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.

Guanine deaminase in serum as an indicator of survival probability in severe shock patients

To find ways of predicting survival or death in cases of severe shock, arterial blood pH and gases, vital signs, and the half-life of activity in the enzymes guanine deaminase, aspartate aminotransferase (AST) and alanine aminotransferase (ALT), were studied in 24 patients. The mean arterial blood pH (+/- SD) in survivors was 7.325 +/- 0.092 while that in non-survivors was 7.108 +/- 0.251 (p less than 0.05). The mean half-life of guanine deaminase in survivors was 19.8 +/- 3.3 hours, while that in non-survivors was 58.6 +/- 11.8 hours (p less than 0.001). When the screening values were set at 7.190 for the arterial blood pH and 36 hours for the half-life of guanine deaminase activity, the 'validity' (sensitivity plus specificity) for the combination of the two tests was 1.88. The values may be useful for the prognosis of survival in severe shock patients.

Effect of lead on erythrocyte membranes

The effect of blood lead on erythrocyte membrane proteins was studied in 28 workers from a scrap lead refining factory and in 18 controls working in railway construction. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of the polypeptides in the erythrocyte membrane showed that bands 3 and 4.1 had significantly decreased while bands 2.3, 6, and 7 had significantly increased in the lead workers compared with the controls. For the lead workers, the correlation coefficients between blood lead and bands 2.3 and 3 were r = 0.545 (p less than 0.01) and r = -0.51 (p less than 0.01) respectively. These results suggest that the decrease in erythrocyte membrane permeability results from a decrease in the membrane transfer protein responsible for band 3.

Erythrocyte arginase activity as an indicator of lead exposure

ABSTRACT A semi-automated method has been developed for the determination of the arginase activity of erythrocytes using dried blood spots, which are easy to prepare on site in a factory for later laboratory analysis. The mean arginase activity of erythrocytes in 49 men occupationally exposed to lead was 62·9 IU/g·Hb (SD, 14·4 IU/g·Hb); in 45 men not exposed to lead the mean was 44·6 IU/g·Hb (SD, 11·6 IU/g·Hb). A significantly higher mean arginase activity was found in the specimens from lead-exposed workers (p < 0·001). The correlation coefficient between blood lead and erythrocyte arginase was r = 0·67 (p < 0·001). The degree of correlation between blood lead and lead indicators including arginase was r = 0·75 for urine δ-aminolaevulinic acid, r = 0·67 for erythrocyte arginase, r = 0·66 for urine lead, and r = 0·63 for coproporphyrin. Erythrocyte arginase showed no significant correlation in the liver function tests, GOT, GPT, and albumin in serum. When 40 μg/100 g of blood lead concentration was fixed as the basic value and 56·2 IU/g·Hb of erythrocyte arginase activity was set as the screening value in lead-exposed workers, the sensitivity and specificity of the arginase test were 0·96 and 0·65, respectively. Thus the validity of the test was calculated to be 1·61. These results show that the arginase level of erythrocytes can be considered to be one of the significant indicators of occupational exposure to lead because it reflects well the dose-response relationship of lead in the human body. Our method allows rapid analysis of erythrocyte arginase and thus should be useful in screening for lead exposure.

[Effects of lead on the protein of erythrocyte membranes]

In order to study the effects of lead in the circulating peripheral blood on the erythrocyte membrane, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of protein in the erythrocyte membrane was performed in 28 men exposed to lead in a scrap lead refining factory and 18 men working in railway construction as the controls. Furthermore, in order to corroborate the effects in vitro experiments by SDS-PAGE of protein in the mixture of human erythrocyte membranes with added lead were performed. 1) In the lead workers compared with the controls, SDS-PAGE of protein in the erythrocyte membrane showed that relative concentrations of bands 1, 2, 3 and 4.1 were significantly decreased while those of bands 2.3, 6 and 7 were significantly increased. 2) SDS-PAGE of protein in the in vitro experiment showed that the relative concentrations of bands 1, 2, 3, 4.1 and 4.2 were decreased while those of bands 2.3, 4.5, 5, 6 and 7 were increased. Therefore, these results show the same trends as those of the in vivo experiments. 3) For the lead workers, the correlation coefficients between blood lead and bands 2, 2.3 and 3 were r = -0.414 (p less than 0.05), r = 0.545 (p less than 0.01) and r = -0.509 (p less than 0.01), respectively. Also a higher coefficient of correlation (r = -0.777, p less than 0.001) was found between bands 2 and 2.3. 4) As the molecular weight of substances showing bands 2 and 2.3 were 220700 and 133800, respectively, according to PAGE using molecular weight markers, band 2.3 is considered to be due to a cleavage product from that of band 2. From these results, we summarized as follows. Lead combined with erythrocyte membrane decreases the band 3 penetrating lipid bilayer, and that causes the decrease of membrane transportation. On the other hand, the variation of band 2 and 4.1 influences the spectrin-actin network. This is considered to be one of the reasons that MCV is decreased.

Effect of lead in vitro on water metabolism and osmotic fragility of human erythrocytes

The addition of lead to normal human blood was previously found to cause a decrease in erythrocyte osmotic fragility in vitro. The mechanism of the decreased osmotic fragility caused by lead has not been completely clarified, but the following hypothesis has been proposed. Lead causes a leakage of water from erythrocytes, thus more water can enter the cell before haemolysis occurs. There has been no report, however, of the direct measurement of the intracellular water content of erythrocytes treated with lead. This study has tried to clarify the relation between intracellular water and the osmotic fragility of lead-treated erythrocytes in vitro. The results showed that 0.05 microM/ml of lead decreased the osmotic fragility, the intracellular water content, and intracellular potassium and mean corpuscular volume, increased the plasma water content and trapped water content, and contracted the erythrocyte shape. These changes corresponded well with each other, and close coincidence of the osmotic fragility and the intracellular water content was also observed.

An increase in the Na+/K+-ATPase activity of erythrocyte membranes in workers employed in a lead refining factory

To clarify the relationship between erythrocyte Na+/K+-ATPase activity and haematological findings, several clinical laboratory examinations were performed on 31 male workers employed in a scrap lead refining factory and, as controls, 50 male workers employed in railway construction. The results were: (1) Values for erythrocyte Na+/K+-ATPase activity, blood and urine lead, urine delta-aminolaevulinic acid, and urine coproporphyrin of lead workers were significantly higher than those of the controls (p less than 0.01). (2) A strongly positive relationship between blood lead and erythrocyte Na/K-ATPase activity was observed in lead workers (r = 0.473, p less than 0.01). (3) A strongly negative relationship between Na+/K+-ATPase activity and intracellular sodium was observed in both groups (lead workers; r = -0.601, p less than 0.01: controls; r = 0.595, p less than 0.01).

Mechanism of increased osmotic resistance of red cells in workers exposed to lead

In order to clarify the mechanism of the increased osmotic resistance of red blood cells in lead workers 19 men employed in a lead refining factory and 18 control male workers employed in railway construction were examined for red cell count, haematocrit, MCV, blood and urine lead concentrations, urine coproporphyrin and delta-aminolevulinic acid, osmotic resistance of red cells, lecithin-cholesterol acyltransferase (LCAT) activity in serum, and cholesterol content and cholesterol-to-phospholipid ratio of the red cell membrane. The results were: (1) The osmotic resistance of the red cells (p less than 0.05), cholesterol content of the red cell membrane, blood and urine lead, urine coproporphyrin, and urine delta-ALA concentrations (p less than 0.01) were higher in the lead workers than in the controls. (2) In the lead workers close relationships were observed between the osmotic resistance and the blood lead concentration (r = -0.515, p less than 0.05), osmotic resistance and LCAT activity (r = 0.596, p less than 0.01), and osmotic resistance and cholesterol of the red cell membrane (r = -0.492, p less than 0.05).

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

Changes 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 delta-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 less than 0.01) and CHO: PL ratio (P less than 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 less than 0.05) and lysophosphatidyl choline was lower (P less than 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 less than 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.

Relationships between osmotic fragility of red blood cells and various hematologic data in workers exposed to lead

This paper describes relationships between osmotic fragility (OF) of red blood cells and various hematologic data in 32 male workers exposed to lead and 30 controls. The examination included measurements of OF determined by the coil planet centrifuge system, red blood cell (RBC) count, hematocrit, hemoglobin, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), water of RBC, sodium and potassium of RBC, blood and urine lead, urine coproporphyrin, and urine delta-aminolevulinic acid. The results were: 1) OF was lower in lead workers at all three hemolytic points compared with the controls (P less than 0.05). 2) A difference in hemolysis pattern between the two groups was observed (P less than 0.05). 3) A close relationship was observed in both groups between OF and MCV (P less than 0.05), although the results were contrasting. Also a close relationship was observed in lead workers between OF and hematocrit, OF and hemoglobin, OF and MCH, and OF and intracellular potassium (P less than 0.05) but not in the controls. In the controls a close relationship was found between OF and RBC (P less than 0.05) but this was not observed in the lead workers. No significant relationship was observed in either group between OF and MCHC, OF and intracellular sodium, and OF and intracellular water. 4) No difference in RBC, hematocrit, hemoglobin, MCV, MCH, MCHC, and intracellular water, sodium and potassium was observed between both groups.

Improvement in the atomic absorption determination of lead in blood

A simple, precise and accurate analysis for lead in blood and tissue was developed using spectrophotometry after extraction with HCl, H3PO4, KI and methyl isobutyl ketone. The results were similar to those obtained by anodic stripping voltammetry. The method is simple, requires only four reagents, does not need pH adjustment for lead extraction, saves time and is suitable for analyzing a large number of specimens.

Treatment of ulcerative colitis by the direct administration of an antifibrinolytic agent as an enema

Fibrinolytic activity in biopsied colonic mucosa was examined in patients with ulcerative colitis, and most cases were found to have increased tissue fibrinolysis -- due mainly to tissue plasminogen activator -- in the affected mucosa. Five cases, 4 with elevated tissue fibrinolysis and 1 normal, were treated with an antifibrinolytic agent, tranexamic acid (trans-AMCHA) administered as an enema, to inhibit fibrinolysis of the affected mucosa directly. In patients with elevated mucosal fibrinolysis, 2 showed complete remission after tranexamic acid enema alone, and there was one remission in response to combination treatment with oral prednisolone. One case with slightly elevated mucosal fibrinolysis showed clinical improvement, although the radiological findings were unchanged. No response was observed in one case with normal tissue fibrinolysis. It is concluded that tranexamic acid may show a therapeutic effect in ulcerative colitis with elevated mucosal fibrinolysis when administered via an enema, which allows direct contact of the drug with the affected mucosa.

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

In 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 delta-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 less than 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 delta-aminolevulinic acid of the lead workers were much higher than those of the controls (P less than 0.01). 3. In lead workers, close relationships between the osmotic fragility and these laboratory findings were observed: blood lead, r = -0.572, P less than 0.01; coproporphyrin, r = -0.608, P less than 0.01; delta-aminolevulinic acid, r = -0.559, P less than 0.01; urine lead, r = -0.453, P less than 0.05.

[The effect of lead on intracellular water content of human red blood cells. Part 1. An experiment in vitro (author's transl)]

We observed in vitro experiment that lead increased osmotic resistance of normal human erythrocytes and decreased mean corpuscular volume and intracellular potassium. Though the mechanism of the increased osmotic resistance of erythrocytes caused by lead has not yet been completely clarified, the following hypothesis could be accepted. Lead causes leakage of water from erythrocytes, which means that more water can enter the cell before hemolysis occurs. But there has been no report of direct measurement of the intracellular water content of erythrocytes treated with lead. This paper tried to clarify the relationship between intracellular water and osmotic resistance of lead treated erythrocytes in vitro experiment. The results were: 0.05 mumol/ml of lead increases osmotic resistance, trapped water content and plasma water content of normal human blood and decreases intracellular water content after incubation for 2 hours at 37 degrees C.

Kinetic measurement of guanine deaminase in serum with a centrifugal analyzer

We describe an enzymic, one-step kinetic method for determination of guanine deaminase (guanase, EC 3.5.4.3) in serum with a centrifugal analyzer. A combined enzyme-substrate system consists of the enzymes xanthine oxidase, catalase, and aldehyde dehydrogenase, the coenzyme NAD+, the substrate guanine, and ethanol in tris(hydroxymethyl)methylamine buffer, with KCl added as activator for aldehyde dehydrogenase. The method requires only 40 microL of sample. Guanase activity in 28 samples can be determined within 10 min by setting a 4-min lag period. The increase in absorbance at 340 nm is linearly proportional to the activity of guanase to 60 U/L. Within-run precision (CV) was 1.32 to 4.50% over the range studied. Day-to-day precision corresponds to CVs of 4.8 to 7.2% over the same range of guanase activity. The reference interval, as calculated from data on 25 healthy humans, was 0 to 1.02 U/L. The enzymic automated method shows good correlation with Caraway's (Clin. Chem. 12: 187, 1966) method (r = 0.949).

Kinetic measurement of guanine deaminase in serum with a centrifugal analyzer

We describe an enzymic, one-step kinetic method for determination of guanine deaminase (guanase, EC 3.5.4.3) in serum with a centrifugal analyzer. A combined enzyme-substrate system consists of the enzymes xanthine oxidase, catalase, and aldehyde dehydrogenase, the coenzyme NAD+, the substrate guanine, and ethanol in tris(hydroxymethyl)methylamine buffer, with KCl added as activator for aldehyde dehydrogenase. The method requires only 40 microL of sample. Guanase activity in 28 samples can be determined within 10 min by setting a 4-min lag period. The increase in absorbance at 340 nm is linearly proportional to the activity of guanase to 60 U/L. Within-run precision (CV) was 1.32 to 4.50% over the range studied. Day-to-day precision corresponds to CVs of 4.8 to 7.2% over the same range of guanase activity. The reference interval, as calculated from data on 25 healthy humans, was 0 to 1.02 U/L. The enzymic automated method shows good correlation with Caraway's (Clin. Chem. 12: 187, 1966) method (r = 0.949).