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Biomedical subjects

H Aikawa

Publications and source records attributed to H Aikawa.

At least 127 records · Page 7Linked to original sources
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

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↗
PubMed1981

Hemorrhage of thiamine-deficient encephalopathy.

Hemorrhagic lesions of pyrithiamine-induced acute thiamine-deficient encephalopathy of the mouse (PIATDEM) consisted of petechiae, which often coalesced to form small hematomas. Electron microscopy showed the typical petechial lesion to be composed of a perivascular necrotic zone containing fibrin-platelet clot surrounded by a ring of erythrocytes. Endothelial cells were intact and tight junctions were closed. A study of permeability to horseradish peroxidase (HRP) revealed only a slight increase in the number of transport vesicles in the endothelial cells. A large amount of HRP present in the lesions seemed to have entered the brain by a hemorrhagic route which remains unclarified. Spherical latex particles, 0.23 micrometer in diameter, were injected intravenously into encephalopathic mice at a time when intracerebral hemorrhages frequently occurred. Two to 24 hours after the injection, a large number of latex particles penetrated the blood vessels at sites of hemorrhage. There were many particles in the phagosomes of the endothelial cells, which suggested transendothelial transport by the organelle. The possibility of endothelial phagocytic transport of erythrocytes as a main route of diapedesis is discussed.

Animals↗
PubMed1980

Effects of concentration and duration of toluene exposure on Sidman avoidance in rats.

Fifteen rats in which responding under the Sidman avoidance schedule had been established were first exposed to air for 4 hr, then randomly to 350, 750 or 1,500 ppm of toluene vapor for 1, 2 or 4 hr, following which the effects on lever pressing behavior were investigated for 80 min after the termination of toluene exposure. The effect of concentration, exposure duration and test period on lever pressing of toluene was revealed clearly in the test. Using the technique adopted in this experiment, one could be determining the minimal effective exposure condition in terms of toluene concentration and exposure duration is 1,500 ppm for 2 hr. These findings suggest the usefulness of this technique in assessing the behavioral toxicity of toluene.

Analysis of Variance↗
PubMed1979

[An experimental study of nursing work load on the low back (author's transl)].

The relation between work postures and muscle load, the differences of muscle load in holding two different shaped objects, a human model and a box each weighting 20 kg, and the effects of wearing a belt and a corset to reduce the low back muscle load were studied in the experimental nursing work on physically and/or mentally handicapped patients. Four female healthy college students exercised a static and a dynamic nursing work designed for the experiment. E.M.G., heart rate, subjective symptoms and maximum sustaining time were measured during the work. Results are as follows: 1) The low back muscle load increased only in sustaining the forward bending posture. 2) The forward bending posture with a load weighing 20 kg caused shortening of the time to sustain the same posture. 3) The muscle load by holding the human model was larger compared to that by holding the box, and the muscle load was different according to the shape of the holding objects. 4) Wearing a belt and a corset was effective to reduce the low back muscle load by raising the abdominal pressure.

Adult↗
PubMed1979

[Evaluation of toluene toxicity using Sidman avoidance behavior by lever pressing in rats (author's transl)].

Effects of single exposure to toluene on the operant behavior in rats were studied. The animals, in which the behavioral base line had been established, were exposed to 0, 1,000 and 3,000 ppm of toluene vapor for four hours, and the effects on the behavioral pattern of lever pressing were investigated for one hour after the end of exposure using Sidman avoidance test. 1) Exposure to 0 or 1,000 ppm of toluene did not affect the established operant behavior of the rats. 2) Exposure to 3,000 ppm produced increased responses, shortening of the inter-response-time, and no change in shock counts at the early stage of Sidman avoidance test when compared with those before exposure. 3) The behavioral change indicated here appears to be caused by a temporary breakdown of the established timing of lever pressing. 4) The effect of toluene on the operant behavior was strongest immediately after the aviodance test begun and the behavior recovered in about an hour. From the results of our experiment it can be said that the experimental methods used in this study is useful to evaluate the toxicity of toluene to the central nervous system of the animals.

Animals↗
PubMed1978

Effect of single exposure to toluene on Sidman avoidance response in rats.

Effects of single exposure to toluene on Sidman avoidance response in rats were studied. The animals, in which the behavioral base line had been established, were exposed 0, 1,000 and 3,000 ppm of toluene vapor for 4 hours and the effects on the behavioral pattern were investigated using Sidman avoidance test for one hour after the termination of toluene exposure. 1) Exposure to 0 or 1,000 ppm of toluene did not produce marked change on the operant behavior. After the exposure to 3,000 ppm, the animals produced increased responses with shortening of the inter-response-time (IRT) and no changes in shock counts from the beginning to the 50 min. zone of the Sidman avoidance test when compared with those before exposure. The behavioral change indicated here appears to be caused by a temporary breakdown of the established timing of lever pressing. 2) The effect of toluene on the operant behavior was strongest immediately after the termination of the exposure and the behavior recovered in about an hour. This result suggested that toluene is rapidly transfered to and removed from the brain.

Animals↗