced significant growth-inhibitory effects on the cultured glioma cells. An active CDase capsule, made of cellulose tubing, was newly designed for local implantation. 5-FC concentrations in the s.c. tumors of the rats given these CDase capsules, followed by 5-FC administration, showed a sufficient amount of delivery of 5-FC to the tumor tissue. 5-FUra appearing in the tumor reached the level of 8.0 micrograms/g at 2 h and stayed at more than 1.0 microgram/g at between 1 and 6 h. Significant reduction of the tumor growth and cytotoxic changes were observed. The passive cutaneous anaphylaxis reaction demonstrated no allergic reaction to the host due to the capsule. These results suggest that this chemotherapeutic method is effective for human brain tumors.

Animals↗
PubMed1981

Evaluation of 36 Minitek tests and a new approach for identification of nonfermenters.

Thirty-six Minitek (BBL Microbiology Systems, Cockeysville, Md.) tests were evaluated with 625 Kansai Medical University stock strains of 22 species and one group of nonfermentative gram-negative rods able to grow on ordinary peptone media. Among the 36 tests, 15 were selected because a clear-cut reaction was shown by all 625 Kansai Medical University strains. Of these 15 tests, 12 were further selected for routine use because they were regarded as useful for the identification of nonfermenters. The 12 tests were arranged into the following four groups: (i) lysine-arginine-ornithine, (ii) urea-ortho-nitrophenyl-beta-D-galactopyranoside-dextrose aerobic, (iii) maltose-xylose-starch, and (iv) esculin-nitrate reduction-indole. A new profile system for four digits, the Minitek Y-Y (Yabuuchi and Yamanaka) system, consisting of 64 numbers which represent each single species and 11 numbers which give two to four species, is herein proposed. The system was designed primarily for a less expensive identification of gram-negative rods already confirmed in a butt of either triple sugar iron or Kligler iron agar for their lack of ability to ferment dextrose. Among the 539 clinical isolates obtained from 3 hospitals, 511 strains identifiable by classical methods were also identified by the Minitek Y-Y system.

Amino Acids↗