Protective effects of metallothionein and vitamin E in the trunk kidney and blood of cadmium poisoned Ctenopharyngodon idellus

Cadmium (Cd), a substance with one of the most critical health hazard indices, can cause damage to both the blood and kidneys and accumulates in the body at last. The present work studied the toxicological effects of Cd and the therapeutic effects of metallothionein (MT) and vitamin E (VE) on the trunk kidney and blood of freshwater grass carp (Ctenopharyngodon idellus). Grass carp were divided into three groups: Cd + phosphate-buffered saline (PBS) group, Cd + VE group, and the Cd + MT group. Fish were injected with CdCl₂ on the first day and then VE, MT, or PBS was administered 4 days post-injection. Fish not injected with Cd were used as a negative control. The blood and trunk kidney amassed Cd and suffered severe damage in the forms of organ toxicity cytotoxicity, and immunotoxicity. However, the MT reduced the Cd content in the trunk kidney and blood and partially stabilized the damaged organs. Treatment with VE, however, only demonstrated weaker protection against on Cd-induced toxicity. The results indicate that exogenous MT may play an essential role in restoring homeostasis of the Cd-poisoned urinary and circulatory system and that it may help eliminate Cd in aquatic animals.

Protective Role of Zinc and Magnesium against Cadmium Nephrotoxicity in Male Wistar Rats

Cd is a toxic metal that has a destructive impact on most organ systems. This work aims to determine Zn or Mg protective effects against Cd renal toxicity. In this study, rats were divided into six groups. The Cd group was treated with 1 mg Cd/kg, and the control group received 0.5 cm³ normal saline, intraperitoneally. The other four groups received one of the following dosages of 1 mg/kg Cd + 0.5 mg/kg Zn, 1 mg/kg Cd + 1.5 mg/kg Zn, 1 mg/kg Cd + 0.5 mg/kg Mg, or 1 mg/kg Cd + 1.5 mg/kg Mg through IP injection for 3 weeks. Kidney malondialdehyde (MDA) and serum sodium, potassium, urea, creatinine, and protein were measured. Light microscopic examination was used for histological studies. Cd reduced serum creatinine and protein, and increased urea, sodium, and potassium. Moreover, Cd exposure caused a significant enhancement in MDA levels as well as histological damage in kidneys. Zn or Mg treatment prevented and reversed toxic alterations induced by Cd. These results suggest that Zn and Mg may have protective effects against Cd renal toxicity.

The impact of subchronic cadmium poisoning on the vascular effect of nitric oxide in rats

The aim of this study was to evaluate the impact of poisoning with cadmium in hypertensive doses (50 or 200 ppm in drinking water for three months) on the basal and stimulated release NO effect in the isolated and perfused rat mesenteric bed. Mesenteric artery preparation preconstricted by norepinephrine (0.5 μg/mL) was used to determine changes in its vascular resistance induced by e-NOS synthase blocker, N-ω-nitro-L-arginine (L-NOARG) injected in increasing doses from 1.0 to 200.0 μg or acetylcholine (ACh) administered in doses from 0.05 × 10-10 to 5.0 × 10-10 mol before and during L-NOARG infusion (1.0 μg/mL). Vascular reactivity was measured as an increase or decrease in perfusion pressure in the constant flow system.

Rats poisoned with 50 or 200 ppm of cadmium demonstrated a significant decrease (P < 0.05) in vascular response to L-NOARG used in doses of 50 or 100 μg. The dose-response curve obtained for L-NOARG was shifted to the right and ED50 value was greater in the group of rats given cadmium in a dose of 200 ppm than in the controls (70.39 ± 10.7 versus 25.79 ± 4.8 μg, P < 0.01). These rats reacted with lower expressed vasodilatation to ACh in doses to 0.2 ± 10-10 mol. In all poisoned rats, L-NOARG enhanced the effect of ACh used in doses from 0.05 to 0.5 ± 10-10 mol, whereas in the control group this effect was only achieved at 0.1 ± 10-10 mol. The serum nitric oxide concentration was decreased (P B < 0.05) in both groups of cadmium-treated rats. These results suggest that cadmium in hypertensive doses modifies the vascular effect of NO in basal conditions and after stimulation by ACh.

Cadmium exposure and incidence of heart failure and atrial fibrillation: a population-based prospective cohort study

OBJECTIVES

Cadmium is a non-essential toxic metal with multiple adverse health effects. Cadmium has been shown to be associated with cardiovascular diseases, but few studies have investigated heart failure (HF) and none of them reported atrial fibrillation (AF). We examined whether cadmium exposure is associated with incidence of HF or AF.

DESIGN

A prospective, observational cohort study with a 17-year follow-up.

SETTING

The city of Malmö, Sweden.

PARTICIPANTS

Blood cadmium levels were measured in 4378 participants without a history of HF or AF (aged 46-67 years, 60% women), who participated in the Malmö Diet and Cancer (MDC) study during 1992-1994.

PRIMARY AND SECONDARY OUTCOME MEASURES

Incidence of HF and AF were identified from the Swedish hospital discharge register.

RESULTS

143 participants (53% men) were diagnosed with new-onset HF and 385 individuals (52% men) were diagnosed with new-onset AF during follow-up for 17 years. Blood cadmium in the sex-specific 4th quartile of the distribution was significantly associated with incidence of HF. The (HR, 4th vs 1st quartile) was 2.64 (95% CI 1.60 to 4.36), adjusted for age, and 1.95 (1.02 to 3.71) after adjustment also for conventional risk factors and biomarkers. The blood cadmium level was not significantly associated with risk of incident AF.

CONCLUSIONS

Blood cadmium levels in the 4th quartile were associated with increased incidence of HF in this cohort with comparatively low exposure to cadmium. Incidence of AF was not associated with cadmium.

S100β in heavy metal-related child attention-deficit hyperactivity disorder in an informal e-waste recycling area

Exposure to lead even at low levels correlates with attention-deficit/hyperactivity disorder (ADHD). However, lead-contaminated environments are often contaminated with other heavy metals that could exacerbate lead-induced ADHD. We conducted this study to evaluate the relationship between multiple heavy metals and child behaviors, and the involvement of S100 calcium-binding protein β (S100β) expression in child ADHD in Guiyu, an internationally-known e-waste contaminated recycling town. Two hundred and forty kindergarten children, 3- to 7-years of age, who lived in Guiyu, were recruited for this study. Child behavioral assessment was derived from parent and teacher ratings. Serum S100β was assayed by an enzyme-linked immunosorbent assay (ELISA). Lead (Pb), cadmium (Cd) and manganese (Mn) levels in whole blood were measured using graphite furnace atomic absorption spectrometry (GFAAS). The prevalence of children with ADHD symptoms in Guiyu was 18.6%, with the percentage of children suspected to have behavior problems being 46.2% or 46.5%, based on the Rutter parents' or teachers' scale scores, respectively. Child blood levels of Pb, Cd, and Mn correlated with certain behavioral abnormalities, such as conduct problems and antisocial behavior. Serum S100β levels were associated with heavy metal levels in blood, and certain behavioral abnormalities. These findings suggest that exposure to various environmental heavy metals in Guiyu might result in child behavior disorders. Results also indicate that S100β may provide information for laboratory evaluation of neurotoxicity.

Preeclampsia induced by cadmium in rats is related to abnormal local glucocorticoid synthesis in placenta

BACKGROUND

Cadmium (Cd) is a major environmental pollutant that causes multiple adverse health effects in humans and animals. In this study, we investigated Cd-mediated toxic effects in rats during pregnancy and endocrine intervention in the placenta.

METHODS

We exposed pregnant rats to intraperitoneal Cd (CdCl2) at various doses (0, 0.25, and 0.5 mg/kg BW/day) from days 5 to 19 of pregnancy and evaluated the maternal-placental-fetal parameters linked to preeclampsia. We measured the corticosterone level in rat serum and placental tissue by sensitive ELISA and also analyzed the expression of glucocorticoid synthesis enzymes in the placenta.

RESULTS

Key features of preeclampsia (PE), including hypertension, proteinuria, glomerular endotheliosis, placental abnormalities and small fetal size, appeared in pregnant rats after injection with 0.5 mg/kg BW/day Cd. The placental corticosterone production and maternal and fetal plasma corticosterone levels were increased in rats treated with 0.5 mg/kg BW/day Cd (P <0.01). The expression of 21-hydroxylase (CYP21) and 11beta-hydroxylase (CYP11B1), enzymes essential for corticosteroid synthesis, were increased in Cd-exposed placenta (P <0.01). 11beta-hydroxysteroid dehydrogenase (11beta-HSD2), a dominant negative regulator of local glucocorticoid levels, was decreased in Cd-exposed placenta (P <0.01).

CONCLUSIONS

Our study demonstrates for the first time that changes in placental glucocorticoid synthesis induced by Cd exposure during pregnancy could contribute to preeclamptic conditions in rats.

Gut microbiota limits heavy metals burden caused by chronic oral exposure

Environmental exposure to pollutants such as heavy metal(s) is responsible for various altered physiological functions which are detrimental for health. The gut microbiota is critical for intestinal homeostasis but its role on xenobiotic handling is not fully understood, especially when continuous sub-chronic exposure is addressed. We first confirmed the essential role of the intestinal microbiome to limit heavy metal body burden by using germ-free mice following 6-weeks oral exposure. Significant increases of cadmium and lead absorption and dissemination in blood and target organs were measured in germ-free mice when compared with conventional specific pathogen free (SPF) mice. Besides the "barrier" function of the luminal microbiota, this may involve specific host-genes such as metallothioneins, which are differentially expressed in the gastrointestinal tract of each group of mice. Considering genes relevant for divalent metal transporters and oxidative pathways, significant differences in basal gene expression were measured between control and germ-free mice. Moreover, the magnitude of induction of these genes upon stimulation by heavy metals varied greatly depending on the dose and type of metal as well as the microbial status of the animal. Collectively, these data illustrate the complex host-microbes interplay occurring with environmental pollutants inside the gut.

Cadmium exposure induces hematuria in Korean adults

INTRODUCTION

Toxic heavy metals have adverse effects on human health. However, the risk of hematuria caused by heavy metal exposure has not been evaluated.

METHODS

Data from 4701 Korean adults were obtained in the Korean National Health and Nutritional Examination Survey (2008-2010). Blood levels of the toxic heavy metals cadmium, lead, and mercury were measured. Hematuria was defined as a result of ≥+1 on a urine dipstick test. The odds ratios (ORs) for hematuria were measured according to the blood heavy metal levels after adjusting for multiple variables.

RESULTS

Individuals with blood cadmium levels in the 3rd and 4th quartiles had a greater OR for hematuria than those in the 1st quartile group: 3rd quartile, 1.35 (1.019-1.777; P=0.037); 4th quartile, 1.52 (1.140-2.017; P=0.004). When blood cadmium was considered as a log-transformed continuous variable, the correlation between blood cadmium and hematuria was significant: OR, 1.97 (1.224-3.160; Ptrend=0.005). In contrast, no significant correlations between hematuria and blood lead or mercury were found in the multivariate analyses.

DISCUSSION

The present study shows that high cadmium exposure is associated with a risk of hematuria.

Effects of phytate on thyroid gland of rats intoxicated with cadmium

Cadmium (Cd) is one of the most dangerous occupational and environmental toxins. The objective of the present study is to examine the potential prophylactic effects of phytic acid (PA) on thyroid hormones of male rats intoxicated with Cd. The male albino rats were divided into five groups: group I (control) was fed with the basal diet, group II was intoxicated with Cd in drinking water, groups III, IV, and V were intoxicated with Cd in drinking water and fed with the diet containing 3.5, 7, and 10 g of PA/kg, respectively. The results indicated that the serum calcium, iron (Fe), and total Fe binding capacity levels and serum T3 and T4 in Cd-treated rats of group II were decreased when compared with the control group, while PA-administered groups with Cd showed a significant improvement when compared with the Cd-treated rats only. Serum thyroid stimulating hormone (TSH) level was significantly increased in Cd-treated rats compared with the control group, while the addition of PA in diet decreased the high levels of TSH. These results indicated a prophylactic effect of PA against Cd-induced toxicity in rats.

[Sexual specificity of change of pancreatic alpha-amylase activity in rats in cadmium intoxication]

It was shown that the activity of alpha-amylase in the pancreas tissue, intestine content and blood, as well as kinetic characteristics in different substratum concentration changed in males and females after unitary oral administration of chloride cadmium in the dose 5 mg/kg. It was revealed that, after a single administration of chloride cadmium, growth of the pancreas weight, contents of protein and activity of alpha-amylase in the pancreatic tissue increased with parallel reduction of activity of enzyme in the small intestine. In acute cadmium intoxication, functional reorganizations in the pancreas are identical to initial stages of carcinogenic shifts. Such shifts are more expressed in females in comparison with males, especially after the cadmium intoxication.

[The effect of lead and cadmium on the lipid profile and psychosocial functioning of children with developmental disorders]

INTRODUCTION

Impulsiveness, hyperactivity, and attention deficit are the most frequent neurocognitive disorders of childhood. Leaving aside the putative role of environmental and nutritive factors, the etiology and pathogenesis of these disorders remains unknown. The aim of this study was to examine the relationship between the concentration of lead, cadmium, and polyunsaturated fatty acids, and functioning of the child with developmental disorders.

MATERIAL AND METHODS

The study enrolled 78 children with behavioral disorders. The mean age of the children was eight years. Standardized tools were used: Manfred Cierpka Family Assessment Measures, Children's Health Questionnaire Parent Form-28, and ADHD-Rating Scale-IV. Concentrations of lead and cadmium in venous blood, lipid profile, and the percentage of some omega-3 and omega-6 fatty acids in the erythrocyte membrane were measured.

RESULTS

A correlation between higher levels of lead in blood of the child and impulsive and hyperactive behaviors at home was observed. Concentrations of cadmium correlated with increased incidence of attention deficit at school. Analysis of the health profile revealed that lead and cadmium correlate with some of the elements that make up the image of a properly functioning child. Reduced levels of AA and EPA positively correlated with the incidence of hyperactive and impulsive behaviors. Reduced levels of GLA impaired the acceptance of norms and values. Levels of EPA and DHA had an impact on the overall state of health of the child, as well as on physical activity and feeling of loneliness.

CONCLUSIONS

1. Developmental disorders at school and difficulties in functioning at home may be the consequence of dysfunctions caused by lead and cadmium. 2. Deficiencies of AA, GLA, DHA, and EPA fatty acids or a disorder of their metabolism affect the behavior of the child in the form of hyperactivity, impulsiveness, and attention deficit.

Cadmium exposure in association with history of stroke and heart failure

BACKGROUND

It is unclear whether environmental cadmium exposure is associated with cardiovascular disease, although recent data suggest associations with myocardial infarction and peripheral arterial disease.

OBJECTIVE

The objective of this study was to evaluate the association of measured cadmium exposure with stroke and heart failure (HF) in the general population.

METHODS

We analyzed data from 12,049 participants, aged 30 years and older, in the 1999-2006 National Health and Nutrition Examination Survey (NHANES) for whom information was available on body mass index, smoking status, alcohol consumption, and socio-demographic characteristics.

RESULTS

At their interviews, 492 persons reported a history of stroke, and 471 a history of HF. After adjusting for demographic and cardiovascular risk factors, a 50% increase in blood cadmium corresponded to a 35% increased odds of prevalent stroke [OR: 1.35; 95% confidence interval (CI): 1.12-1.65] and a 50% increase in urinary cadmium corresponded to a 9% increase in prevalent stroke [OR: 1.09; 95% CI: 1.00-1.19]. This association was higher among women [OR: 1.38; 95% CI: 1.11-1.72] than men [OR: 1.30; 95% CI: 0.93-1.79] (p-value for interaction=0.05). A 50% increase in blood cadmium corresponded to a 48% increased odds of prevalent HF [OR: 1.48; 95% CI: 1.17-1.87] and a 50% increase in urinary cadmium corresponded to a 12% increase in prevalent HF [OR: 1.12; 95% CI: 1.03-1.20], with no difference in sex-specific associations.

CONCLUSIONS

Environmental exposure to cadmium was associated with significantly increased stroke and heart failure prevalence. Cadmium exposure may increase these important manifestations of cardiovascular disease.

[Clinical and biochemical syndromes of cadmium-induced acute porphyrinopathy]

AIM

To study the specific features of porphyrin metabolic disturbances in cadmium poisoning.

MATERIAL AND METHODS

The paper describes a patient who has developed clinical and biochemical syndromes of acute porphyrinopathy after exposure to cadmium-containing paint the vapors. The levels of delta-aminolevulinic acid, porphobilinogen, coproporphyrin, and uroporphyrin in urine and those of coproporphyrin and protoporphyrin in feces were measured. The concentrations of lead, cadmium, and copper were determined in whole blood and urine; selective screening of amino acids for hereditary metabolic diseases was made.

RESULTS

The clinical signs of acute porphyrinopathy developed in the patient mimicked those of acute porphyries known by the current classification. The biochemical syndrome more corresponded to lead poisoning. However, the blood and urinary lead levels were not greater than the normal values, but the blood showed a 4-fold increase in cadmium, which seemed to induce porphyrin dysmetabolism.

Association of environmental cadmium exposure with inflammation and malnutrition in maintenance haemodialysis patients

BACKGROUND

Chronic inflammation and malnutrition are associated with increased risk of cardiovascular death, and may cause protein-energy wasting in individuals with chronic kidney disease. Raised blood cadmium (Cd) levels were observed in maintenance haemodialysis (HD) patients in previous studies. However, the correlation of Cd exposure with inflammation and malnutrition remains uncertain. This study examined the possible adverse effects of environmental Cd exposure in maintenance HD patients.

METHODS

A total of 954 maintenance HD patients were enrolled and divided into four equal-sized groups based on blood Cd levels. Geographic, haematological, biochemical and dialysis-related data were obtained. The analysis included values for nutritional and inflammatory markers.

RESULTS

Abnormal blood Cd levels (> or =1 microg/L) were exhibited in 26.8% (256/954) of studied subjects. More subjects in the highest quartile group were malnourished (chi- square = 23.27; P < 0.0001) and had inflammatory changes (chi-square = 13.99; P = 0.0029) than in the lowest quartile group. Stepwise multiple regression analysis revealed a significant inverse correlation between serum albumin and blood Cd levels. Notably, a 10-fold increase in blood Cd levels was associated with a 0.06 g/dL decrease in serum albumin levels (P = 0.0060). Multivariate regression analysis also demonstrated a positive correlation between inflammatory risk (high-sensitivity C-reactive protein >3 mg/L) and blood Cd levels. The risk ratio of inflammation with a 10-fold increase in blood Cd levels was 1.388 (95% CI: 1.025-1.825, P = 0.0336).

CONCLUSIONS

Environmental Cd exposure is significantly associated with malnutrition, inflammation and even protein-energy wasting in maintenance HD patients. It is important for this population to avoid diets with high Cd concentrations and smoking.

Cadmium- and lead-induced apoptosis in mallard erythrocytes (Anas platyrhynchos)

Cadmium, lead and cadmium-lead (1:10) induced apoptosis were studied using mallard blood cells. The allowable range in concentrations were: 0.01-0.5, 0.1-5.0, and 0.01:0.10-0.50:5.00 mM, for cadmium, lead and cadmium-lead, respectively. The lowest EC(50) achieved was for cadmium (0.22+/-0.04 mM). Two doses from each treatment group were chosen to study apoptosis and the presence of metals in cells. The percentage of apoptotic cells increased as the concentration of metals increased. The percentage of cells with intracellular metals was high for both exposure levels and the quantity of intracellular metal was greater for exposure to high concentrations. Morphological alterations for all types of exposure were related to the diverse range of effects that these metals have on membranes. We suggest that the decrease in the number of erythrocytes observed in specimens suffering from lead and cadmium poisoning is related to the induction of apoptosis.

Milk trace elements in lactating cows environmentally exposed to higher level of lead and cadmium around different industrial units

The present investigation was carried out to assess the trace mineral profile of milk from lactating cows reared around different industrial units and to examine the effect of blood and milk concentration of lead and cadmium on copper, cobalt, zinc and iron levels in milk. Respective blood and milk samples were collected from a total of 201 apparently healthy lactating cows above 3 years of age including 52 cows reared in areas supposed to be free from pollution. The highest milk lead (0.85+/-0.11 microg/ml) and cadmium (0.23+/-0.02 microg/ml) levels were recorded in lactating cows reared around lead-zinc smelter and steel manufacturing plant, respectively. Significantly (P<0.05) higher concentration of milk copper, cobalt, zinc and iron compared to control animals was recorded in cows around closed lead cum operational zinc smelter. Analysis of correlation between lead and other trace elements in milk from lactating cows with the blood lead level>0.20 microg/ml (n=79) revealed a significant negative correlations between milk iron and milk lead (r=-0.273, P=0.015). However, such trend was not recorded with blood lead level<0.20 microg/ml (n=122). The milk cobalt concentration was significantly correlated (r=0.365, P<0.001) with cadmium level in milk and the highest milk cadmium (>0.10 to 0.39 microg/ml) group had significantly (P<0.05) increased milk cobalt. It is concluded that increased blood and milk lead or cadmium level as a result of natural exposure of lactating cows to these environmental toxicants significantly influences trace minerals composition of milk and such alterations affect the milk quality and nutritional values.

Zinc or magnesium supplementation modulates cd intoxication in blood, kidney, spleen, and bone of rabbits

The objective of this study was to examine the influence of oral supplementation with Zn or Mg on Cd content in the blood and organs of rabbits exposed to prolonged Cd intoxication. Rabbits were divided into the following groups: Cd group-received orally every day for 4 weeks 10 mg Cd/kg body weight (b.w.), Cd+Zn group and Cd+Mg group-exposed to Cd and supplemented with 20 mg Zn/kg b.w. or 40 mg Mg/kg b.w. 1 h after Cd treatment. Cd content in biological material was determined by atomic absorption spectrophotometry. Blood Cd concentration was determined in all investigated groups at time 0 and after 10, 14, 18, 22, 25, and 28 days, whereas Cd content in the brain, heart, lungs, liver, kidney, spleen, pancreas, skeletal muscle, and bone was determined after 28 days. Blood Cd concentration was significantly increased in all groups from the 14th day of Cd intoxication and lasted till the end of the experiment. Zn or Mg supplementation significantly reduced blood Cd content on the 18th and 25th days. Supplementation with Zn or Mg significantly decreased Cd concentration in the kidney, spleen, and bone and, in addition, Zn reduced Cd content in the brain. Supplementation with Zn or Mg in Cd-intoxicated rabbits caused similar reduction of blood Cd concentration; however, reduction of tissue Cd content was more pronounced in Zn- than in Mg-supplemented group.

Trace Mineral Profile in Blood and Hair from Cattle Environmentally Exposed to Lead and Cadmium Around Different Industrial Units

The present investigation was carried out to assess the trace mineral profile in blood and hair from cows environmentally exposed to lead and cadmium and to examine if these toxic heavy metals in blood and hair could affect blood copper, cobalt, zinc and iron concentrations and their accumulation in hair. Respective blood and tail hair samples were collected from adult cows above 3 years, reared in different industrial localities. Samples were also collected from urban areas with small industrial units (n = 55) and areas supposed to be free from pollution. The concomitant exposure of animals to both the heavy metal pollutants was not recorded in either of the industrial or urban locality. Blood lead was significantly (P < 0.01) correlated with blood copper (r = -0.339), cobalt (r = -0.224) and iron (r = -0.497). The increasing blood lead concentrations, irrespective of area of collection of samples, was associated with declining blood copper and iron, and cows with blood lead level above 0.60 mug/ml had significantly (P < 0.05) lower blood copper and iron. The higher blood lead but not cadmium significantly influenced the accumulation of lead (r = 0.323, P < 0.01) and cadmium (r = 0.204, P < 0.01) in hair possibly leading to significantly (P < 0.05) higher accumulation of both lead and cadmium in hair from cattle around lead-zinc smelters and closed lead-cum-operational zinc smelter, where blood cadmium level was comparable with that from unpolluted area. Concentration of zinc (r = 0.237, P < 0.01) and iron (r = 0.183, P < 0.01) but not copper and cobalt in tail hair was significantly influenced by their respective blood concentration. Both the hair lead and cadmium had a significant (P < 0.01) positive correlation with hair copper (r = 0.234, 0.294), zinc (r = 0.489, 0.775), and iron (r = 0.385, 0.643) concentrations. Thus, it is concluded from the present study that the higher blood lead concentrations in cattle irrespective of locality/industrial operations areas affected trace elements profile in blood and hair.

Anthropometric, environmental, and dietary predictors of elevated blood cadmium levels in Ukrainian children: Ukraine ELSPAC group

No comprehensive data on sources or risk factors of cadmium exposure in Ukrainian children are available. In this we measured the blood levels of cadmium among 80 Ukrainian children and evaluated sources of exposure. A nested case-control study from a prospective cohort of Ukrainian 3-year-old children was conducted. We evaluated predictors of elevated blood cadmium using a multivariable logistic regression model. The model included socioeconomic data, parent occupation, environmental tobacco smoke, hygiene, body-mass index, and diet. Dietary habits were evaluated using the 1992 Block-NCI-HHHQ Dietary Food Frequency survey. Elevated cadmium was defined as blood levels in the upper quartile (0.25 microg/L). The mean age for all 80 children was 36.6 months. Geometric mean cadmium level was 0.21 microg/L (range = 0.11-0.42 microg/L; SD = 0.05). Blood cadmium levels were higher among children taking zinc supplements (0.25 vs 0.21 microg/L; P = 0.032), children who ate sausage more than once per week (0.23 vs 0.20; P = 0.007) and children whose fathers worked in a by-product coking industry (0.25 vs 0.21; P = 0.056). In the multivariable model, predictors of elevated blood cadmium levels included zinc supplementation (adjusted OR = 14.16; P < 0.01), father working in a by-product coking industry (adjusted OR = 8.50; P = 0.03), and low body mass index (<14.5; adjusted OR = 5.67; P = 0.03). This is the first study to indicate a strong association between elevated blood cadmium levels and zinc supplementation in young children. Whole-blood cadmium levels observed in this group of Ukrainian children appear to be similar to those reported in other Eastern European countries.

Markers of cadmium exposure in workers in a cadmium pigment factory after changes in the exposure conditions

The objective of this study was to assess changes in concentrations of cadmium in the blood (Cd-B), cadmium in the urine (Cd-U), beta2-microglobulin in the serum (beta2-mG-S) and beta2-microglobulin in the urine (beta2-mG-U) of workers at a cadmium (Cd) pigment factory in Japan in which exposure conditions improved. We evaluated reversibility of these markers in continuously employed workers in relation to changes in exposure levels resulting from improvements in the workplace and the reduced production of Cd. Our study involved both environmental and biological monitoring. Data were collected for four years. We measured the Cd concentration in the air of each work area, using the time-weighted average (TWA). Cd-B and Cd-U were measured in workers as direct indices of Cd exposure. beta2-mG-S and beta2-mG-U were measured as markers of renal tubular function. Exposure levels were high in all work areas, according to the criteria set by the American Conference of Governmental Industrial Hygienists (ACGIH). Workers' Cd-B and Cd-U concentrations reflected high levels of exposure. Correlation was found between these direct indices and beta2-mG-S concentrations. Since the second year, ambient Cd concentrations decreased and reacted markers have been improved. Our results suggest that Cd-B, Cd-U, beta2-mG-S and beta2-mG-U are appropriate markers for monitoring both the level of Cd exposure and the tubular function of workers. Reversibility of urinary low molecular weight protein was observed in the workers over the four years.

Biochemical effects of lead, zinc, and cadmium from mining on fish in the Tri-States District of northeastern Oklahoma, USA

We assessed the exposure of fish from the Spring and Neosho Rivers in northeast Oklahoma, USA, to lead, zinc, and cadmium from historical mining in the Tri-States Mining District (TSMD). Fish (n = 74) representing six species were collected in October 2001 from six sites on the Spring and Neosho Rivers influenced to differing degrees by mining. Additional samples were obtained from the Big River, a heavily contaminated stream in eastern Missouri, USA, and from reference sites. Blood from each fish was analyzed for Pb, Zn, Cd, Fe, and hemoglobin (Hb). Blood also was analyzed for delta-aminolevulinic acid dehydratase (ALA-D) activity. The activity of ALA-D, an enzyme involved in heme synthesis, is inhibited by Pb. Concentrations of Fe and Hb were highly correlated (r = 0.89, p < 0.01) across all species and locations and typically were greater in common carp (Cyprinus carpio) than in other taxa. Concentrations of Pb, Zn, and Cd typically were greatest in fish from sites most heavily affected by mining and lowest in reference samples. The activity of ALA-D, but not concentrations of Hb or Fe, also differed significantly (p < 0.01) among sites and species. Enzyme activity was lowest in fish from mining-contaminated sites and greatest in reference fish, and was correlated negatively with Pb in most species. Statistically significant (p < 0.01) linear regression models that included negative terms for blood Pb explained as much as 68% of the total variation in ALA-D activity, but differences among taxa were highly evident. Positive correlations with Zn were documented in the combined data for channel catfish (Icralurus punctatus) and flathead catfish (Pylodictis olivaris), as has been reported for other taxa, but not in bass (Micropterus spp.) or carp. In channel catfish, ALA-D activity appeared to be more sensitive to blood Pb than in the other species investigated (i.e., threshold concentrations for inhibition were lower). Such among-species differences are consistent with previous studies. Enzyme activity was inhibited by more than 50% relative to reference sites in channel catfish from several TSMD sites. Collectively, our results indicate that Pb is both bioavailable and active biochemically in the Spring-Neosho River system.

[Effect of selenium on metabolic processes in erythrocytes during cadmium intoxication]

Over the period of cadmium poisoning and its counteracting by selenium the activity of erythrocyte enzymes (lactate dehydrogenase and catalase) and the methemoglobin level have been studied. Selenium was found to have protective effect on stabilization of metabolic processes in erythrocytes that prevents the development of oxidation stress and hypoxia.

Serum vasoactive agents in rats poisoned with cadmium

OBJECTIVES

Mechanisms of the vascular effect of cadmium vary and involve nervous, hormone and intracellular signaling pathways. However, it is still not clear if mechanisms of the vascular effect of cadmium (Cd) include changes in the synthesis or release of vasoactive agents. The aim of this study was to evaluate the impact of subchronic Cd poisoning on blood nitric oxide or endothelin in blood and to relate it to the redox system activity in vessel walls and to blood Cd concentration.

MATERIALS AND METHODS

The study was performed on male Buffalo rats which were given cadmium in drinking water, 50 or 200 ppm, for 12 weeks.

RESULTS

The study showed different dose-dependent changes in toxicological and biochemical status. Mean serum nitric oxide concentration (measured using R&D Systems) was lower in rats poisoned with cadmium compared with the control group (57.7 +/- 7.6 vs. control 65.0 +/- 4.9 micromol/l, p < 0.05), whereas the plasma endothelin-1 level (measured using enzymoimmunoassay) and serum prostaglandin PGF2alpha concentration (determined using R&D System) were similar in all animals. The lipid peroxides concentration (measured colorimetrically) was higher in the group treated with cadmium in a dose of 50 ppm than in controls (5.2 +/- 3.0 vs. controls 1.4 +/- 0.4 nmol/ml, p < 0.001) and gluthatione concentration was decreased in the group treated with cadmium in a dose of 200 ppm as compared with the control group, (1.3 +/- 1.2 vs. control 2.5 +/- 0.9, micromol/l p < 0.05).

CONCLUSIONS

It is concluded, that cadmium induces oxidative stress in both doses, however, the activity of defending mechanisms depends on Cd dose. Oxidative stress can be responsible for decreased nitric oxide concentration in serum. We suppose that the mechanisms of the vascular effect of cadmium vary and are dose-dependent. Cd used in a dose of 50 ppm for three months induces more severe functional vascular disturbances than its dose of 200 ppm.

[Fatty acid composition of lipids in erythrocytes and blood plasma in cadmium intoxication and its correction with unitiol]

The effect of cadmium chloride on the fatty acid composition of lipids of the erythrocytes and blood plasma has been studied. It has been established that in the process of cadmium intoxication the decrease of the level of unsaturated fatty acids takes place and the most considerable changes in the content of oleic and arachidonic acids. It makes possible to assume the disturbance of both the erythrocytes membrane structure and metabolism in the erythrocyte. Unitiol injection promotes the normalisation of the indices under investigation.

Protective influence of vitamin E on antioxidant defense system in the blood of rats treated with cadmium

The effects of acute exposure to cadmium (Cd) on the blood antioxidant defense system, lipid peroxide concentration and hematological parameters, as well as the possible protective role of vitamin E were studied. Male Wistar albino rats (3 months old) were treated with cadmium (0.4 mg Cd/kg b.m., i.p., 24 h before the experiment) or with vitamin E + Cd (20 IU Vit E/kg b.m., i.m., 48 h + 0.4 mg Cd/kg b.m., i.p., 24 h before the experiment). The hematological parameters were assessed: red blood cell counts, hematocrit value and hemoglobin concentration were significantly decreased in the blood of Cd-treated rats. Intoxication with cadmium was also followed by significantly increased lipid peroxide concentrations. We also observed increased activity of antioxidant defense enzymes: copper zinc containing superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione-S-transferase as well as concentrations of non-enzymatic components of antioxidant defense system: reduced glutathione, vitamin C and vitamin E. Pretreatment with vitamin E exhibited a protective role on the toxic effects of cadmium on the hematological values, lipid peroxide concentration as well as on enzymatic and non-enzymatic components of antioxidant defense system.

Toxic trace metals in the mentally ill patients

Serum Cadmium and lead were measured in 61 in- and out-patients of the Mental Health Unit of a University Teaching Hospital. Diagnosis using the ICD-10 Criteria divided the patients into 21 Depressives, 20 Manic-depressive and 20 Schizophrenics. Twenty "healthy" individuals matched for age and sex were used as controls. The measurements of cadmium and lead were done on admission and at 3 and 7 weeks after the relevant treatment had been given. Serum zinc was also measured because of the interaction between zinc and these toxic metals. Measurement was with the Atomic Absorption Spectrophotometer. Results showed that cadmium was raised in depressives (p < 0.02) and reduced in mania patients (p < 0.01). Lead was increased in depressives (p < 0.01) and schizophrenics (p < 0.05) but not in mania patients. Serum zinc was reduced in all mental patients. Serum levels of the toxic metals of the mental patients tended to move towards the values of the control group with treatment.

[Study of hemoglobin system components and antioxidation enzymes in cadmium intoxication]

Cadmium intoxication has been defined to make material changes in hemoglobin system by elevation of sulfhemoglobin and methhemoglobin levels on the back-cloth of lowering of general hemoglobin. Alongside with the latter there is observed a violation of antioxydation protection including the activity of erythrocytic catalase, ceruloplasmin, ferrum saturation of transferrine.

Alterations of serum hormone levels in male workers occupationally exposed to cadmium

In order to investigate the influence of occupational exposure to cadmium (Cd) on the levels of serum hormone, a cross-sectional study was undertaken in male workers. Creatinine-adjusted urinary cadmium (UCd) was used as the indicator of cadmium body burden in workers. The levels of serum testosterone (T), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) were determined by radioimmunoassay and enzyme immunoassay, respectively. The results showed that with cadmium exposure, the levels of serum testosterone and LH were significantly increased after controlling for confounding factors such as age, smoking habits, and alcohol consumption. However, no significant cadmium-associated changes in the levels of serum FSH were found. At the same time, a significant negative correlation of serum testosterone levels with age was detected. In contrast, the levels of serum FSH and LH were significantly elevated with increasing age. When taking the marital status into consideration, only significantly elevated FSH levels were noted in married workers after controlling for confounding factors. These results indicate that occupational cadmium exposure and other factors such as age and marital status may independently contribute to alterations in the levels of serum sex hormones in males.

[High density lipoprotein cholesterol level in rats poisoned with cadmium]

The effect of cadmium on lipid metabolism in persons occupationally and environmentally exposed to this metal may lead to the occurrence of cardiovascular diseases. The disturbances of the reverse transport of cholesterol could be responsible for the vascular changes. The aim of this study was to evaluate the impact of cadmium on the cholesterol level in the main fraction and subfractions of high density lipoprotein (HDL). The cholesterol level was measured in serum of rats treated with cadmium in a weekly dose of 5 mg/kg b.w. for seven weeks and in controls. After a seven-week exposure, the decreased HDL2, and the increased HDL3 cholesterol levels were observed in cadmium-poisoned animals as compared to controls. The results of the study suggest that a cadmium-impaired mechanism of the cholesterol transport in blood may induce vascular changes.

In utero exposure to cadmium pollution in Cairo and Giza governorates of Egypt

Serum cadmium levels at delivery were measured in a consecutive sample of 100 mother-infant pairs in Egypt using venous blood from mothers and umbilical cord blood from neonates. The serum cadmium levels of mothers ranged from 0.4 to 2.2 microg/L (mean 0.73 microg/L) and of infants from 0.2 to 1.5 microg/L (mean 0.66 microg/L). Infant cadmium levels were about 70% of maternal levels in most pairs. Serum cadmium was significantly higher in mothers and babies passively exposed to tobacco smoke. Five-minute Apgar scores were negatively correlated with cord blood cadmium levels. The cadmium levels did not differ between subjects from Cairo and Giza or according to urban, suburban or rural areas. Thus, in utero exposure to cadmium was evident and wider-scale studies on its long-term effects are recommended.

Influence of time period of cadmium intoxication on the concentrations of ascorbic acid selenium in certain tissues and blood serum of rats

Ascorbic acid and selenium are important antioxidants for the reactive forms of oxygen. The purpose of these experiments was to determine the influence of various concentrations of cadmium on ascorbic acid and selenium concentrations in certain tissues of rats. The results showed that cadmium, added to rats' feed, influenced the concentration of ascorbic acid in blood serum and tested rats' tissues. Cadmium influenced the concentration of selenium in certain tissues as well. Furthermore, it has been demonstrated that ascorbic acid and selenium concentrations are dependent on the type of tissue tested as well as on the size of cadmium concentrations and length of the experiments.

Determinants of cadmium burden levels in a population of children living in the vicinity of nonferrous smelters

This report covers part of the assessment of a site in northern France polluted by industrial metal emissions. Our objectives were to assess the cadmium burden in children aged 8 to 11 years and look for factors that affected it. A cross-sectional population-based study took place in 1996-1997 and included 400 children (200 in the metal-polluted area). The geometric mean of the blood cadmium (CdB) levels of children living on the polluted site was 0.51 microg/L (95% CI=[0.49-0.53]); that of the nonexposed children was 0.47 microg/L (95% CI=[0.45-0.49]) (P<0.01). The geometric mean of the urinary cadmium (CdU) levels of children living on the polluted site was 1.16 microg/g creatinine (95% CI=[1.01-1.34]); that of the nonexposed children was 0.99 microg/g creatinine (95% CI=[0.86-1.14]) (P=0.10). Mean CdB was higher among children within 4 km of a zinc smelter and consuming > or =500 ml of tap water daily (x1.34; 95% CI=[1.14-1.51]) compared with children living more than 4 km away and consuming <500 ml of tap water daily. Independently of this association, consumption of fish and shellfish (> or =once a week vs. <once a week) and homegrown vegetables (> or =once daily vs. <once daily) was associated with higher mean CdB levels, respectively: x 1.14; 95% CI=[1.07-1.21] and x 1.25; 95% CI=[1.04-1.50]. Neither sex nor age was associated with CdB. Mean CdU was associated with paternal occupational cadmium exposure.

The German Environmental Survey 1990/92 (GerES II): primary predictors of blood cadmium levels in adults

As part of the representative Environmental Survey in Germany in 1990-1992, investigators determined cadmium levels in blood provided by 3,965 subjects aged 25-69 yr. The investigators considered approximately 150 variables (i.e., demographics, household and occupational characteristics, environmental exposures, smoking habits, frequency of food consumption, and additional life-style features) as potential predictors in multivariate regression analysis. On the basis of the results of multivariate regression analysis, the authors derived 2 slightly different models for the prediction of blood cadmium levels in populations from West and East Germany. Both models included 3 primary predictors of blood cadmium levels. The 2 models explained 51.3% and 61.2% of the observed variance in blood cadmium levels in West and East Germany, respectively. The most important predictor was a specific indicator for smoking habits, which was determined from a separate mathematical model. In this model, the effect of smoking was considered, and the model accounted for the biological half-life of cadmium in blood.

Renal effects of cadmium exposure in cadmium nonpolluted areas in Japan

Long-term exposure to cadmium (Cd) causes renal damage in the general population. The maximum allowable urinary Cd concentration, which was calculated from our previous study performed in a Cd-polluted area, was almost the same as the mean urinary Cd concentration of people living in nonpolluted areas. We assessed whether environmental Cd exposure is related to renal dysfunction of people in nonpolluted areas in Japan. Blood and urine samples were collected from 2753 subjects (1105 men and 1648 women) ages over 50 years old in three nonpolluted areas. Blood was analyzed for Cd and urine was analyzed for Cd, total protein, beta(2)-microglobulin (beta(2)-mg), and N-acetyl-beta-D-glucosaminidase (NAG). Cd in blood or urine was employed as indicators of internal dose; and urinary total protein, beta(2)-mg, and NAG were used as an indicator of renal dysfunction. Multiple regression analysis and logistic regression analysis were performed to clarify the dose-effect and dose-response relationship between blood or urinary Cd concentration and indicators of renal dysfunction. Multiple regression analysis demonstrated a significant dose-effect relationship between Cd in blood and urine and indicators of renal dysfunction. Logistic regression analysis also showed that the probability that individual subjects would have abnormal values of the renal variables was significantly related to Cd in blood and urine.

The concentration levels of Cd, Pb, Hg, Cu, Zn and Se in blood of the population in the Czech Republic

Knowledge of normal levels of concentrations of trace elements (Cd, Pb, Hg, Cu, Zn, and Se) in the population serves, among others, in design of regulations concerning health protection, determination of exposure limits and prevention of diseases caused by deficiency of trace elements. Concentrations of the named elements in whole blood of the Czech population were determined by means of atomic absorption spectrometry. The blood was collected during 1996-1998 from 1,216 blood donors (896 males and 320 females, average age 33 years) and 758 children (397 boys and 361 girls, average age 9.9 years). Mineralisation in a microwave digestion system was used in sample preparation. The accuracy of results was checked by means of the Control material Seronorm Whole Blood 404107 and Seronorm Serum 704121, Nycomed. Values of concentrations of the trace elements in blood found for adult (medians) were 0.7 microgram Cd.l-1, 800 micrograms Cu.l-1, 0.78 microgram Hg.l-1, 41 micrograms Pb.l-1, 76 micrograms Se.l-1, and 5,800 micrograms Zn.l-1, respectively. Statistically significant differences between men and women have been found in the concentrations of Cu, Hg, Pb, and Zn. In the juvenile population following medians of concentrations have been found: 0.15 microgram Cd.l-1, 1,047 micrograms Cu.l-1, 0.46 microgram Hg.l-1, 34 micrograms Pb.l-1, 69 micrograms Se.l-1, and 8,180 micrograms Zn.l-1. Statistically significant differences between boys and girls were found only in Pb and Zn concentrations. Concentrations of the studied elements correspond to the published values concerning population not exposed professionally.

Granulocyte and plasma cytokine activity in acute cadmium intoxication in rats

Changes in the number and ex vivo function of peripheral blood neutrophils were investigated following intraperitoneal administration of cadmium-chloride in rats. Besides a dose-dependent increase in the number of peripheral blood neutrophils, changes were found in the functional state of isolated polymorphonuclear leukocytes (PMNs). Increased spontaneous adhesion and activation, and TNF activity in a conditioned medium were observed in cultures of granulocytes in comparison to granulocytes from control (saline-treated) animals. Increased levels of plasma activity of inflammatory cytokines, tumor necrosis factor (TNF) and interleukin-6 (IL-6) were noted following cadmium administration. Cytological signs of pulmonary inflammation were revealed histologically and the majority of neutrophils recovered from the lungs by enzyme digestion exhibited a capacity of nitroblue tetrazolium (NBT) reduction. Our data demonstrate that acute cadmium intoxication leads to a systemic inflammatory response characterized by numerical and functional changes in the granulocyte compartment and to increased levels of inflammation-related cytokine activity in the circulation. Correlations between the increased number of peripheral blood neutrophils and IL-6 plasma activity (r=0.776, p<0.00001) and the number of neutrophils recovered from the lung tissue (r=0.893, p<0.00001) suggested that systemic cadmium-induced inflammation might be involved in the pulmonary toxicity of cadmium.

Effects of thiamin and methionine administration in preventing cadmium-induced biochemical alterations and metal concentration in male rats

Thiamin or methionine supplementation was equally and moderately effective in preventing the accumulation of cadmium in soft organs and alterations in a few selected biochemical indices during concomitant administration. Adequate intake of sulfur amino acid following methionine supplementation might increase the bioavailability of glutathione, facilitating the prevention of the binding of cadmium to different compartments and consequently reversing cadmium-induced biochemical disorders. In the case of thiamine the possibility of formation of a readily excretable complex between cadmium and thiamine or an increase in the body's resistance to cadmium might be the beneficial factor.

Influence of cadmium intoxication on thromboresistance of vascular endothelium in rabbits

Here, using our original technique for measuring of thrombogenesis on the surface of rabbit aorta endothelium superfused with whole blood, we demonstrate that the thrombogenic property of endothelium is potentiated in the course of 3 months cadmium intoxication. The loss of endothelial thromboresistance is accompanied by suppressed generation of endogenous prostacyclin, leukopenia, increased platelet aggregability and by the presence of quasi-atherosclerotic, focal proliferative, glassy-protein lesions formed in aortic endothelium. We hypothesize that the final loss of vessel thromboresistance with all sequence of events that accompany cadmium intoxication, may result from the cadmium-induced inhibition of the generation of endothelial prostacyclin. However, the exact mechanism by which cadmium intoxication may affect the generation of prostacyclin and, then, functioning of blood platelets and vascular endothelium requires further investigations.

Cadmium in the blood and seminal fluid of nonoccupationally exposed adult male subjects with regard to smoking habits

Blood cadmium (B-Cd) and seminal fluid cadmium (Sf-Cd) were measured in 120 adult male subjects not occupationally exposed to cadmium (Cd), comprising 42 nonsmokers (including nine former smokers) and 78 smokers. The respective median and range values were: 0.46 (0.19-1.49) microgram/l of B-Cd and 0.54 (0.17-1.67) microgram/l of Sf-Cd in nonsmokers, and 4.33 (0.49-13.33) micrograms/l of B-Cd and 0.85 (0.29-3.56) microgram/l of Sf-Cd in smokers. Both indicators showed a highly significant difference in Cd exposure between the groups (P < 0.0001), although the increase in B-Cd was considerably more pronounced than that of Sf-Cd in smokers compared with nonsmokers. The results suggest a nonlinear relationship (log Sf-Cd/log B-Cd: r = 0.501, P < 0.0001), rather than linear relationship (Sf-Cd/B-Cd: r = 0.430, P < 0.0001), between the indicators. Significant correlations were found between smoking habits, i.e., the number of cigarettes per day, and an increase in B-Cd in smokers (r = 0.296, P < 0.01) and in all 120 subjects (r = 0.685, P < 0.0001), as well as between smoking habits and an increase in Sf-Cd in smokers (r = 0.378, P < 0.001) and in all 120 subjects (r = 0.488, P < 0.0001). Both indicators are necessary for evaluation of individual internal Cd dose, since they appear to differ in reflecting recent and long-term cumulative Cd exposure and/or the amount of Cd at the site(s) of its effect(s) in the body.

[Exposure of the Berlin population to aromatic hydrocarbons and heavy metals within the scope of a study of the health effects of vehicular traffic]

As part of an environmentally oriented study, 800 women from two Berlin boroughs, between 30 and 45 years of age, were examined of their exposure to aromatic hydrocarbons, lead, and cadmium. The aim of this investigation was to determine the actual exposure of a representative population of Berlin to these xenobiotics and to evaluate the influence of other factors on the parameters measured in the blood. The geometric average values obtained in the analysis of the blood of the women included in the study, were 30 micrograms/l (144.9 nmol/l) for lead and 0.34 microgram/l (3.04 nmol/l) for cadmium (those who had never smoked 0.25 microgram/l; smokers 0.69 microgram/l). Compared to the 'eighties, blood lead concentration declined and to date only 1% of our study population had values > 100 micrograms/l. Smoking was confirmed to be a major influence factor. There is also a relation between lead in the blood and the use of alcoholic beverages and the presence of lead pipes in drinking water systems of the houses. The geometric means obtained were 0.41 microgram/l for benzene and 0.73 microgram/l for toluene and therefore higher than previously described in the literature. A statistical connection of benzene in blood to the indoor air concentration or the to the average daily traffic density could not be seen, but there is a relation to smoking habits.

Cadmium levels in maternal, cord and newborn blood in Mexico City

Blood samples were withdrawn from n = 49 mothers and their children at the moment of birth to assess blood cadmium levels of the mother, the newborn and the cord. A questionnaire was applied to the mothers in order to obtain data about possible sources of cadmium exposure. Maternal blood cadmium was found significantly correlated (r2 = 0.578) with cord blood cadmium levels, while cord blood was correlated (r2 = 0.499) with newborn blood cadmium. Nevertheless, maternal blood cadmium and newborn blood cadmium were not correlated at all (r2 = 0.047). Previous smoking habits of the mother increased maternal blood cadmium concentrations significantly, but it did not modify cadmium concentrations of either the cord or the newborn. The latter result suggests the existence of a placental barrier for cadmium. Birthweight was found to be inversely associated (P < 0.06) only with cord blood cadmium levels. The results of the study suggest that cord blood cadmium holds information about both maternal and newborn cadmium status and also about cadmium effects on birthweight.

Blood cadmium as an indicator of dose in a long-term follow-up of workers previously exposed to cadmium

OBJECTIVES

This investigation attempted to follow the tubular function of 46 workers initially examined in 1984 and heavily exposed to cadmium from 1955 to 1978 and the occurrence of renal stones among these workers. Three different markers of tubular dysfunction were also studied, and blood cadmium was evaluated as an estimate of dose after the cessation of cadmium exposure.

METHODS

Cadmium in blood (B-Cd) and urine (U-Cd) and the urinary excretion of beta 2-microglobulin (U-beta 2-microglobulin), protein HC (alpha 1-microglobulin) and N-Acetyl-beta-D-glucosaminidase (NAG) were determined.

RESULTS

Although cadmium exposure ceased in 1978, 40% of the workers showed signs of tubular dysfunction both in 1984 and in 1993. The current B-Cd was the best dose indicator. Dose-response relationships were found for B-Cd and various tubular markers (U-beta 2-microglobulin, protein HC and NAG). Protein HC appeared to be the most sensitive, as well as an early, indicator of cadmium-induced tubular dysfunction. The levels of U-Cd had an average decrease of 48% for persons with a normal tubular function, 56% for those with slight tubular dysfunction, and 62% for workers with severe tubular damage. A history of renal stones was significantly more common for workers with high B-Cd levels.

CONCLUSIONS

Cadmium-induced tubular dysfunction is irreversible and best assessed in an analysis of protein HC (alpha 1-microglobulin) in urine. B-Cd is the best dose estimate several years after the cessation of exposure, whereas U-Cd is less suitable for dose assessment in follow-up studies of persons with persistent tubular damage.

Critical evaluation and review of cadmium concentrations in blood for use in occupational health according to the TRACY protocol

Cadmium in blood (B-Cd) may be used to assess recent exposure to cadmium in the working or general environment. In a paper published elsewhere pooled reference values using meta-analysis of B-Cd values in general-population studies were calculated. In the present study tentative references intervals were described which can be used for comparison with data from occupationally exposed groups or individuals. The selection of studies was done according to criteria as published by the international project TRACY. For this purpose, 800 publications covering the period 1983-1992 were reviewed on their suitability for establishing tentative reference intervals. From these 800 publications, four finally met the selection criteria. Most important criteria for selection were the check for contamination during sampling of the blood, the storage and pretreatment procedures, and the existence of internal and external quality control programs. Also, stratifications into sex, smoking habits and occupation were important selection criteria. It turned out that for non-smoking white-collar workers in the age range of 19-65 years, B-Cd values were below 0.8 micrograms/l for most areas. All other groups within this age group, e.g., white collar workers in Japan, blue-collar workers, and smokers tend to have higher B-Cd values in these sequences. Blue-collar workers not clearly exposed to Cd have higher values than white-collar workers, indicating still some minor exposure. It is not clear if this small exposure has an occupational or lifestyle (e.g., diet) origin. Geographical regions also show an influence on B-Cd levels, e.g., values in Japan are higher than elsewhere. This influence may be due to differences in diet. The conclusion will be that reference values for B-Cd in fact are area-dependent.

Background exposure of urban populations to lead and cadmium: comparison between China and Japan

OBJECTIVES

To assess and compare the background exposure of the general population to lead (Pb) and cadmium (Cd) in China and in Japan.

METHODS

Food duplicates and peripheral blood samples were collected from nonoccupationally exposed subjects, viz 202 Chinese women in four Chinese cities (Beijing, Shanghai, Nanning, and Tainan) and 72 Japanese women in three Japanese cities (Tokyo, Kyoto, and Sendai) in the years 1993-1995. Wet-ashing and graphite furnace atomic absorption spectrometric methods were used for the determination of Pb and Cd levels in food and blood samples.

RESULTS

Geometric mean (GM) dietary Pb intake (25.8 micrograms/day) and the GM Pb concentration in blood (56.7 micrograms/l) in Chinese were significantly higher than in Japanese women (11.6 micrograms/day in food and 32.1 micrograms/l in blood), whereas Cd in food (32.1 micrograms/day) and Cd in blood (1.92 micrograms/l) in Japanese were significantly higher than in Chinese women (9.9 micrograms/day in food and 1.07 micrograms/l in blood). The intake of Pb and Cd via boiled rice accounted for 3.6% and 31.1% of the total dietary burden in Chinese, and 12.1% and 32.7% in Japanese, respectively. The Cd burden was acquired almost exclusively through the dietary route, whereas the Pb burden came from both air and food, especially in the case of the Chinese population.

CONCLUSIONS

The background Pb exposure in the Chinese population was higher than that in the Japanese population, whereas Cd exposure was lower in Chinese women than in their Japanese counterparts.

Chronic cadmium exposure-induced renal anemia in ovariectomized rats

Cadmium (Cd) chloride was intravenously injected at doses of 0.05 and 0.5 mg/kg/day in ovariectomized rats for 50 weeks, and the chronic Cd exposure-induced nephrotoxicity and anemia were investigated. The rats treated with 0.05 mg/kg Cd showed no apparent hematological, urinary, and histopathological abnormalities. In the 0.5-mg/kg group, renal tubular disorders became marked at 16 weeks, and cortical fibrosis with glomerular dysfunction appeared at 50 weeks. Anemia occurred at 12 weeks in the 0.5-mg/kg group and became increasingly marked with time. The mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) were decreased at 12 and 25 weeks; however, the decreases of MCV and MCH disappeared at 50 weeks. A slight decrease in mean corpuscular hemoglobin concentration was noted at 50 weeks. The blood chemistry from the same group revealed a decrease in plasma iron levels and an increase in total iron binding capacity throughout the administration period. The erythropoietin (EPO) level was increased as the hemoglobin level decreased at 12 weeks, whereas the EPO level was not elevated even when the hemoglobin level was decreased at 50 weeks. These findings showed that renal anemia also occurred in addition to the iron deficiency anemia at 50 weeks.

Low-level lead exposure, renal function and blood pressure

The possible influence of low-level lead exposure on public health remains a matter of concern. The purpose of this article was to review the evidence that renal function and blood pressure may be affected at exposure levels encountered in the Belgian population. Moreover a meta-analysis explored whether the available studies in man would support a positive association between low-level lead exposure and hypertension. Renal function and lead exposures were studied in Belgium in a random population sample of 965 men and 1016 women (age range: 20 to 88 years). The mean (+/- standard deviation) creatinine clearance was 99 +/- 30 ml/min in men and 80 +/- 25 ml/min in women. In men the geometric mean blood lead concentration was 0.55 mumol/l with range from 0.11 to 3.5 mumol/l and in women 0.36 mumol/l with range from 0.08 to 2.9 mumol/l; the zinc protoporphyrin values in blood averaged 1.0 and 1.1 microgram/g haemoglobin, respectively. The creatinine clearance was negatively correlated with blood lead as well as zinc protoporphyrin values in men and women both before and after adjustments for age, body mass index and diuretic treatment. A tenfold rise in blood lead concentration was associated with a 10 to 13 ml/min reduction in the creatinine clearance. Serum beta 2-micro-globulin and zinc protopohyrin in both sexes, and serum creatinine and zinc protopohyrin in men were also significantly and positively correlated. Blood pressure was also measured in the Belgian population study. The sample, from which patients on antihypertensive treatment had been excluded, included 827 men and 821 women. Systolic/diastolic pressure averaged 131/77 mm Hg in men, and 124/74 mm Hg in women. After adjustment for significant covariates (age, body mass index, pulse rate, serum creatinine and serum calcium, and in women also contraceptive pill intake and menopause), systolic pressure was negatively correlated with blood lead in man (P < 0.05); the partial correlations with blood lead were not significant for systolic pressure in women, nor for diastolic pressure in both sexes. After excluding men exposed at work, the partial correlations between systolic and diastolic pressure and blood lead were negative (P < 0.05). In neither men nor women, there was a significant relation between blood pressure and the zinc protoporphyrin level in blood. A meta-analysis of 23 human studies included 33141 subjects, recruited from the general population in 13 surveys and from occupational groups in 10 studies. In all but 4 studies the results had been adjusted for age, and most studies also considered additional confounders. The association between blood pressure and blood lead was similar in the 2 sexes. In all 23 studies combined, a twofold increase in the blood lead concentration was associated with a 1.0 mm Hg rise in the systolic pressure (95% confidence interval [CI]: 0.4 to 1.6 mm Hg; P = 0.002) and with a 0.6 mm Hg increase in the diastolic pressure (CI: 0.2 to 1.0 mm Hg; P = 0.02). In conclusion, lead exposure may impair renal function in the population at large. However, the alternative hypothesis that renal impairment may lead to an increase in the blood lead concentration cannot yet be excluded with absolute certainty. On balance, the available evidence suggests that there can only be a weak positive association between blood pressure and lead exposure. The latter relationship, which is barely visible at the horizon of epidemiological observation, may not be causal in nature, and is likely to entail any public health implication in terms of hypertension-related complications.

Evaluation of selected parameters of a metabolic profile and levels of cadmium in reproductive organs of rabbits after an experimental administration

Selected serum parameters of metabolic profile and distribution of cadmium in reproductive organs in rabbits were studied after an acute and subchronic administration. After an i.p. application of cadmium (1.5 mg.kg-1) a significant increase of glucose (5.90 mmol.l-1) and cholesterol (2.22 mmol.l-1) was observed. There were no significant differences in these parameters after the subchronic (5 month) p.o. application. The concentration of AST and ALT significantly decreased after a subchronic p.o. administration (1.0 mg.kg-1) but not after an acute i.p. application. There were no significant differences in the level of total proteins and total lipids. The highest accumulation in reproductive organs (testis, ovary, uterus) was observed after i.p. administration. The level in the testis was 40 times higher than in the control group (0.04 mg.kg-1; 1.93 mg.kg-1), 174 times higher in the ovary (0.03; 5.21) and 65 times higher in the uterus (0.04; 2.59). After a subchronic p.o. application, the concentration was only 2.5 times higher in the testis (0.04; 0.10), 16 times higher in the ovary and 6 times higher in the uterus than in the control group.

Cadmium and hypertension

Hypertension is a very common and important disease of modern civilised life. There are comflicting reports about cadmium, a trace element in the genesis of essential hypertension. The present study was conducted to estimate the cadmium levels in whole blood in the normal group of thirty subjects who were normotensive and the same was compared to that of thirty hypertensive patients and the levels were found to be statistically significant (p < 0.05).