PubMed Health⌕ Search

Biomedical subjects

Y Tasaki

Publications and source records attributed to Y Tasaki.

47 records · Page 3Linked to original sources
PubMed1990

Activation of branched-chain alpha-keto acid dehydrogenase complex by exercise: effect of high-fat diet intake.

The effect of exercise on the activity of branched-chain alpha-keto acid dehydrogenase complex in liver and muscle was studied in rats fed a high-fat (FAT) or a high-carbohydrate (CHO) diet. Both diet groups of rats were offered isoenergetic diets by a meal-feeding method and were trained by treadmill running. On the final day of the experiment, half of the rats in each diet group were exercised by 2 h of running just before they were killed. The activity state of the enzyme complex was elevated maximally by exercise in liver of rats fed the FAT diet but not in liver of rats fed the CHO diet, suggesting that catabolism of branched-chain amino acids in rat liver during exercise was enhanced by the FAT diet. The activity state of the enzyme complex in muscle was enhanced by exercise in both groups of rats, but a significant difference was not observed between the groups. The concentration of branched-chain amino acids was elevated in liver and muscle by exercise in both groups of rats, but the elevated levels in liver were lower in rats fed the FAT diet than in those fed the CHO diet. Serum branched-chain amino acid concentrations were significantly lower in rested rats fed the FAT diet than in those fed the CHO diet, and the leucine and isoleucine concentrations in the former were elevated by exercise, but the serum concentrations in the latter were not significantly affected by exercise. ATP and ADP concentrations in muscle were not significantly affected by either diet or exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗
PubMed1986

Annual cycle of plasma thyroid hormone levels in the toad, Bufo japonicus.

Plasma thyroxine (T4) of the toad, Bufo japonicus formosus, was monitored monthly from March, 1981 to February, 1982. Toads were captured at Sayama, Saitama Prefecture, and individual blood samples were collected from the heart soon after capture in the field. The plasma T4 levels were minimal in November for males (0.096 ng/ml) and in December for females (0.038 ng/ml). Levels increased during the resting stage in winter and reached a peak in March, about 1 week before the breeding migration, in both males (0.48 ng/ml) and females (0.66 ng/ml). After breeding occurred in early April, the T4 levels fell rapidly to nearly the minimum in females (0.088 ng/ml) and to an intermediate level in males (0.26 ng/ml). During summer, the T4 levels were low (between 0.1 and 0.3 ng/ml) but were significantly higher than the minimum in both sexes. Males showed significantly higher T4 levels than females in January, April, October, and December. Changes in plasma T4 levels around the breeding period were studied in greater detail with toads collected in March at Shiki, Saitama Prefecture. Extremely high levels of T4 (1.72 ng/ml) were detected in both male and female toads collected in the breeding pond, showing a secondary rise of the T4 level at arrival at the breeding pond. Plasma triiodothyronine (T3) levels followed patterns similar to those of T4, although the concentrations of T3 were extremely low (between undetectable level and 116 pg/ml). The initial rise of the thyroid hormone level in winter may be related to energy metabolism at the low temperature.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Hemispheric lateralization of spatial contrast sensitivity.

Visuospatial contrast sensitivity was determined by the Arden grating chart in 23 patients with cerebral infarctions involving the primary visual cortex or visual association cortex. Subjects were classified into three groups according to their lesions: I, 6 patients with unilateral medial occipital or occipitotemporal lesions; II, 6 patients with left lateral parieto-occipital lesions; and III, 11 patients with right lateral parieto-occipital lesions. Contrast sensitivity was markedly reduced in Group III, especially in patients having hemispatial agnosia. Group I patients with hemispatial agnosia showed almost normal contrast sensitivity. Spatial contrast sensitivity appears to be more affected when the lesion has an influence on the nondominant lateral parieto-occipital cortex.

Adult↗
PubMed1979

[Thermal behavior of gypsum bonded investments. (Part I) Thermal behavior in heating process(author's transl)].

The cause of the three shrinkages in the thermal expansion curves of gypsum bonded investments, which were characterized in the previous study, was examined mainly by means of TG-DTA method, X-ray diffraction method and SEM observation. The main results were as follows: 1. The first shrinkage between 100 degrees C and 200 degrees C was caused by the dehydration of gypsum. 2. The second shrinkage between 300 degrees C and 400 degrees C was due to the transformation of soluble anhydrite to insoluble anhydrite. 3. The third shrinkage beginning at the temperature range 700 degrees C approximately 800 degrees C is considered to be related to the sintering of insoluble anhydrite.

Anhydrides↗
PubMed1979

[Thermal behavior of gypsum bonded investments. (Part 2) Sintering phenomena of set plaster (author's transl)].

The sintering phenomena of set plaster on the heating process have been investigated by measuring shrinkage and apparent density and by observing the structure of fractured surface with SEM. As a result, it was found that the sintering shrinkage occurred in two stages for the temperature range from 500 degrees C to 900 degrees C. In the first stage between 500 degrees C and 800 degrees C, the skelton of needle-like crystals of gypsum remained and micro-grains were observed in it. In the second stage between 800 degrees C and 900 C, the skelton disappeared and the grain growth was remarkable. In addition, the rate of shrinkage was slow in the first stage, and was very fast in the second stage.

Calcium Sulfate↗
PubMed1979

[Thermal behavior of gypsum bonded investments. (Part 3) Sintering kinetics of insoluble anhydrite (author's transl)].

The sintering kinetics of insoluble anhydrite were studied by measuring the isothermal shrinkage of compacts of insoluble anhydrite powders in air. The sintering process of insoluble anhydrite powders consisted of two stages for the temperature range from 630 degrees C to 720 degrees C. The first shrinkage could be described as a bulk diffusion model and followed the equation delta L/Lo infinity t 0.5l +/- 0.08, where delta L/Lo is fractional shrinkage and t is the sintering time. The apparent activation energy of the shringage was 130 kcal/mole. The second shrinkage followed the equation delta L/Lo infinity t 1.83 +/- 0.30, but could not be explained with reasonable model. However, the SEM observations of the fractured surface of compacts suggested that the second shrinkage corresponded to the grain growth of insoluble anhydrite.

Anhydrides↗
PubMed1978

[Dilatometry of gypsum bonded investment (author's transl)].

Although many investigations on the thermal expansion of dental investments have already been done, the conditions upon which thermal expansion was measured were not always definitely shown and the phenomena on thermal behavior of dental investments were not reasonably interpreted. In this investigation the effects of W/P ratio of samples, heating rate and furnace atmosphere were studied by "Push Rod" Dilatometer in order to attempt to standardise dilatometry of dental investments. All experiments were designed with two-way layout techniques. The main results were as follows, 1) W/P ratio, heating rate and furnace atmosphere have significant effects on the thermal expansion curves of the gypsum bonded investments. 2) One steep expansion and three stages of shrinkage in heating process of these investments from room temperature to about 900 degrees C were observed. 3) The quantity of the steep expansion, first and second stages of shrinkage and the expansion at 650 degrees C were affected by W/P ratio. 4) The temperature at which the steep expansion or shrinkage occurred were affected by heating rate. 5) Furnace atmosphere affected on both quantity of the steep expansion or shrinkage and their temperature. It also affected on the expansion at 650 degrees C. Then, these factors should be considered in dilatometry of gypsum bonded investments and in dental practice.

Calcium↗