Urinary excretion of cadmium, copper and zinc in workers exposed to cadmium

Changes in urinary cadmium, copper and zinc excretion in workers who had considerable exposure to cadmium oxide fumes were investigated over a 5-year period following the cessation of exposure. The 22 male subjects aged 22 to 55 had been welders on automobile parts for periods ranging from 7 months to 23 years, using silver solder which contained cadmium. They were divided into three groups according to levels of urinary cadmium in the first medical examination in 1975: 5 in the high excretion group, 11 in the moderate group, and 6 in the low group. Renal tubular dysfunctions were indicated in most workers in the high excretion group but not in the other two groups. The high and moderate groups showed a rapid decrease in the levels of urinary-excreted cadmium, with biological half-times of 1.42 and 1.21 years, respectively. Excreted cadmium levelled off in the two groups about 1.7 and 1.5 years after the last exposure. Urinary copper excretion in the high cadmium excretion group was about twice that in the moderate and low groups, the difference being statistically significant in comparison with the controls. Urinary zinc excretion was high in all subjects immediately after cessation of exposure but decreased rapidly. After three years it was found that the reduction of urinary zinc was greatest in the high cadmium group. Urinary cadmium showed significant correlations with both copper and zinc. Urinary copper showed a negative correlation with zinc excretion in the high cadmium excretion group and a significant positive correlation in the other two groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Urinary protein excretion in workers exposed to low doses of cadmium

Conclusions There was evidence of mild renal dysfunction in three of the cadmium-exposed individuals out of the total of 39. However, in none of them did we find a fully developed tubular proteinuria in which moderate increases of total proteinuria, increased lysozymuria and beta-2 microglobulinuria, and excretion of low molecular weight proteins by SDS-PAGE would also be found.Out of the four parameters determined, only one patient had three of them in the abnormal range, but this patient showed predominant elimination of high molecular weight proteins, compatible with glomerular damage, an unexpected finding in cadmium poisoning. Renal dysfunction was detected in one control subject who had increased total protein classified as tubular. There were two abnormal SDS-PAGE patterns found in the control group in which the other parameters measured were normal as was the case in the cadmium exposed patients.     

Urinary neutral endopeptidase in workers exposed to cadmium: interaction with cigarette smoking.

OBJECTIVES: Structural impairment of the renal proximal tubular epithelium induced by cadmium (Cd) was investigated by measuring the concentration of neutral endopeptidase 24.11 (NEP), an ectoenzyme of the apical brush border, in the urine of 106 male workers employed in a Cd smelter (among whom 52 were occupationally exposed to Cd), and by comparing it with other tubular markers (low molecular weight proteins, lysosomal enzymes). METHODS: NEP (EC 3.4.24.11), beta-N-acetyl-glucosaminidase (NAG) (EC 3.2.1.30), and NAG-B isoenzyme activities were measured by fluorimetric assays, whereas the concentrations of retinol binding protein (RBP), beta 2-microglobulin (beta 2M), and Clara cell protein (CC16) were measured by automated latex agglutination techniques. RESULTS: An increased urinary excretion of NEP as well as microproteins was found only in subjects excreting more than 5 micrograms Cd/g creatinine. In this group, NEP concentrations were significantly higher in the subjects who smoked. This significant interaction could not be found for any other marker tested. CONCLUSIONS: The data suggest that NEP enzymuria is high even at low exposures to Cd (with a threshold of urinary cadmium excretion (U-Cd) at 5 micrograms/g creatinine), indicating early structural alterations. Moreover, its particular sensitivity to smoking could be useful in the detection of new population clusters potentially more susceptible to development of nephrotoxic insult.     

Urinary kallikrein activity in workers exposed to cadmium, lead, or mercury vapour

A significant reduction of kallikrein activity in urine (assayed by its amidolytic activity) was found in 64 normotensive workers who had been exposed to cadmium for 11 years on average and whose cadmium concentrations in urine ranged from 2.2 to 33.1 micrograms/g creatinine. The mean (geometric) urinary kallikrein activity (in U/g creatinine) amounted to 0.52 (range 0.11-1.90) in the control group (n = 193) against 0.39 (range 0.10-1.03) in the cadmium group, and the prevalence of abnormally low activity levels (less than or equal to 0.20 U/g creatinine) amounted to 17.2% in the cadmium group against 5.2% in the control group. A reduction of aldosterone release (aldosterone in urine) associated with an increased natriuresis was also observed. This might constitute a compensatory mechanism maintaining blood pressure in the normal range. These biological effects of cadmium were not reversible after removal from exposure. This study indicates that cadmium can induce an irreversible toxic effect in the distal nephron. It also suggests that an excessive cadmium body burden alone may not be sufficient to induce hypertension, but in individuals whose blood pressure regulation may be impaired by other factors cadmium could stimulate the development of hypertension. This study also supports the recommendation to prevent hypertensive subjects from being exposed to cadmium. There was no indication that moderate exposure to mercury vapour (n = 53; mercury in urine, range 11-224 micrograms/g creatinine; average duration of exposure: six years) or to inorganic lead (n = 23; lead in blood, range 40-67 micrograms/100 ml; average duration of exposure: eight years) was associated with a reduction of kallikrein production by the kidney.     

Urinary kallikrein activity in workers exposed to cadmium, lead, or mercury vapour.

A significant reduction of kallikrein activity in urine (assayed by its amidolytic activity) was found in 64 normotensive workers who had been exposed to cadmium for 11 years on average and whose cadmium concentrations in urine ranged from 2.2 to 33.1 micrograms/g creatinine. The mean (geometric) urinary kallikrein activity (in U/g creatinine) amounted to 0.52 (range 0.11-1.90) in the control group (n = 193) against 0.39 (range 0.10-1.03) in the cadmium group, and the prevalence of abnormally low activity levels (less than or equal to 0.20 U/g creatinine) amounted to 17.2% in the cadmium group against 5.2% in the control group. A reduction of aldosterone release (aldosterone in urine) associated with an increased natriuresis was also observed. This might constitute a compensatory mechanism maintaining blood pressure in the normal range. These biological effects of cadmium were not reversible after removal from exposure. This study indicates that cadmium can induce an irreversible toxic effect in the distal nephron. It also suggests that an excessive cadmium body burden alone may not be sufficient to induce hypertension, but in individuals whose blood pressure regulation may be impaired by other factors cadmium could stimulate the development of hypertension. This study also supports the recommendation to prevent hypertensive subjects from being exposed to cadmium. There was no indication that moderate exposure to mercury vapour (n = 53; mercury in urine, range 11-224 micrograms/g creatinine; average duration of exposure: six years) or to inorganic lead (n = 23; lead in blood, range 40-67 micrograms/100 ml; average duration of exposure: eight years) was associated with a reduction of kallikrein production by the kidney.     

镉砷接触工人肾功能损伤研究

目的　探讨镉、砷对作业工人肾功能的联合作用。方法　以我国中南某厂镉、砷作业工人 114名为本研究的职业接触对象。以尿镉 (UCd)、尿砷 (UAs)作为接触标志物 ,尿 β2 微球蛋白(Uβ2 MG)、尿白蛋白 (UALB)、尿N 乙酰 β D 氨基葡萄糖苷酶 (UNAG)作为镉、砷致肾小管和肾小球损害的效应标志物。结果　UCd、UAs水平与Uβ2 MG、UALB、UNAG水平间均为正相关 ,具有明显的剂量-效应关系 (P <0 .0 5 ,P <0 .0 1)。结论　镉、砷对作业工人肾脏功能的联合作用主要表现为相加作用。     

镉接触工人尿镉含量水平影响因素分析

目的分析镉接触工人尿镉含量的影响因素。方法选取深圳市3家镍-镉电池厂镉接触工人375名为接触组,另选取153名未接触镉的上岗前工人作为对照组,分析两组人群的尿镉含量水平,同时对3间镍-镉电池厂工作场所进行职业卫生学调查。结果工作场所空气中氧化镉短时间接触浓度平均为0.027 mg/m3,超标率为37.0%;接触组尿镉含量为(3.36±2.43)μmol/molCr,明显高于对照组[(2.09±1.74)μmol/molCr](P<0.01),接触组女性尿镉含量为(3.68±2.92)μmol/molCr,明显高于男性接触组[(2.76±2.21)μmol/molCr](P<0.01);高浓度组尿镉含量[(3.79±3.41)μmol/molCr]明显高于低浓度组[(2.82±2.12)μmol/molCr](P<0.01),高浓度接触组尿镉异常率(21.9%)也高于低浓度接触组(7.7%)(P<0.01);多元线性回归分析结果显示,工龄、工种(接触浓度)、年龄、性别与尿镉含量的相关系数依次为0.559、0.266、0.233和0.092(均P<0.05)。结论工龄增加、工作场所氧化镉浓度超标是尿镉增高的主要危险因素,降低氧化镉浓度至职业接触限值以下和减少接触时间是预防慢性镉中毒的关键。     

Urinary protein excretion in humans exposed to arsenic and cadmium

OBJECTIVE: In mice, the renal toxicity of arsenic (As) and cadmium (Cd) has been shown to be exacerbated by the simultaneous administration of both elements. To verify the existence of such an interaction in humans, cohorts slightly (Belgian) and moderately (Chinese) exposed to both elements were examined. METHODS: Biological indicators of exposure (Cd in urine and in blood; As in urine) and renal effect parameters (retinol binding protein (RBP); beta(2)-microglobulin (beta(2)M); albumin (ALB); N-acetyl-beta-glucosaminidase (NAG) in urine) were determined and their relationships studied by multiple regression analyses. RESULTS: Changes in renal effect parameters could be ascribed to Cd body burden. RBP and beta(2)M urinary concentration were influenced by exposure to As only in Chinese women, directly and in interaction with Cd exposure. CONCLUSION: A synergistic action of As on the tubular effects of Cd is observed in women moderately exposed to these elements and leads to RBP urinary excretion slightly above normal values.     

Significance of urinary metallothionein in workers exposed to cadmium

Summary Cadmium in blood (Cd-B) and in urine (Cd-U) and metallothionein (Mt-U) and ₂-microglobulin in urine ( ₂m-U) were measured in 94 male Cd workers. The results were examined according to the workers' current exposure to cadmium (group C, n=73, workers currently exposed to Cd; group R, n=21, Cd workers removed from exposure or retired) and according to their renal status (group N, n=66, normal ₂m-U; group 1, n=28, ₂m-U>200 g/g creatinine). The interrelationships between Mt-U, Cd-U, Cd-B and years of cadmium exposure were examined in the various subgroups. The study of the correlations between these variables demonstrates that Mt-U is directly correlated with Cd-U but not with Cd-B or years of Cd exposure. The association between Cd-U and Mt-U is independent of the status of renal function and the intensity of current exposure to cadmium. Under moderate chronic exposure to cadmium, the fraction of Cd-U which is directly influenced by recent exposure (Cd-B) is small in comparison with that influenced by the cadmium body burden.     

镉作业工人的肾脏功能变化

对镉作业工人的肾脏损害进行了探讨,结果表明尿镉低于临界值（5.05μg/gCr),尿中β2-MG、AKP、LDH已显著高于对照组;尿镉高于临界值,尿中β2-MG、AKP、LDH、γ-GT、NAG均升高,建议将β2-MG、AKP、LDH联合应用作为镉作业工人早期检测指标。     

Adverse health effects in workers exposed to cadmium.

One hundred fifty-two workers who had been exposed to different levels of cadmium (Cd) absorption (blood Cd mean 16.34 micrograms/L, median 11.0 micrograms/L) in a factory making nickel-cadmium batteries were studied. A physical evaluation, as well as blood and urine cadmium and N-acetyl-beta-D-glucosaminidase (NAG), and other routine laboratory tests were performed in order to assess the relationship between different levels of exposure to occupational cadmium and potential cadmium-induced renal damage and other adverse health effects. We found significant correlation between levels of cadmium exposure and a selected group of symptoms and signs. The best predictor of this group of symptoms and signs was an indicator called internal dose index (Cd x exposure time). This indicator appears as the strongest, even after control by confounding factors, such as age and smoking. It is concluded that this index can be used for biological monitoring.     

汞作业工人尿N-乙酰-β-D-氨基葡萄糖苷酶活性测定

目的 探讨汞接触工人尿N－乙酰－β－D氨基葡萄糖苷酶（NAG）活性。方法 对某灯泡厂接触不同浓度汞的77名工人进行尿NAG活性测定。并对车间空气汞浓度，尿汞含量，汞作业工龄的关系进行相关分析。结果 接汞组尿NAG活性明显高于对照组（P＜0．005）。尿NAG活性随环境空气汞浓度的增高而逐渐升高，并具有明显的剂量反应关系。但汞作业工龄与NAG之间无显著性（P＞0．05）。结论 在低浓度汞接触时，NAG活性增高较尿汞异常出现得早。建议将尿NAG活性作为汞接触人群健康监护指标之一，在职业健康监护体检中与尿汞同时进行检测。     

Urinary mutagenicity in chemical laboratory workers exposed to solvents

Solvents represent an important group of environmental pollutants to which people are exposed daily in the workplace. The physico chemical properties of solvents may result in disturbances to cellular structures, including damage to DNA. However, the effects of mixtures of solvents are not well known. Mutations caused by environmental agents are related to cancer development and other degenerative diseases. The work in a research laboratory that uses several types of solvents is equally predisposed to these hazards. In this study, we evaluated the mutagenicity of urine from 29 subjects exposed occupationally to solvents in a chemistry research laboratory and 29 subjects without occupational exposure (controls). Urine samples were collected in polyethylene containers at the end of the work shift. For the concentration and extraction of urine samples the XAD-2 resin was used with acetone as an eluting agent. Several strains of Salmonella typhimurium (TA100, TA98, TA97a, TA1535, YG1024) should be used to assess mutagenic susceptibilities among workers exposed to organic solvents. Different doses of extract (1.5; 3.0; 6.0 and 12.0 ml equivalents of urine per plate) were tested on S. typhimurium strains TA100 and YG1024, with and without metabolic activation. The mutagenic activity, measured in Salmonella typhimurium YG1024 with S9 mix, was significantly greater in urine from workers than from controls (p相似文献   

Significance of cadmium concentration in blood and in urine in workers exposed to cadmium.

All the workers (n = 11) occupied in a small factory producing cadmium salts were followed up during several months. Four of them were newly employed workers. At regular time intervals the workers were equipped with a personal air sampler and cadmium concentrations in blood and in urine were measured. The total airborne concentration of cadmium at the different work places was very high. The median values ranged from 110 to 2125 μg/m³. In view of the hygiene practice of the workers, ingestion of cadmium may also have played a role in the overall exposure. After the start of the exposure, cadmium concentration in blood increases linearly up to 120 days and then levels off. This suggests that when equilibrium is reached cadmium level in blood is a good indicator of the average intake during recent months. The interpretation of the cadmium levels in urine is more complex. In seven workers exposed for more than 250 days cadmium level in urine seemed to reflect mainly current exposure. Our results suggest also the existence of three phases in the evolution of the Cd levels in urine after the onset of high exposure. A first phase of very short duration (0–15 days) is observed during which cadmium level in urine increases rapidly to reach a value of about 15 μg/g creatinine. This is followed by a second phase (15–120 days) during which cadmium level in urine increases more slowly. After 120 days there is apparently a rapid increase of the cadmium level in urine (third phase). The results obtained during this study as well as our previous clinical observations on workers exposed to cadmium lead us to propose a tentative biological threshold of 10 μg Cd/g urinary creatinine. It should be stressed that this proposal applies only to adult males occupationally exposed to cadmium and not necessarily to other groups of the general population.     

Urinary levels of proteins and metabolites in workers exposed to toluene

Summary We measured urinary excretion of albumin and retinol-binding proteins to investigate the occurrence of early renal dysfunction in 45 paint workers exposed principally to toluene, and in the same number of unexposed control subjects matched individually for sex and age. Two biological indicators of personal toluene absorption, namely urine hippuric acid and o-cresol, were also measured in the exposed subjects. A significantly higher level and increased prevalence of elevated retinol-binding protein in the urine of exposed workers was found, whereas no significant difference in urinary albumin concentration was seen between the two groups. Urinary concentrations of retinol-binding protein was correlated (r = 0.399, P < 0.006) with that of o-cresol, but not with hippuric acid or employment duration. The results suggest a dose-dependent early tubular effect due to toluene exposure that might be useful for monitoring individuals exposed to toluene at work.