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Biomedical subjects

I Uehara

Publications and source records attributed to I Uehara.

14 recordsLinked to original sources
PubMed2001

YCu3Al2, an example of an AB5 structure type.

Yttrium tricopper dialuminium, YCu(3)Al(2), is isostructural with hexagonal CaCu(5), in which each Cu atom at the 3g((1/2),0,(1/2)) position in space group P6/mmm (No. 191) is partially replaced by an Al atom. The hydrogen-uptake properties are usually enhanced in other AB(5) structures by aluminium substitution. YCu(5) does not show any hydrogen absorption, and the goal of the present work is to investigate whether aluminium substitution could expand the metal-atom lattice enough to provide better interstitial positions for hydrogen storage. However, no enthalpy change was observed up to 773 K under 3 MPa static H(2) pressure by differential thermal analysis (DTA) for the title compound. The compound does not show any significant hydrogen absorption/desorption in the pressure-composition isotherms (P-C-T diagrams) in the temperature range 298-673 K under 3.3 MPa H(2) pressure.

Journal Article↗
PubMed2000

Differences in episodic memory between four- and five-year-olds: false information versus real experiences.

It is assumed that personal episodes from any age less than about four years can rarely be recalled (infantile amnesia) because episodic memory is not well developed until this age. To investigate this, experiments were conducted with 30 4- and 30 5-yr.-olds. Experiments first examined whether the children could report parent-child games in a sports festival two days after the festival. The results indicated that 4-yr.-olds could not report the episodic contents of the games properly even though they reported the results of the ball matches as well as the 5-yr.-olds. Seven days after that report, the subject was told twice by the experimenter about realistic or unrealistic events as if these were their own experiences. The subject was again required to report the events seven days after receiving information. The results showed that 4-yr.-olds tended to mistake the information provided by the experimenter for their own real experiences. These results indicate that there may be a critical difference of episodic memory between 4- and 5-yr.-olds. Episodic memory was not well developed yet in 4-yr.-olds.

Age Factors↗
PubMed2000

Transition from novelty to familiarity preference depending on recognition performance by 4-yr.-olds.

Preference seems to depend exclusively on individual tastes; however, preferential behavior may be determined by memory, as past studies have shown that preferences for objects depended on whether objects had been previously experienced. Infants and young children prefer novel stimuli, while adults prefer familiar stimuli. To investigate the relationship between memory and preference directly, a preference task and a recognition task were administered to the same subjects. The subjects were 4-yr.-olds because Uehara observed a change in preference for novelty and familiarity in 4-yr.-olds, depending on their recognition performance. The results were similar to those of Uehara. The children who had lower scores in the recognition task preferred the novel stimuli in the preference task, and the children who had higher scores preferred the familiar. Developmental changes within children, from low scores on recognition coupled with novelty preference to high scores on recognition coupled with familiarity preference, were observed.

Adult↗
PubMed1999

Differences in recognition and preference among four- and five-year-olds on a tactile learning and visual test.

Infants' preferential looking at novel objects and adults' preference for the familiar indicate that preference may be influenced by whether the objects have been experienced previously. Infants and adults may have opposite preferential tendencies; however, infants' preference for a familiar object which they have experienced orally casts doubt on this as a developmental process. To examine both the influences of experienced modalities and age on the relationship between preference and memory, tactile-visual preference and memory tests were employed in 4- and 5-yr.-olds. The results indicated the dissociation of preference by recognition only in 4-yr.-olds: those who recognized the objects preferred the familiar and the 4-yr.-olds who could not recognize them preferred the novel. The 5-yr.-olds tended to prefer the familiar objects regardless of recognition. The results may suggest an age effect on the relationship between preference and recognition.

Child↗
PubMed1998

No transfer of visuomotor learning of button-pressing from right to left hands in right-handed four-year-olds.

To assess the underlying mechanism of visuomotor learning in children and its relation to the cerebral lateralization, intermanual transfer of learning was examined on a button-press task. The main experiment examined transfer of learning from one hand to the other for 36 right-handed 4-yr.-olds, 19 5-yr.-olds, and 8 adults. The experiment consisted of three phases. In the first and second of three phases, the subject performed the task with the right [(or left) hand, then with the left (or right)]. All age groups exhibited transfer from the left to the right hands; however, the 4-yr.-olds showed no transfer from the right to the left, whereas the other age groups showed transfer from the right to the left as well as left to right. Results were discussed in relation to the underlying mechanism of learning and hemispheric organization, and a new interpretation was proposed.

Adult↗
PubMed1984

Effects of zinc and copper content of formulas on growth and on the concentration of zinc and copper in serum and hair.

We studied the effect of dietary zinc (Zn) and copper (Cu) on the levels of these elements in serum (at 1, 3, and 5 months of age) and in hair (at 5 months of age) of breast- and formula-fed infants. Three different formulas were used: (a) Commercially available standard infant formula containing 1.0 mg/L of Zn and 30 micrograms/L of Cu; (b) Zn supplemented formula, containing 3.2 mg/L of Zn and 30 micrograms/L of Cu; and (c) Zn- and Cu-supplemented formula, containing 3.2 mg/L of Zn and 400 micrograms/L of Cu. The median Zn content of breast milk was 4.8 mg/L at 1 week, 2.9 mg/L at 1 month, 1.1 mg/L at 3 months and 1.1 mg/L at 5 months. Breast milk Cu content was 510 micrograms/L at 1 week, 440 micrograms/L at 1 month, 270 micrograms/L at 3 months, and 200 micrograms/L at 5 months after delivery. All infants were healthy and full term, and weight and length velocities were similar in each of the four groups studied. Serum Zn levels were significantly higher both in the infants fed the Zn-supplemented formula and those fed the Zn-and-Cu-supplemented formula compared with the other two groups of infants at 3 and 5 months of age. Zn levels in hair were significantly elevated (invariably greater than 80 micrograms/g) only in infants fed Zn-supplemented formula.(ABSTRACT TRUNCATED AT 250 WORDS)

Body Height↗
PubMed1983

Four-hydroxyphenylpyruvic acid oxidase deficiency with normal fumarylacetoacetase: a new variant form of hereditary hypertyrosinemia.

Enzymatic studies on the liver of an infant are described-a case of hypertyrosinemia without hepatic dysfunction. His parents were siblings and the mother had hypertyrosinemia. Excessive amounts of 4-hydroxyphenylpyruvic acid (pHPP), 4-hydroxyphenylacetic acid (pHPL), and 4-hydroxyphenylacetic acid (pHPA) were found to be excreted in the patient's urine as well as in the urine of the mother and the inhibitor of porphobilinogen synthetase was not found. Soluble tyrosine aminotransferase (s-TAT), separated from that of the mitochondrial form (m-TAT) by DE 52 column chromatography, was normal in the patient's liver, both quantitatively and qualitatively. The activities of fumarylacetoacetase in the patient's liver and in the peripheral leucocytes from the parents were normal. The activity of pHPP oxidase in the patient's liver was approximately 5% of the control and the enzyme had a high Km value for pHPP (controls: 0.06 +/- 0.01 mM, patient: 0.23 +/- 0.03 mM). From these results, the patient was thought to be different from previously described types of tyrosinemia and perhaps representative of a new variant form. This is the first report concerning 4-hydroxyphenylpyruvic acid oxidase deficiency alone. Mild metal retardation and mild hypertyrosinemia may be offered as typical clinical features of the disease.

4-Hydroxyphenylpyruvate Dioxygenase↗
PubMed1982

Skin histidase activity and urine formiminoglutamic acid (FIGLU) in patients with histidinemia found by screening newborn infants.

Skin histidase activities and urine formiminoglutamic acid (FIGLU) levels were measured in 20 patients with histidinemia, identified by Guthrie's screening method, and their family members as well as control subjects. There was a significant positive correlation between skin histidase activities and the amounts of urine FIGLU. Although the difference of skin histidase activity and the amount of urinary FIGLU was significant between any two of the three groups (i.e. controls, parents and patients; p less than 0.005), these levels ranged widely and a considerable number of the cases overlapped among groups. When a discriminant function was computed to obtain the minimum probability of misclassification between the groups using the above two parameters, a better segregation was observed. However, even though the number of misclassifications decreased, the overlapping cases were still present, especially between the parent and patient groups. It is concluded that either skin histidase activity, urine FIGLU, or both, can be used as genetic markers of the disease to a large but still limited extent.

Amino Acid Metabolism, Inborn Errors↗
PubMed1982

Effect of low-content zinc and copper formula on infant nutrition.

The zinc (Zn) content of commercially available formula milks in Japan is less than that of breast milk obtained during the first three months of lactation, but is similar to that at five months of lactation. The copper (Cu) content of the formula milks is much lower than that of breast milk obtained during the five months. These two trace elements were measured in serum (at birth, one, three, and five months of age), hair (at birth and at five months of age) and urine (at one, three and five months of age) of twenty-one breast fed and twenty formula fed full term infants. Despite the differences in Zn and Cu intakes, these parameters were similar in these two infant groups, except for urinary Zn at one and three months of age. These were significantly higher in breast fed infants (P less than 0.005 and P less than 0.05). Weight and length increments were not different in either infant group. It appeared that normal, full term infants tolerated low-content Zn and Cu formula milks well. This observation, however, is not at variance with the FAO/WHO recommendation for prevention of Zn and Cu deficiency.

Age Factors↗
PubMed1982

Zinc and copper contents in breast milk of Japanese women.

Longitudinal studies of zinc and copper contents of breast milk were performed in 65 Japanese mothers during their lactation period until 5 months postpartum. They experienced no problems during pregnancy and at delivery. All women had full term healthy infants. Forty-five were multiparous and 20 primiparous. The highest level of zinc content was found in the colostrum, and subsequently the levels declined (p less than 0.005), as lactation progressed. Copper content was stable during the first month of lactation, and then declined gradually (p less than 0.005). Both mineral levels in breast milk ranged with great variance among the subjects at any stages of lactation. Significantly lower zinc level (p less than 0.01) and higher copper level (p less than 0.005) were found in the serum of lactating women three months postpartum, when compared with non-lactating control women. Factors including lactation history, age of lactating women, serum levels and contents of zinc and copper in the hair did not affect the contents of these trace minerals in the breast milk.

Colostrum↗