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K Tomokuni

Publications and source records attributed to K Tomokuni.

At least 91 records · Page 5Linked to original sources
PubMed1980

[Normal levels of delta-aminolevulinic acid in the spot urines of adult men, as measured by a simplified method (author's transl)].

Increased urinary excretion of delta-aminolevulinic acid (ALA) is an early biological sign of toxic lead absorption. Therefore, its determination is a very useful screening test for the periodical examination of workers exposed to lead. Previously, we developed a simplified method for determining urinary ALA without ion-exchange column. This method is based on two findings: (a) ALA-pyrrole is extractable with ethyl acetate to be separated from other Ehrlich-positive substances such as urea, and (b) the ALA-pyrrole can form a complex with the modified Ehrlich's reagent in ethyl acetate. In the present study, using this method, we determined urinary ALA of healthy adult men and estimated the normal levels for ALA. The results are as follows: (1) The urinary ALA concentration obtained from the spot urine samples of 299 workers (age: mean=37.1 years range=20-56 years) with no history of occupational lead exposure was 2.39 +/- 0.87 mg/liter (mean and standard deviation), with upper limit of 4.10 mg/liter for 95%-confidence interval. (2) The distribution of ALA in the normal spot urine was not log-normal, but normal. (3) No significant difference between the excretion level of urinary ALA and the age was observed.

Adult↗
PubMed1979

The in vitro effect of metal ions on the activity of erythrocyte delta-aminolevulinic acid dehydratase.

The effects of a total of 15 metals on the activity of erythrocyte delta-aminolevulinic acid dehydratase (ALA-D) were investigated in vitro. The degree of inhibition of the ALA-D activity by copper, tin, mercury and silver was almost equal to that by lead, when the metal was added to the hemolysate of whole blood at the concentrations of 0.1 to 1.0 mmol/l in the ALA-D assay. Magnesium, manganese and beryllium had no effect on the ALA-D activity at the same concentrations. Zinc had a mild activating effect on ALA-D at the optimum concentrations and it eliminated the inhibitory effect of lead to some extent. However, the inhibitory effects of both mercury and cadmium on ALA-D were not quite eliminated even by the addition of zinc. These facts seem to suggest that the inhibition mechanism of lead on ALA-D differs from those of other metals.

Adult↗
PubMed1979

Interaction of zinc and other metal on the activity of erythrocyte delta-aminolevulinic acid dehydratase in vitro.

The interaction of zinc and other metal such as lead, mercury (II), cadmium, silver (II) on the activity of erythrocyte delta-aminolevulinic acid dehydratase (ALA-D) was investigated in vitro. At the concentrations ranging from 0.01 to 1.0 mmol/l, lead, mercury (II), cadmium and silver (II) strikingly inhibited the erythrocyte ALA-D activity. The in vitro addition of zinc having an activating effect for the erythrocyte ALA-D, was observed to eliminate the lead-induced inhibition of the erythrocyte ALA-D activity. And the degree of the elimination seemed to depend on the molar ratio (Zn/Pb) of both metal concentrations in the ALA-D assay. However, the inhibition of erythrocyte ALA-D activity caused by mercury (II), cadmium and silver (II) was not removed by the in vitro addition of zinc.

Cadmium↗
PubMed1976

Relationship between lead concentration in blood and biological response for porphyrin metabolism in workers occupationally exposed to lead.

The biological responses of the heme biosynthesis pathway in male workers moderately exposed to lead are discussed in relation to the concentration of lead in the blood. The level of erythrocyte delta-aminolevulinic acid dehydratase (ALA-D) activity in the group of lead-exposed workers was remarkably reduced while the level of erythrocyte protoporphyrin (Proto) in them was strikingly increased, compared to normal levels. On the other hand, the amounts of hemoglobin (Hb) and urinary delta-aminolevulinic acid (ALA) in the group of lead-exposed workers kept the normal levels. In the workers moderately exposed to lead, the log of erythrocyte Proto level was closely correlated to the blood lead level and the sensitivity of the Proto test was almost equal to that of erythrocyte ALA-D test. It was observed that the erythrocyte Proto was remarkably increased even in lead-exposed workers whose ALA excretion into the urine was in the range of normal level.

Aminolevulinic Acid↗
PubMed1975

Relationship between activation of delta-aminolevulinic acid dehydratase by heating and blood lead level.

Both blood lead and erythrocyte delta-aminolevulinic acid dehydratase (ALA-D) activity were determined for workers with and without an occupational lead exposure. In workers occupationally exposed to lead, it was demonstrated that the erythrocyte ALA-D is markedly activated by heating the hemolysate at 60 degrees C for 5 min and there is a good positive correlation between the ratio of heated to nonheated ALA-D activity and the blood lead level (r=0.799). In addition, by heating the hemolsyate, the ALA-D activity of the lead-exposed workers appears to be returned into the normal range regardless of the extent of lead absorption. However, in normal workers without the occupational lead exposure, no significant correlation was found between the ratio of heated to nonheated ALA-D activity and the blood head level, although the normal ALA-D also can be slightly activated by heating the hemolysate at 60 degrees C for 5 min.

Environmental Exposure↗
PubMed1975

Different behaviors of erythrocyte delta-aminolevulinic acid dehydratase. A comparison study between lead workers and normals.

Different characteristics of erythrocyte delta-aminolevulinic acid dehydratase (ALA-D1) between the workers with the history of occupational lead exposure and normals are described. In the blood of lead workers, when the hemolysates are heated at 60 C for five minutes, the activity of the erythrocytes ALA-D increases up to about 3.6-fold of an initial level, and as a result of heating the optimum in pH-activity curvee changes from pH 6.0 to pH 6.6, which is similar to the optimum pH of normal ALA-D. On the contrary, in normal blood, the optimum in the pH-activity curve is but little changed, even though the erythrocyte ALA-D activity is increased up to about 1.3-fold of the initial level by heating the hemolysates at 60 C for five minutes.

Adult↗
PubMed1975

Erythrocyte protoporphyrin test for occupational lead exposure.

Determination of erythrocyte protoporphyrin levels was performed in workers who are occupationally exposed to lead. The level of erythrocyte protoporphyrin was easily measured with microsamples of blood by utilizing a fluorescent assay. The log of erythrocyte protoporphyrin level was closely correlated to blood lead level (r = .72) in lead-exposed workers. The erythrocyte protoporphyrin test is especially useful in the detection of mild increases in blood lead concentration under conditions of occupational exposure.

Alcohol Drinking↗