Koichi Fukumoto

Studies on osmotic fragility of red blood cells determined with a coil planet centrifuge for workers occupationally exposed to lead.

SummaryIn order to clarify the relationship between lead exposure level and osmotic fragility of red blood cells determined by the coil planet centrifuge method, several clinical laboratory examinations were performed on 27 male workers employed in a scrap lead refining factory using as controls 40 male workers employed in railway construction. The examinations included measurement of red blood cell and reticulocyte counts, hematocrit, MCV, blood and urine lead concentrations, urine coproporphyrin, and urine δ-aminolevulinic acid. The results were:1.Osmotic fragility of red blood cells was lower in lead workers at all three hemolytic points compared with the controls. Significant difference was observed in hemolysis of the maximum point (P < 0.05).2.The red blood cell and reticulocyte counts, hematocrit value and MCV of the lead workers were not significantly different from those of the controls. Values for blood and urine lead, coproporphyrin, and δ-aminolevulinic acid of the lead workers were much higher than those of the controls (P < 0.01).3.In lead workers, close relationships between the osmotic fragility and these laboratory findings were observed: blood lead, r=-0.572, P<0.01; coproporphyrin, r= −0.608, P<0.01; δ-aminolevulinic acid, r= −0.559, P< 0.01; urine lead, r = −0.453, P < 0.05.

Alterations of lipids of the erythrocyte membranes in workers exposed to lead

SummaryChanges in lipids (cholesterol and phospholipids) of the erythrocyte membrane were studied and several laboratory examinations were performed with 25 male workers employed in a scrap lead refining factory using as controls 38 male railway construction workers. The examinations included measurements of erythrocyte count, hematocrit, mean corpuscular volume (MCV), blood and urine lead concentrations, urine coproporphyrin and δ-aminolevulinic acid, membrane cholesterol (CHO) and phospholipids (PL), total and free CHO in plasma, and lecithin cholesterol acyltransferase (LCAT) activity in plasma. The results were:1)Membrane CHO (P < 0.01) and CHO: PL ratio (P < 0.05) of lead workers were higher than those of the controls. But no significant difference was observed in membrane PL between both groups.2)Membrane phosphatidyl choline was higher (P < 0.05) and lysophosphatidyl choline was lower (P < 0.05) in lead workers compared with controls. But no significant difference was observed in membrane sphingomyelin, phosphatidyl serine, and phosphatidyl ethanolamine between both groups.3)Free CHO in plasma was higher (P < 0.05) in lead workers compared with controls. But no significant difference was observed in total CHO in plasma, erythrocyte count, hematocrit, MCV, and LCAT activity between both groups.

Cellulose acetate electrophoretic determination of bone alkaline phosphatase activity in healthy subjects and diabetic patients with and without osteopenia

We adapted the electrophoretic method of bone alkaline phosphatase (ALP) determination using neuraminidase from Vibrio cholerae to separate bone and liver ALP on cellulose acetate membrane. Treatment of separator plus serum (1:8, neuraminidase 111 U/l in final) for 10 min at room temperature (25 +/- 1 degree C) and subsequent electrophoresis made it possible to quantify bone ALP activity simply and rapidly. The precision of the data was at the level of CV of 1.6% (within-day) and 4.7% (day-to-day), with recovery rates of 97-103%. The normal range of bone ALP activity depended on age and sex. Seventy-eight diabetes mellitus (DM) patients, excluding those with renal failure, were divided into two groups of those with and without osteopenia with matching of age (+/- 3 years) and sex. Bone ALP (P < 0.001) and total ALP (P < 0.05) activities and urine calcium/creatinine ratio (P < 0.05) were significantly higher in DM with osteopenia than in DM without osteopenia. Therefore, bone formation and absorption may be accelerated in DM with osteopenia in comparison with DM without osteopenia.

Analysis of guanase by agarose gel electrophoresis and activity staining.

A method was developed to separate guanase by agarose gel electrophoresis and to detect its activity by staining of the bands with a mixture of the enzymes xanthine oxidase, catalase, and aldehyde dehydrogenase, the coenzyme NADP+, and a substrate of guanine, ethanol, phenazine methosulfate, nitrotetrazolium blue, and KCN in Tris-(hydroxymethyl)methylamine buffer (pH 8.0). Serum samples showed bands 1 (faster moving) and 2 corresponding to the positions of albumin and alpha 2-globulin, respectively, found by serum protein staining. The same bands were detected with guanase from human liver and kidney, although band 2 from the latter samples was not as distinct as that from the liver samples.

Epidemiological study of occupational exposure to hepatitis B virus and liver function tests

A total of 1020 hospital employees were divided into an exposure group (n = 725) and a non-exposure group (n = 295), based on whether they had been exposed to blood from patients. The HBsAg-positive rates for the exposure and the non-exposure groups were 2.48% and 1.02%, respectively. In the exposure group, the minimal exposure rate increased with age from the twenties. The odds ratios were 7.39 in the technicians, 4.38 in physicians and 1.32 in nurses. Using age-sex matched pairs from the exposure and non-exposure groups, comparison of aspartate aminotransferase, alanine amino-transferase and guanase activities showed that there were significantly higher values in HBsAg-positive subjects (n = 18) from the exposure group than in HBsAg- and HBsAb-negative subjects from the non-exposure group (p less than 0.05-0.01). However, no significant differences were found in the enzyme activities in the matched pairs (n = 89) of HBsAb-positive subjects from the exposure and non-exposure groups.

Combined effects of lead and edta on Na+,K+‐ATPase activity of erythrocyte membranes

Erythrocyte Na+,K+-ATPase activity increased significantly in lead workers of a lead refining factory when measured with EDTA and compared to the controls without EDTA. The enzyme activity measured with EDTA increased in the following order: controls less than office workers in a lead refining factory less than lead workers. A positive correlation existed between blood lead and enzyme activity with EDTA (r = 0.380, p less than 0.10), and the activity without EDTA (r = 0.398, p less than 0.05). A negative correlation was found between sodium in erythrocytes and enzyme activity with EDTA (r = -0.437, p less than 0.05), and the activity without EDTA (r = -0.416). But no relationship was observed between enzyme activities and potassium in erythrocytes. A positive correlation between enzyme activity with EDTA and that without EDTA was observed (r = 0.452, p less than 0.05). With addition of lead to fragments of erythrocyte membranes, a significant decrease occurred in the activity of the enzyme without EDTA, whereas no change was observed with EDTA. No significant change occurred in the enzyme activity with and without EDTA upon addition of lead to blood. The maximum level of lead in membrane fragments (lead combined with membranes) of workers exposed to lead was 0.60 microgram/mg protein, and that in the experiment of addition to blood was 7.0 micrograms/mg protein.