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Biomedical subjects

K Ohta

Publications and source records attributed to K Ohta.

At least 793 records · Page 44Linked to original sources
PubMed1984

Morphological changes in the bacterium Bacteroides melaninogenicus subspecies melaninogenicus isolated from the human mouth and grown in culture without added blood components.

Striking polymorphism in the cellular morphology could be induced by removal of blood components from the liquid growth medium, but the cells of Bacteroides gingivalis and B. melaninogenicus subspecies intermedius did not exhibit polymorphism when grown under these conditions. The major changes observed with light microscopy were an increase in cell size and extreme polymorphism. Electron microscopy of the polymorphic forms of B. melaninogenicus subspecies melaninogenicus strains showed that such cells lacked both the outer cell membrane and peptidoglycan layer. Serum promoted the growth of these strains, suggesting that some blood component is either conducive to the synthesis of the cell wall or masks an unknown inhibitor for cell-wall synthesis contained in the medium.

Bacteroides↗
PubMed1984

Bacteriological study of periodontal lesions in two sisters with juvenile periodontitis and their mother.

A total of five bacteriological samples from the periodontal pockets of two sisters with localized juvenile periodontitis and their mother with advanced periodontitis was studied. Gram-negative anaerobic rods were predominant in the samples. Bacteroides intermedius and Bacteroides loescheii were the most predominant species. The antigenicity and bacteriocinogenicity of these isolates were quite similar. Serum immunoglobulin G antibody levels of the subjects to gram-negative periodontopathic bacteria were measured by using the micro-enzyme-linked immunosorbent assay. The levels of antibodies to saccharolytic black-pigmented Bacteroides species were significantly higher than the levels in healthy young females.

Adolescent↗
PubMed1984

Monoclonal antihuman thyroglobulin antibodies.

Six murine hybridomas secreting monoclonal antihuman thyroglobulin (Tg) antibodies (TAK 1-6) were established by cell fusion techniques. Solid phase RIA was employed to detect the anti-Tg antibody in culture supernatants of hybridomas. The characteristics of these monoclonal antibodies were analyzed by radioimmune blocking assay using rat Tg, human glycoproteins, thyroid hormones, and various preparations of Tg obtained from patients with thyroid disease as inhibitors. In the same system, competitive inhibition studies between 125I-labeled and unlabeled monoclonal antibodies were carried out to determine whether these antibodies recognized the same antigenic determinant. TAK 2 and 3 reacted with human Tg specifically and had equal binding activity using various preparations of human Tg. The other four monoclonal antibodies (TAK 1, 4, 5, and 6) cross-reacted with xenogeneic Tg (rat Tg) and their affinity for human Tg increased as the iodine content of Tg increased. Tg binding to TAK 1 and 4 was inhibited by T4, whereas Tg binding to TAK 5 and 6 was not inhibited by any thyroid hormone or their precursors. In conclusion, we prepared six monoclonal antihuman Tg antibodies. One group is specific for human Tg and recognizes the framework structure unmodified by iodination; the second group reacts with iodination-related epitopes other than iodoamino acids, and the third group recognizes determinants consisting of T4. These monoclonal antibodies provide important probes to detect the polymorphism of human Tg.

Animals↗
PubMed1984

Development and evaluation of a new peroral test agent GA-test for assessment of gastric acidity.

A new peroral test capsule, GA-Test, containing riboflavin (5 mg) granules coated with polyvinylacetal diethylaminoacetate (AEA) for assessing gastric acidity without intubation was developed and evaluated for usefulness. GA-Test is based on the tracing in the urine of riboflavin, which is released in the stomach only in the presence of acidic fluid and is absorbed. Due to the film coating, riboflavin released very quickly at a pH of less than 5, and not at all at a pH of greater than 6. GA-Test gave a significant correlation, quantitatively, with peroral Gastrotest in assessing acidity, a non-intubation method which had been marketed in Japan prior to 1980. GA-Test results allowed division of the subjects into two groups i.e., subjects having low (hypo- or anacidity) gastric acidity and those having high (normal or hyperacidity) gastric acidity, GA-Test results agreed well with results of intubation (around 91.4%; 32 out of 35 cases) and were easily reproduced during the evaluation.

Adult↗
PubMed1984

Contraction of guinea pig trachea with antibodies to guinea pig IgE. An in vitro model for asthma. II. Reactivity of guinea pig tracheas to anti IgG1 and anti IgG2 in comparison with anti IgE.

Although relatively small quantities of antibody to guinea pig IgE were shown to contract isolated guinea pig trachea in vitro, relatively large quantities of anti IgG1 were required to elicit similar responses. Under similar conditions, anti IgG2 did not provoke contraction. Following intravenous injection of these antisera into normal guinea pigs, anaphylaxis or asthma could be only provoked by anti IgE.

Animals↗