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).     

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).     

铅作业人员的尿粪卟啉和血细胞参数的测定意义

目的:探讨金属铅对铅作业人员血液系统的影响,及尿粪卟啉和血细胞参数测定的意义。方法:以铅作业工人465人为观察组,以不接触铅和其他生产性毒物的某单位职工286人为对照组,各取尿20 ml和EDTA-K2抗凝血2 ml,用荧光比色法进行尿粪卟啉测定,用CA-900全自动血液分析仪进行血细胞分析。结果:铅作业组的尿粪卟啉阳性率42.5%明显高于对照组2.10%(χ2=146.7,P<0.01),血红蛋白与红细胞降低检出率(8.17%4、.73%)高于对照组的(1.75%、1.04%)(P<0.01,P<0.05)。结论:金属铅对铅作业人员的血液系统的影响,主要表现为卟啉代谢紊乱和血红素合成障碍,要定期对铅作业人员测定尿粪卟啉和血细胞参数,及早发现铅中毒人员,维护铅作业人员的身体健康。     

Changes of membrane fluidity in erythrocytes of lead-exposed workers

Summary We have studied the effect of lead on the fluidity of erythrocyte membrane to clarify if lead can interact in vivo with biological membranes. Erythrocyte membranes were chosen in our study because a decrease of red cell osmotic fragility is also evident in the absence of laboratory and clinical signs of anaemia. The study was undertaken using the Electron Spin Resonance technique with two spin labels 5-doxyl stearate and 16-doxyl-stearate, which probe the physical state of the polar surface and the inner core of the membrane respectively.Red blood cells and erythrocyte ghosts were prepared from the blood of workers occupationally exposed to lead and from healthy controls. The determinations of Pb blood, Pb urine, urine coproporphyrin and -amino levulinic acid showed an increased internal dose of lead, but the ordinary metabolic and haematological parameters were in the normal range. Our results show that in lead workers there is a change in chemical physical state both in erythrocytes and erythrocyte ghosts consistent with a decrease of membrane fluidity, which is evident in the surface as well as in the inner core of the membrane. The degree of membrane fluidity modification does not appear correlated with blood lead level. Changes in the membrane structural organization could be the molecular basis of some pathological alterations induced by lead.     

Role of lipids in stabilizing red cells in rats

The causes of osmotic fragility of red cells were studied in rats. Osmotic fragility of red cells in vivo changed after removal of the spleen or induction of experimental splenomegaly by repeated intraperitoneal injections of methyl cellulose (MC): in splenectomized rats, the red cells showed reduced osmotic fragility and an increase in diameter as well as in contents of phospholipids and cholesterol. Conversely in rats with splenomegaly, the cells showed increased osmotic fragility and a decrease in diameter and in lipid contents. Results confirmed that increase in the phospholipid content resulted in decreased fragility and that increase in the cholesterol content brought about decreased spherocytosis. The activity of lecithin cholesterol acyltransferase (LCAT) in the plasma varied inversely with the cholesterol content of the red cells. The above results show that the fragility of red cells is influenced by their lipid content and shape, and that LCAT activity in the plasma influences the membrane content of cholesterol and spherocytosis.     

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.     

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.     

Correlation between some parameters of lead absorption and lead intoxication

Waldron, H. A. (1971).Brit. J. industr. Med.,28, 195-199. Correlation between some parameters of lead absorption and lead intoxication. Use has been made of data collected over a number of years from workers exposed to a lead hazard in a motor-car factory. The correlations between various parameters of lead absorption and lead intoxication were computed, including blood and urine lead concentrations, urinary coproporphyrin, ALA and PBG concentrations, and haemoglobin concentration. In all, 15 correlation coefficients were calculated, of which only six showed a statistically significant result (i.e., P<0·05). These six were blood lead and urine lead (r = 0·38, P<0·001), urine lead and coproporphyrin (r = 0·42, P<0·001), urine lead and ALA (r = 0·43, P<0·001), coproporphyrin and ALA (r = 0·75, P<0·001), ALA and PBG (r = 0·49, P<0·001), and urine lead and PBG (r = 0·19, P<0·05).     

铅中毒筛选指标的再评价

目的 评价铅中毒筛选指标的准确性。方法 连续收集１５７名铅接触工人的血标本,同时测定血铅,红细胞游离原卟啉（ＦＥＰ）,锌卟啉（ＺＰＰ）,尿铅,尿δ－氨基－酮戊酸（δ－ＡＬＡ）,红细胞嘧啶５′核苷酸酶（Ｐ５′Ｎ）的活性。以血铅≥１．９３μｍｏｌ／Ｌ,≥２．９０μｍｏｌ／Ｌ为金标准,用受试工作特征（ＲＯＣ）,曲线下的面积评价上述指标在血铅≥１．９３μｍｏｌ／Ｌ,≥２．９０μｍｏｌ／Ｌ的准确性,用ＲＯ     

Familial aggregation of red blood cell cation transport systems in Japanese families

The rate of lithium, sodium, and potassium transport in red blood cells is thought to be associated with essential hypertension. In order to investigate the contribution of genetic and environmental factors to cation transport, their correlation was analyzed in 60 parent-offspring pairs and 17 husband-wife pairs in Toyama City, Japan. Lithium-sodium countertransport and sodium-potassium cotransport rates were significantly correlated in parent-offspring pairs (r = 0.52, p less than 0.01 and r = 0.46, p less than 0.01, respectively) but not in husband-wife pairs. Sodium pump rates were significantly correlated in both pairs (r = 0.48, p less than 0.01 in parent-offspring pairs, r = 0.46, p less than 0.05 in husband-wife pairs). Therefore, lithium-sodium countertransport and sodium-potassium cotransport were found to have a substantial genetic component and the sodium pump to have a substantial environmental component. Sodium pump rates were significantly correlated with sodium/creatinine (r = 0.21, p less than 0.05) and sodium/potassium (r = 0.32, p less than 0.01) in casual urine.     

In vivo tibia lead measurements as an index of cumulative exposure in occupationally exposed subjects

In vivo tibia lead measurements of 20 non-occupationally exposed and 190 occupationally exposed people drawn from three factories were made using a non-invasive x ray fluorescence technique in which characteristic x rays from lead are excited by gamma rays from a cadmium-109 source. The maximum skin dose to a small region of the shin was 0.45 mSv. The relation between tibia lead and blood lead was weak in workers from one factory (r = 0.11, p greater than 0.6) and among the non-occupationally exposed subjects (r = 0.07, p greater than 0.7); however, a stronger relation was observed in the other two factories (r = 0.45, p less than 0.0001 and r = 0.53, p less than 0.0001). Correlation coefficients between tibia lead and duration of employment were consistently higher at all three factories respectively (r = 0.86, p less than 0.0001; r = 0.61, p less than 0.0001; r = 0.80, p less than 0.0001). A strong relation was observed between tibia lead and a simple, time integrated, blood lead index among workers from the two factories from which blood lead histories were available. The regression equation from two groups of workers (n = 88, 79) did not significantly differ despite different exposure conditions. The correlation coefficient for the combined data set (n = 167) was 0.84 (p less than 0.0001). This shows clearly that tibia lead, measured in vivo by x-ray fluorescence, provides a good indicator of long term exposure to lead as assessed by a cumulative blood lead index.     

In vivo tibia lead measurements as an index of cumulative exposure in occupationally exposed subjects.

In vivo tibia lead measurements of 20 non-occupationally exposed and 190 occupationally exposed people drawn from three factories were made using a non-invasive x ray fluorescence technique in which characteristic x rays from lead are excited by gamma rays from a cadmium-109 source. The maximum skin dose to a small region of the shin was 0.45 mSv. The relation between tibia lead and blood lead was weak in workers from one factory (r = 0.11, p greater than 0.6) and among the non-occupationally exposed subjects (r = 0.07, p greater than 0.7); however, a stronger relation was observed in the other two factories (r = 0.45, p less than 0.0001 and r = 0.53, p less than 0.0001). Correlation coefficients between tibia lead and duration of employment were consistently higher at all three factories respectively (r = 0.86, p less than 0.0001; r = 0.61, p less than 0.0001; r = 0.80, p less than 0.0001). A strong relation was observed between tibia lead and a simple, time integrated, blood lead index among workers from the two factories from which blood lead histories were available. The regression equation from two groups of workers (n = 88, 79) did not significantly differ despite different exposure conditions. The correlation coefficient for the combined data set (n = 167) was 0.84 (p less than 0.0001). This shows clearly that tibia lead, measured in vivo by x-ray fluorescence, provides a good indicator of long term exposure to lead as assessed by a cumulative blood lead index.     

铅作业工人血铅、尿铅和锌原卟啉测定结果分析

目的比较铅作业工人和非铅作业工人血铅、尿铅浓度、红细胞锌原卟啉和血常规的差异,探讨铅作业工人红细胞锌原卟啉和血铅、尿铅浓度的相关性。方法以蓄电池企业的252名铅作业工人作为接铅组,电子厂205名非铅作业工人作为对照组,测定血铅、尿铅浓度、红细胞锌原卟啉和血常规,并对结果进行统计学处理。结果接铅组血红蛋白含量低于对照组(P0.05),白细胞和红细胞、血小板则无差异(P0.05),接铅组红细胞锌原卟啉、血铅、尿铅浓度均显著高于对照组(P0.01),尿铅与红细胞锌原卟啉的相关系数(r)=0.166,血铅与红细胞锌原卟啉的相关系数r=0.406。结论长期接触铅可导致血铅、尿铅浓度和红细胞锌原卟啉升高,血红蛋白降低,对白细胞、红细胞、血小板无明显影响,血铅与红细胞锌原卟啉的相关性较尿铅与红细胞锌原卟啉的相关性好。     

Erythrocyte deformability in workers exposed to lead.

Erythrocyte deformability and other hematological indicators were determined in 17 male workers exposed to lead at a secondary lead refinery and 13 controls. Blood lead, urine lead, urine coproporphyrin, delta-aminolevulinic acid and erythrocyte zinc protoporphyrin were determined to evaluate the degree of lead exposure in the lead workers above. For the measurement of erythrocyte deformability, the microfilter method was used. The results were summarized as follows: 1. The mean values of blood lead, urine lead, urine coproporphyrin, urine delta-aminolevulinic acid and erythrocyte zinc protoporphyrin levels in lead workers were 53.5 micrograms/100g, 141.4 micrograms/l, 115.9 micrograms/l, 12.0 mg/l and 68.9 micrograms/dl respectively, suggesting a moderate influence of lead exposure. 2. The mean values of erythrocyte count, hematocrit and hemoglobin were significantly lower in lead workers than those in controls. No significant differences were found in the mean values of mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration and corpuscular natrium and potassium between lead workers and controls. 3. Erythrocyte deformability was significantly reduced in lead workers compared with controls.     

Erythrocyte membrane microviscosity and phospholipid composition in lead workers

The microviscosity and fluidity of erythrocyte ghost membranes from lead workers and control subjects was measured by fluorescence polarisation using the fluorophore, 1,6-diphenyl-1,3,5-hexatriene (DPH). Increased lead was associated with a significant decrease in the average microviscosity of resealed and unsealed erythrocyte membranes. Since DPH fluorescence reflects the organisation of lipids in the central core of the membrane, two aspects of phospholipid metabolism were investigated. Phospholipids were extracted from red blood cell ghost membranes and identified by high performance liquid chromatography. The ratio of phosphatidyl choline to phosphatidyl ethanolamine, an established correlate of membrane fluidity, was significantly increased in lead workers. This is attributed to the known increases in red blood cell cholesterol in lead workers and the structural incompatibility of phosphatidyl ethanolamine and cholesterol, which result in a compensatory increase of phosphatidyl choline. Erythrocyte ghost membranes from control subjects were resealed with the intermediates in phospholipid synthesis that increase with a lead inhibited decrease in red blood cell pyrimidine 5'-nucleotidase. Membrane fluidity was not modified by incubation with cytidine triphosphate, uridine triphosphate, cytidine diphosphate choline, or cytidine diphosphate ethanolamine. Alterations in the microviscosity of the lipid regions of the hydrophobic core of the erythrocyte membrane bilayer and in the phospholipid composition of the membrane may be defects which contribute to the clinical and biochemical instability of the red blood cell on exposure to lead.     

Erythrocyte membrane microviscosity and phospholipid composition in lead workers.

The microviscosity and fluidity of erythrocyte ghost membranes from lead workers and control subjects was measured by fluorescence polarisation using the fluorophore, 1,6-diphenyl-1,3,5-hexatriene (DPH). Increased lead was associated with a significant decrease in the average microviscosity of resealed and unsealed erythrocyte membranes. Since DPH fluorescence reflects the organisation of lipids in the central core of the membrane, two aspects of phospholipid metabolism were investigated. Phospholipids were extracted from red blood cell ghost membranes and identified by high performance liquid chromatography. The ratio of phosphatidyl choline to phosphatidyl ethanolamine, an established correlate of membrane fluidity, was significantly increased in lead workers. This is attributed to the known increases in red blood cell cholesterol in lead workers and the structural incompatibility of phosphatidyl ethanolamine and cholesterol, which result in a compensatory increase of phosphatidyl choline. Erythrocyte ghost membranes from control subjects were resealed with the intermediates in phospholipid synthesis that increase with a lead inhibited decrease in red blood cell pyrimidine 5'-nucleotidase. Membrane fluidity was not modified by incubation with cytidine triphosphate, uridine triphosphate, cytidine diphosphate choline, or cytidine diphosphate ethanolamine. Alterations in the microviscosity of the lipid regions of the hydrophobic core of the erythrocyte membrane bilayer and in the phospholipid composition of the membrane may be defects which contribute to the clinical and biochemical instability of the red blood cell on exposure to lead.     

An assessment of the laboratory tests used to monitor the exposure of lead workers

Hæger-Aronsen, Birgitta (1971). Brit. J. industr. Med., 28, 52-58. An assessment of the laboratory tests used to monitor the exposure of lead workers. In order to ascertain which laboratory tests are valuable for the monitoring of lead workers, 168 men exposed to lead at eight factories were examined for lead (Pb), protoporphyrin (PP), haemoglobin (Hb), and basophilic stippling of red cells (BSC) in the blood and for δ-aminolevulinic acid (ALA) and coproporphyrin (CP) in the urine.

The counting of BSC and the determination of PP in the blood are both complicated and time-consuming procedures. As they do not offer any particular advantages in the detection or evaluation of lead poisoning they are considered as less suitable.

The concentration of Pb in the blood reflects the absorption of the lead but not its effect. This is certainly a disadvantage.

A highly significant, negative correlation was found between Hb in the blood and ALA in the urine.

The concentrations of ALA and CP in the urine are both good indicators of the degree of lead poisoning. The former is more specific and more sensitive and is therefore considered the most suitable test for the biochemical monitoring of lead workers. A simple, safe, and quick method is recommended.

Determinations of Hb and Pb in the blood may be useful as supplementary methods in the evaluation of lead poisoning but are, in our experience, only seldom needed.

     

某蓄电池厂作业工人血铅、尿铅与指甲铅检测结果分析

目的 通过对某蓄电池厂工作人员血铅、尿铅及指甲铅水平的分析, 探讨三者在职业病诊断中的价值。
方法 留取该企业203名作业工人静脉血标本、尿标本以及指甲标本, 用石墨炉原子吸收光谱法测定血铅、尿铅以及指甲铅水平, 并对数据进行统计学分析。
结果 该企业铅烟时间加权平均浓度(C_TWA)为(0.31 ±0.37) mg/m3, 铅尘C_TWA为(0.28 ±0.50) mg/m3。员工血铅均值为(280.37 ±164.86)μg/L, 异常率为22.7%;尿铅均值为(0.035 ±0.042) mg/L, 异常率为11.3%;指甲铅均值为(1 407.96 ±2 625.26)μg/g。男性工人血铅、尿铅、指甲铅水平均高于女性工人, 差异有统计学意义(P < 0.01或0.05)。不同工龄组工人血铅、尿铅异常率差异均无统计学意义(P>0.05)。血铅、尿铅水平和指甲铅水平均存在相关关系(r=0.544、0.546, P < 0.01)。
结论 该蓄电池厂铅作业工人血铅、尿铅、指甲铅均有异常, 指甲铅和血铅水平有较好的相关性。指甲铅水平可作为职业性慢性铅中毒诊断的一个辅助指标, 值得进一步探讨。
     

Visceral adipose tissue and markers of the insulin resistance syndrome in obese black and white teenagers

OBJECTIVE: To determine the relationships between visceral and general adiposity, cardiovascular fitness, and markers of the insulin resistance syndrome in obese black and white teenagers. RESEARCH METHODS AND PROCEDURES: Cross-sectional survey of 81 obese 13- to 16-year-old youths. Visceral adipose tissue was measured with magnetic resonance imaging, and percentage body fat was measured with dual-energy X-ray absorptiometry. Cardiovascular fitness was assessed with a submaximal treadmill test. Fasting blood samples were analyzed for lipids/lipoproteins and insulin. Resting blood pressure was obtained using an automated cuff. RESULTS: Visceral adipose tissue was significantly correlated with unfavorable levels of: triacylglycerol (r = 0.27, p < 0.05), total cholesterol (r = 0.27, p < 0.05), high-density lipoprotein cholesterol (r = -0.26, p < 0.05), the ratio of total cholesterol/high-density lipoprotein cholesterol (r = 0.42, p < 0.01), low-density lipoprotein cholesterol (r = 0.27, p < 0.05), apolipoprotein B (r = 0.38, p < 0.01), and systolic blood pressure (r = 0.30, p < 0.01). Multiple regression analyses revealed that visceral adipose tissue was more powerful than percentage body fat for explaining variance in lipoproteins (e.g., for the ratio of total cholesterol/high-density lipoprotein cholesterol, r2 = 0.13, p < 0.01, and for systolic blood pressure, r2 = 0.07, p < 0.05). Ethnicity was the most powerful of the demographic predictors for blood lipids (r2 = 0.15 for triacylglycerol with lower levels in blacks; r2 = 0.10 for high-density lipoprotein cholesterol with higher levels in blacks; r2 = 0.06 for the ratio of total cholesterol/high-density lipoprotein cholesterol with lower levels in blacks). Cardiovascular fitness was not retained as a significant predictor of markers of the insulin resistance syndrome. DISCUSSION: Some of the deleterious relationships between visceral adiposity and markers for the insulin resistance syndrome seen in adults were already present in these obese young people.     

Urinary Coproporphyrin Isomers I and III in Lead Workers and a Control Group

The excretory pattern of coproporphyrin I and III isomers has been studied in urine from nine health subjects and 10 lead-exposed workers with no clinical evidence of lead poisoning.

In normal urine it was found that coproporphyrin I exceeded coproporphyrin III, whereas in lead workers coproporphyrin III predominated, although this was accompanied by an increase in the absolute amount of coproporphyrin I, indicating active haemopoiesis in lead absorption.