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Biomedical subjects

T Misawa

Publications and source records attributed to T Misawa.

At least 127 records · Page 7Linked to original sources
PubMed1986

Strain difference in learning impairment in rats following lead administration during brain development.

High and stable avoidance with low variability (THA) rats and non-select Wistar rats were administered 2 mg/ml lead acetate solution (0.2-0.27 g/Kg/day as lead) up to seven weeks of age; via placenta from the 13th day of gestation and from maternal milk before weaning, and per os after weaning. Results were as follows. 1) Significant differences were not observed between the lead-exposed rats and the controls regarding the developmental landmarks in both the Wistar rats and THA rats. Body weight of the exposed rats, however, were significantly less than that of the controls of the two rat strains. 2) Low rate of avoidance, slow acquisition of learning and large individual variabilities were exhibited in both the controls and the exposed rats of the Wistar strain throughout the test sessions. No significant difference was indicated between the controls and the exposed rats of the Wistar strain. In the control THA rats, avoidance learning was acquired rapidly, and a high level and very small individual variabilities of avoidance were demonstrated during the latter sessions of the test. Meanwhile, in the exposed THA rats, slow learning acquisition and large individual variabilities were displayed. It is thought that the learning impairment appearing in the THA exposed rats was induced primarily by lead.

Animals↗
PubMed1985

Effect of somatostatin and its analogs on histamine-stimulated cAMP production in isolated guinea pig gastric glands.

The effect of somatostatin-14 (ss-14), somatostatin-28 (ss-28), and [D-trp8]somatostatin-14 ([ D-trp8]ss-14) on both histamine-stimulated cellular cAMP production and [3H]-cimetidine binding on plasma membranes in isolated guinea pig gastric glands was investigated. These three peptides partially inhibited (approximately 50% maximally) the increase of cAMP production stimulated by histamine. There was no inhibition of [3H]-cimetidine binding on plasma membranes from these isolated gastric glands. These results indicate that somatostatin acts directly on parietal cells and inhibits histamine-stimulated cAMP production with no influence on H2 receptor in histamine stimulated gastric secretion. Inhibitory potency of somatostatin and its analogs against histamine-stimulation may be equal at the cellular level.

1-Methyl-3-isobutylxanthine↗
PubMed1984

The air crescent sign of invasive pulmonary mucormycosis in acute leukemia.

An unusual radiographic sign of crescentic cavitation appeared in a case of invasive pulmonary mucormycosis complicating the treatment of a patient with acute myelogenous leukemia and having a normal admission chest radiograph. The first manifestation was a large, wedge-shaped pleural-based consolidation, which evolved about 10 days later into a fungus ball-like lesion, usually known as the air crescent sign. Amphotericin B and 5-fluorocytosine, which were initiated immediately after appearance of the sign, proved to be effective, probably in association with hematologic improvement. Transbronchial lung biopsy was not only helpful in establishing a definitive diagnosis, but also suggested that an intracavitary mass could have resulted from pulmonary infarction. This experience thus showed that the sign may appear in greater frequency in mucormycosis as well as in aspergillosis, and may be useful as a clinical index for initiating antifungal therapy in immunocompromised patients.

Adult↗
PubMed1984

[An experimental study on the duration of a single spell of work on VDT (visual display terminal) performance].

The relation between work load and the duration of a single spell of work on VDT performance studied in an experimental word processing task. Nine healthy male college students performed 2-hour visual tasks under the following three sets of work conditions. In the first set, subjects performed VDT work for two hours without intermission. In the second set, subjects had a 10-minute intermission after a 1-hour task. In the third set, there was a 5-minute intermission after a 30-minute task. Critical flicker fusion, near point distance, subjective fatigue symptoms, heart rate, respiratory rate, blinking counts, electromyogram in upper limb and performance score were measured. Results are as follows. Decrease in critical flicker fusion, increase in near point distance and subjective fatigue symptoms appeared in all three sets of experimental conditions after two hour tasks. Increased slow wave components on electromyogram and increased errors in performance appeared after 60-minute or more tasks without intermission. Effects on the critical flicker fusion, near point distance, subjective fatigue symptoms, electromyogram, blinking counts and errors in performance were least in the third set. The results of this study suggest that in order to reduce operators' fatigue on VDT work of the conversation type, countermeasures such as shortening the duration of a single spell of work to less than 60 minutes and taking frequent short intermission are necessary.

Adult↗
PubMed1983

[Effects of alcohol drinking on mental task performance].

The effects of low level alcohol in man were studied by several psychophysiological tests. Five male college students were tested on the battery of mental tasks involving Dot-Matrix, Signal Sound Detection, Choiced Reaction Time at three levels (33.5, 67.0, 134.0 ml : whisky) of alcohol dose. Alcohol concentration in breath, critical flicker fusion, heart rate and blinking counts were measured. Results obtained are as follows. Increase in the alcohol concentrations in breath and heart rate, decrease in the blinking counts are shown in proportion to alcohol dose level. Alcohol effects of least dose (33.5 ml) in this experiment are shown clearly on the condition of adding two subsidiary tasks to the main task. The results of this study suggest that the complex-task-method is useful to estimate the effects of low level alcohol to the psychophysiological functions in man.

Adult↗
PubMed1982

Effect of cimetidine o endocrine functions--prolactin.

Effects of cimetidine on the endocrine function were examined in 16 human subjects, i.e. 6 healthy adult volunteers, and each 5 male and female gastro-duodenal ulcer patients. They were all subjected to the examination on the fluctuation of prolactin (PRL) after one-shot intravenous injection of cimetidine. The peptic ulcer patients were orally given 800 mg/day of cimetidine for further 4 weeks. PRL, gonadotropins and sex hormones were determined in the male patients, and only PRL in the females patients. TRH-load test was carried out in all the ulcer patients before and after the administration of cimetidine. The results are shown below: 1) After one-shot intravenous administration of cimetidine 200 mg, serum-PRL significantly increased, the peak level, however, being within normal value range. The increase in PRL was transient, and recovered to the pretreatment value in 60-180 minutes after the administration. 2) During and after the repeated oral administration of 800 mg/day of cimetidine for the consecutive 28 days, serum PRL level did not significantly change. Neither was noted any influence on gonadotropin (LH, FSH) nor sex hormones (estradiol, testosterone) secretion. 3) PRL secretory functions at 500 microgram TRH loading were similar before and after oral administration of cimetidine, without difference in the reactivity.

Adult↗
PubMed1982

Effects of maternal exposure to toluene during pregnancy on mouse embryos and fetuses.

Female mice 11 weeks of age (ICR Strain) with vaginal plugs were divided into three groups. Two groups were exposed to 100 or 1,000 ppm of toluene and the other group was exposed to air in the exposure chamber of six hours every day from the 1st to 17th day of gestation. On the 18th day of gestation, two thirds of the mice in each group were sacrificed and their uteri were examined from implantation and resorption sites. The fetuses were weighed and external examinations for malformations were performed. Skeletal preparations stained with alizarin red S were also examined. To compare the postnatal growth of pups in the three groups, the rest of the mice in each group were delivered. Results were as follows. 1. Incidence of resorbed fetuses in the 100ppm and 1,000ppm toluene exposed groups was increased when compared with the control group, but the difference was not statistically significant. 2. No significant difference was observed in the number of implantation sites, mean live or dead fetuses and mean fetal body weight among the three groups. 3. External malformations were found at a low frequency, and no difference was seen among the three groups. 4. Body weight gains, and periods of eye or ear-opening, weaning, full incidence of body hair and coordinated walking of pups showed no differences among the groups. 5. Incidence of skeletal abnormalities was low, except for extra 14th ribs and rudimentary 14th ribs. The high incidence of extra 14th ribs in the 1,000ppm toluene exposed group suggested the possible teratogenicity of toluene.

Abnormalities, Drug-Induced↗