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Biomedical subjects

Y Azuma

Publications and source records attributed to Y Azuma.

At least 217 records · Page 12Linked to original sources
PubMed1979

Experimental gingivitis in ODU plaque-susceptible rats. III. Toxic activity of the rat dental plaque.

The toxicity tests of the dental plaque from ODU plaque-susceptible rats showed strong lethal effect on mice, and abscess forming effect on guinea-pigs. Bacterial cells isolated from the rat dental plaque also showed strong toxicity on both animals and capillary permeable activity on rabbits. Among these bacterial cells, Corynebacterium showed the strongest toxic effects on these animals. These facts suggested an important role of the dental plaque on initiation and development of gingivitis and that especially Corynebacterium may play an important role on gingivitis in ODU plaque-susceptible rats.

Animals↗
PubMed1978

Phosphodiesterase and its Ca2+-dependent activating factor in bovine thyroid.

Properties of cyclic 3',5'-nucleotide phosphodiesterase in the 100,500 X g supernatant of the bovine thyroid were investigated. The enzyme activity was measured by a radioisotopic method using an anionic-exchange resin, and it was found that the activity was stimulated by Mg2+. Sephadex G-200 gel filtration separated the supernatant into an activating factor, which required the presence of Ca2+, and an enzyme form dependent on the factor. The molecular weights were estimated to be 25,000 and 130,000, respectively. There appeared to be another enzyme form of cAMP phosphodiesterase with different dependence on the activating factor as suggested by gel filtration, but this enzyme form could not be clearly separated. cGMP phosphodiesterase purified by gel filtration showed biphasic kinetic behavior in the absence of Ca2+ and the activating factor, whereas, in their presence, the Lineweaver-Burk plot gave a single Km. The activating mechanism of phosphodiesterase may play a role in the control of concentrations of intracellular cyclic 3',5'-nucleotides in the bovine thyroid.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1978

Experimental gingivitis in ODU plaque-susceptible rats. II. Biochemical nature of the rat plaque.

The characterization of the dental plaque from ODU plaque-susceptible rats is reported. The comparison between the rat dental plaque and a human dental plaque indicates that content of extractable hexose and inorganic salts and amino acid composition are different from each other. Electron microscopic study indicates that bacterial flora of the rat dental plaque seems to be little different from a human dental plaque. In spite spite of obvious differences in biochemical nature between the rat dental plaque and the human dental plaque, there are enough similarities to warrant intensive investigation regarding the relationship between the dental plaque and gingivitis.

Amino Acids↗
PubMed1977

Experimental gingivitis in ODU plaque-susceptible rats. I. Changes of plaque formation and body weight.

New strains of ODU plaque-susceptible and resistant rats have been developed starting from litter mating at our laboratory, in 1972. Those strains were selected and mated for further generations. ODU plaque-susceptible and resistant rats are those that show the presence or absence of plaque formation in their gingiva of lower incisors after they are fed a commercially available powder diet. Experiments were started when rats weighing 75 to 85 gm were about 5 weeks old being fed with 20 gm of a powder diet a day. Almost every 4 days, plaque formation was observed in terms of 5 degrees from zero to 4 degrees and body weight. As a result, plaque formation in plaque-susceptible and resistant rats clearly showed their quality in their 3rd generation. Those qualities will be further emphasized as the generation advances. In the 3rd generation of plaque-susceptible rats, no difference was found in growth between those ingested with a powder diet and those with a solid diet of the same ingredients. But in the first 2 months, male plaque-resistant rats of the 3rd generation grew more quickly than susceptible rats.

Animals↗
PubMed1975

A simple simulation model of tuberculosis epidemiology for use without large-scale computers.

A large-scale computer service is not always available in many countries with tuberculosis problems needing epidemiological analysis. To facilitate work in such countries, a simple epidemiological model was made to calculate annual trends in the prevalence and incidence of tuberculosis and its infection, in tuberculosis mortality, and in BCG coverage, using average parameter values not specific for age groups or birth year cohorts. To test its approximation capabilities and limits, the model was applied to epidemiological data from Japan, where sufficient information was available from repeated nation-wide sample surveys and national statistics. The approximation was found to be satisfactory within certain limits. The model is best used with a desk-top computer, but the calculations can be performed with a small calculator or even by hand.

BCG Vaccine↗
PubMed1975

Urinary excretion of steroids and response to oophorectomy in premenopausal women with advanced breast cancer.

Relationship between the urinary excretion of steroids in premenopausal Japaneses patients with advanced breast cancer and their response to oophorectomy was studied. The estrogen fractions were determined by radioimmunoassay and those who responded to oophorectomy showed higher levels of 17 beta-estradiol than the non-responders before surgery. The high levels of urinary 17 beta-estradiol of the responders dropped markedly after oophorectomy. On the contrary, the non-responders showed relatively low levels of urinary excretion of 17 beta-estradiol before oophorectomy and the levels appeared either unchanged or slightly elevated after surgery. No definite relation was found between changes in the urinary excretion of estrone or estriol and the clinical effect of oophorectomy. Excretion of 17-ketosteroids in the responders was lower than that of the non-responders.

17-Hydroxycorticosteroids↗
PubMed1975

Comparison of the activities for polypeptide synthesis of polysomes prepared with different detergents from normal and regenerating rat liver.

When prepared in the presence of deoxycholate, the activities for polypeptide synthesis of polysomes from normal and regenerating rat liver were similar. However, when the polysomes were prepared in the presence of either Triton X-100 or Lubrol WX, the polysomes from regenerating liver had about three to four times more activity than those from normal liver. On the other hand, the activities for polyphenylalanine synthesis of ribosomes from regenerating rat liver were similar irrespective of whether these ribosomes were prepared in the presence of deoxycholate or Triton X-100.

Animals↗
PubMed1975

[Distribution of bleomycin in sesame oil suspension in organs of rat with mammary carcinoma induced by 7,12-dimethylbenz (a) anthracene and its effect on the tumors (author's transl)].

Distribution of the bleomycin A2 suspended in sesame oil (Oil Bleo Suspension) in rat organs and tumors after the intramuscular administration was investigated by bioassay, the effect of intratumor administration of the suspension on the growth of rat mammary carcinoma induced by 7, 12-dimethylbenz (a) anthracene was also studied. The oil suspension showed a protracted concentration in either tumor or organ tissues, but showed similar inhibitory effects on rat mammary carcinoma to those by regular bleomycin solution. Further studies should be performed on the effect of bleomycin A, in sesami oil on mammary carcinoma.

9,10-Dimethyl-1,2-benzanthracene↗