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Biomedical subjects

K Teramoto

Publications and source records attributed to K Teramoto.

At least 127 records · Page 7Linked to original sources
PubMed1982

[Studies on industrial styrene poisoning (Part XIII). Experimental studies on the damage on the mucosal membrane of respiratory tracts of rats exposed to styrene-contemporary observations of the changes in ciliary function and fine structures].

Styrene is known to have an irritating effect on the tracheal mucosa, but there are few reports that have demonstrated it histologically. We carried out styrene-exposure experiments on rats, and made observations on morphological changes of the trachea with an electron-microscope. Observations on its functional aspects were also made by estimation of the ciliary movement per minute. The present study has revealed a considerable damaging effect of styrene on the tracheal mucosa, which we presented in this report in the hope that it could be used as an index in settling the maximum permissible concentration of styrene for the future.

Animals↗
PubMed1982

[Experimental studies on the acute toxicity of tetrahydrofuran in animals].

The toxicity of tetrahydrofuran (THF), an important solvent in chemical industries, was studied by experiments on mice and rats. Acute toxicity was studied by intraperitoneally injecting 20% THF solution in various doses and by causing THF of various concentrations to be inhaled. Toxic symptoms appearing during the experimental period were observed. The results are as follows: 1. Acute toxic dose of THF. LD50 was estimated to be 2,500 mg/kg in mice with intraperitoneal administration of 20% THF-olive oil solution and 1,900 mg/kg in mice and 2,900 mg/kg in rats with intraperitoneal administration of 20% THF-0.9% NaCl solution. LC50 was estimated to be 21,000 ppm in rats when THF was inhaled for three hours. 2. Acute toxicity by inhalation of THF for three ours. Rats exposed to 100 to 200 ppm of THF showed no significant effects, except for slight local irritant symptoms such as redness of the nose and eyelids. Almost all rats exposed to over 5,000 ppm of THF displayed marked local irritant symptoms such as edema or opacity of the cornea, salivation and discharge or bleeding in nasal mucosa. A cataleptoid posture, coma and clonic muscle spasms indicating irritant symptoms of the central nervous system were also observed.

Animals↗
PubMed1982

[Experimental studies on the toxicity of tetrahydrofuran administered to animals by repeated inhalation].

The toxicity of tetrahydrofuran (THF) was evaluated by repeated inhalation experiments on rats. The animals were separated into a control group and groups exposed to 100, 200, 1,000 or 5,000 ppm THF for 4 hours a day, 5 days a week over a 12-week period. No significant differences appeared between the groups exposed to 100 ppm as well as 200 ppm and the control group, except for slight local irritant symptoms of the mucosa. The group exposed to 1,000 ppm showed an effect on the liver function according to the results by serum chemistry test. In the group exposed to 5,000 ppm, marked local irritant symptoms and morphological damage of the respiratory mucous membrane were found upon histological examinations. Also significant differences were noted between this group and the control group in white blood cell counts, blood sugar values and liver functions by hematological and serum chemistry tests.

Administration, Intranasal↗
PubMed1981

[Studies on industrial styrene poisoning (part XII). Electron-microscopic observations on the mucosal membrane of respiratory tracts of rats exposed to styrene. (author's transl)].

The influences which are known to be caused by styrene on the human body are stimulation of the mucosal membrane and atrophy of the central nervous system. There are several clinical reports and animal experiments concerning the stimulation of the mucosal membrane, and styrene is presumed to stimulate the mucosal membrane of the nose. To the best of our knowledge, however, there have been no reports describing histological pathology of the mucosal membrane of the nose induced by exposure to styrene. Accordingly we made animal experiments using rats in order to see influences of styrene on the mucosal membrane of the upper and lower respiratory tracts including the mucosal membrane of the nose, and could confirm the following changes electron-microscopically: 1. Increases in the amount of mucous adhering to cilia, 2. Occasional formation of compound cilia, 3. Appearance of substances having a higher electron-microscopic density within the cytoplasm of various epithelial cells, 4. Degeneration of secretory granules of goblet cells--changes in electron-microscopic density, appearance of cores with a higher electron-microscopic density, 5. Nuclear pyknosis, 6. Vacuolization of various epithelial cells, and 7. Separation and falling-off of the epithelial cell layer.

Animals↗
PubMed1981

Distribution, elimination and retention of styrene in rats.

In rats exposed to styrene for 4 hours, the rate constant of elimination and biological half life of styrene were 0.11 and about 6 hours for adipose tissue, and 0.3 to 0.4 and about 2 hours for the other tissues, respectively. The relative ratio of apparent distribution of styrene decreased in the order adipose tissue much greater than liver greater than brain greater than kidney greater than blood not equal to spleen greater than muscle. Almost the same results were obtained in the experiment by intraperitoneal injection of styrene. Repeated 4-hour exposures at about 700 ppm daily for five days caused the results similar to those in a single exposure. A trend of increase in concentration of styrene was observed in adipose tissue by 5 successive intraperitoneal injections every 6 hours at a dose of 350 mg/kg.

Animals↗
PubMed1980

Studies of maternal and fetal 11-deoxycorticosterone, corticosterone,18-hydroxycorticosterone and aldosterone in normal and toxemic pregnancy.

Simultaneous determination of maternal and fetal plasma 11-deoxycorticosterone (DOC), corticosterone (B), 18-hydroxycorticosterone (18OH-B) and aldosterone (ALDO) in normal and toxemic pregnancies was performed by utilizing a newly developed radioimmunoassay. The mean levels of plasma DOC and ALDO in normal term pregnancy were significantly higher than those of nonpregnant women. Comparing the mean levels of umbilical arterial plasma to those in maternal plasma at delivery, DOC and ALDO were consistently higher in the former, while B was higher in the latter, and 18OH-B was largely unchanged. However, no umbilical arteriovenous gradient was found in any corticosteroid measured. In toxemia of pregnancy, the corticosteroid levels in the maternal plasma were lower than those in normal pregnancies, and in umbilical arterial plasma, B was significantly higher and 18OH-B and ALDO remained almost the same as those in normal pregnancy. Thus, it appears that ALDO synthesis in mother in normal term pregnancy was enhanced but in toxemia of pregnancy it was suppressed, while in the fetus, it was enhanced not only in normal pregnancy but also in toxemia of pregnancy.

18-Hydroxycorticosterone↗
PubMed1980

[Studies on the industrial styrene poisoning (Part X). Determination of styrene in biological materials by gas chromatography (author's transl)].

For monitoring solvents exposure, it is useful to determine not only metabolites of the solvents in urine but also the solvents themselves in blood and tissues. In a series of studies on the industrial styrene poisoning, we have been determining styrene in blood and other tissues as occasion calls. Our examination of the method is presented in this report. The outline on the method is as follows: Aliquots of 0.5g of tissues being added 5 ml of n-hexane are homogenized by a high-speed homogenizer (Polytoron) for 10 to 30 seconds and the filtrates containing extracts are analyzed for styrene by gas chromatography. The linearity was ascertained from the calibration curve obtained by adding the known quantities of styrene (4, 10, 20, 40, 100 ppm) to the blood, liver and adipose tissues of rats. Rates of recoveries of styrene from the above tissues were 92 to 101 per cent. Reproducibility of this method was examined by repeating determinations of styrene in the blood, liver and adipose tissues of rats exposed to 500 ppm styrene for 4 hours, the coefficients of variation being 2.8 to 14.0 per cent. There was an approximately linear relationship between the styrene concentration (0 to 1,000 ppm) of the exposed air and those in the blood of exposed rats. We conclude that our simple and rapid method is applicable to determination of solvents other than styrene in organs and tissues by combining suitable solvents for extraction and packings of gas chromatography.

Animals↗