Zinc Protoporphyrin Concentrations Research Articles

Lead, hemoglobin, zinc protoporphyrin and ferritin concentrations in children

To assess the relationship of blood lead and hemoglobin, zinc protoporphyrin, and ferritin concentrations in children. A cross-sectional study was carried out in 136 anemic and non-anemic children from two rural villages near a lead smelter in Adrianópolis, Southern Brazil, from July to September 2001. Hemoglobin electrophoresis was performed to exclude children with hemoglobin variants and thalassemia syndromes associated with anemia. Lead was determined by atomic absorption spectrophotometry; hemoglobin by automated cell counting; zinc protoporphyrin by hematofluorometry; ferritin by chemiluminescence. Student's t-test, Mann-Whitney test, and the c(2) test were used to assess the significance of the differences between the variables investigated in anemic and non-anemic children. Stepwise multivariate linear regression analysis was performed using two models for anemic and non-anemic children respectively. Lead was negatively associated to hemoglobin (p<0.017) in the first model, and in the second model lead was positively associated to zinc protoporphyrin (p<0.004) after controlling for ferritin, age, sex, and per capita income. There was an inverse association between hemoglobin and blood lead in anemic children. It was not possible to confirm if anemic children had iron deficiency anemia or subclinical infection, considering that the majority (90.4%) had normal ferritin. The study detected a relationship between anemia and elevated blood lead concentrations. Further epidemiological studies are necessary to investigate the impact of iron nutritional interventions as an attempt to decrease blood lead in children.

Feeding practices and factors contributing to wasting, stunting, and iron-deficiency anaemia among 3-23-month old children in Kilosa district, rural Tanzania.

Infants in Tanzania are particularly vulnerable to under-nutrition during transition from breastmilk (as the only source of nourishment) to solid foods. A cross-sectional study was undertaken in Kilosa district in Tanzania to determine the feeding practices and the extent of wasting, stunting, and iron-deficiency anaemia. The study was done in two stages: in the first stage, a 24-hour dietary assessment was conducted to identify the type of complementary foods given and the eating habits according to age for 378 children aged 3-23 months. In the second stage, a progressive recruitment of 309 infants aged six months was made to measure weight, length, haemoglobin (Hb) concentration, zinc protoporphyrin concentration, and malaria parasitaemia. Birth-weight, the potential contributing factor to under-nutrition and iron-deficiency anaemia, was obtained from the children's clinic cards. The 24-hour dietary assessment revealed that children consumed mainly a thin porridge prepared from maize flour as complementary food. Carbohydrates contributed most energy (on average 69%), followed by fats (18.6%) and protein (on average 12.1%). The complementary food co-vered only 15%, 20%, and 27% of the recommended iron intake for children aged 6-8, 9-11 and 12-23 months respectively. The mean Hb concentration was 9.3 +/- 1.9 g/dL, 68% of the infants were moderately anaemic (7 < or =11 g/dL), and about 11% were severely anaemic with Hb below 7 g/dL, while 21% were non-anaemic Hb (> or =11 g/dL). Equally, the mean zinc protoporphyrin concentration was 10.0 +/- 6.2 microg/g Hb, and 76% of the infants were iron-deficient (>5 microg/g Hb). The prevalence of stunting was 35%, while wasting was only 1.3%. Low birth-weight and low body mass index of mothers were the strong predictors of stunting, whereas low birth-weight and iron-deficiency were the strong predictors of anaemia. The prevalence of malaria parasitaemia was high, affecting 50% of the infants. Having malaria was the only independent predictor associated with stunting, anaemia, and iron-deficiency. There is an urgent need to improve tradi-tional complementary foods in the studied community in terms of energy density, amount of fat in the diet, and bioavailability of macro and micronutrients.

Serum transferrin receptor and zinc protoporphyrin as indicators of iron status in African children

Although transferrin receptor (TfR) and zinc protoporphyrin (ZnPP) are often used to define iron status in school-age children in developing countries, the diagnostic cutoffs for this age group are uncertain. The objective was to determine the sensitivity and specificity of TfR and ZnPP in predicting iron deficiency in black and white children in Africa. Hemoglobin, C-reactive protein (CRP), serum ferritin (SF), TfR, and ZnPP were measured in children in Côte d'Ivoire and Morocco. We excluded children with elevated CRP and then used receiver operating characteristic (ROC) curves to evaluate TfR and ZnPP alone and in combination in screening for iron deficiency, defined as an SF concentration <15 mug/L, and iron deficiency anemia (IDA), defined as an SF concentration <15 mug/L and low hemoglobin. The sample included 2814 children aged 5-15 y. The sensitivity and specificity of TfR and ZnPP were limited by considerable overlap between iron-sufficient, nonanemic children and those with IDA. On the basis of ROC curves, we identified diagnostic cutoffs for TfR and ZnPP that achieved specificities and sensitivities of approximately 60-80%. Separate cutoffs for Côte d'Ivoire and Morocco gave the best performance; the cutoffs for both TfR and ZnPP were higher in Côte d'Ivoire. Moreover, a comparison of nonanemic, iron-sufficient subjects showed that Ivorian children had significantly higher TfR and ZnPP concentrations than did Moroccan children (P < 0.01). New diagnostic cutoffs for TfR and ZnPP, based on ROC curve analyses, may improve the performance of these indexes in defining iron status in children. Significant ethnic differences in TfR and ZnPP suggest that separate cutoffs may be needed for black and white children.

Zinc levels after iron supplementation in patients with chronic kidney disease

Objective The goal of this study was to evaluate the effects of iron supplementation on zinc distribution in nondialyzed chronic kidney disease (CKD) patients. Design Prospective nonrandomized observational study. Setting Outpatients of the Nephrology Division at Federal University of São Paulo. Patients Zinc and iron status of 38 nondialyzed patients (63% male; creatinine clearance, 34.5±13.3 mL/min/1.73 m 2) was evaluated before and after 3 intramuscular injections of 100 mg iron each. Main outcome measures The following parameters were analyzed: erythrocytes and plasma zinc, zinc protoporphyrin (ZPP), plasma ferritin, transferrin saturation (TFS), and total iron. The patients’ diets were analyzed by the Association of Official Analytical Chemists method for macronutrients, and neutron activation analysis was used for iron and zinc concentration determinations. Results Ferritin and TFS increased from 86.3±67.5 ng/mL to 105.4±63.7 ng/mL and from 19.5±7.4% to 23.2±6.7% ( P < .05), respectively, after iron supplementation. Absolute iron deficiency (ferritin <100 μg/L and TFS <20%) was present in 41% of the patients and decreased to 15.7% after iron treatment. In comparison with baseline values (76.4±16.7 μg/dL), there were no significant changes in plasma zinc levels, but after supplementation the number of patients with low plasma zinc levels decreased from 46.1% to 23.7% ( P = .08). At baseline, erythrocyte zinc was 49.0±7.6 μg Zn/gHb, and 76.3% of the patients had high erythrocyte zinc concentration. After iron treatment, erythrocyte zinc decreased to 45.5±7.3 μg Zn/gHb ( P = .001). No significant change was observed in ZPP concentration. The analysis of the diet showed energy and protein intakes of 26.2±7.1 kcal/kg/day and 0.89±0.2 g/kg/day, respectively, and a low intake of both iron and zinc. Conclusions This study suggests that iron deficiency may contribute to the inadequate distribution of zinc in patients with CKD and that iron supplementation may decrease the abnormal elevated erythrocyte zinc levels of these patients.

The protective effect of delta-aminolevulinic acid dehydratase 1-2 and 2-2 isozymes against blood lead with higher hematologic parameters.

Previous studies have suggested that delta-aminolevulinic acid dehydratase (ALAD) types 1-2 or 2-2 are protective against the toxicity of blood lead (PbB) when zinc protoporphyrin (ZPP) levels are low because of differential binding of lead in erythrocytes. The hypothesis is that subjects with the ALAD 1-1 genotype are more susceptible to lead exposure with impaired hematologic synthesis and therefore that iron nutrition is more important in those with the ALAD 1-1 genotype. The purpose of this study was to prove the protective effect of ALAD 1-2/2-2 against PbB with higher hematologic parameters. Data on 1,219 male workers from eight lead-using factories in the Republic of Korea were examined in this cross-sectional study. Blood samples were evaluated for PbB, ZPP, hemoglobin (Hb), and serum iron (SFe) concentrations and ALAD genotypes. The overall prevalence of the ALAD 1-2/2-2 genotype was 9.3%, which was associated with lower log ZPP (p < 0.001) and higher Hb (p = 0.014) levels. For the subjects with normal iron status (SFe levels > 60 micro g/dL), those with the ALAD 1-1 genotype were more likely to be anemic (adjusted odds ratio of 5.2; 95% confidence interval, 1.2-22.6) than those with ALAD 1-2/2-2. The study confirms the protective effects of ALAD 1-2/2-2 polymorphisms against PbB on hematologic pathways. In order to promote health and to minimize the toxicity of lead exposure more effectively, the nutritional management of iron in Korean workers should take both their ALAD genotypes and occupational lead exposures into account.

Dual fortification of salt with iodine and microencapsulated iron: a randomized, double-blind, controlled trial in Moroccan schoolchildren

In many developing countries, children are at high risk of both goiter and iron deficiency anemia. In a series of studies in northern Morocco, we developed and tested a dual-fortified salt (DFS) containing iodine and microencapsulated iron. To establish the DFS fortification concentration, we measured salt intake by 3-d weighed food records and estimated iron bioavailability from the local diet by using published algorithms. We then formulated a DFS containing 25 micro g iodine/g salt (as potassium iodide) and 1 mg iron/g salt (as ferrous sulfate hydrate encapsulated with partially hydrogenated vegetable oil). After storage and acceptability trials, we compared the efficacy of the DFS to that of iodized salt in a 9-mo, randomized, double-blind trial in iodine-deficient, 6-15-y-old children (n = 377). Mean salt intake in school-age children was 7-12 g/d, and estimated iron bioavailability from the local diet was 0.4-4.3%. After storage for 20 wk, the DFS and iodized salt were not significantly different in iodine content, and color stability was acceptable when the compounds were added to local meals. During the efficacy trial, urinary iodine concentrations and thyroid volumes improved significantly (P < 0.001 and < 0.05, respectively) from baseline in both groups. At 40 wk, mean hemoglobin concentrations in the DFS group had increased by 14 g/L (P < 0.01), and serum ferritin, transferrin receptor, and zinc protoporphyrin concentrations were significantly better (P < 0.05) in the DFS group than in the iodized salt group. The prevalence of iron deficiency anemia in the DFS group decreased from 35% at baseline to 8% at 40 wk (P < 0.001). A DFS containing iodine and encapsulated iron can be an effective fortification strategy.

Pediatric reference ranges for zinc protoporphyrin

Objectives To determine pediatric reference ranges for zinc protoporphyrin (ZPP). Design and methods The study was conducted in a large pediatric hospital on patient blood specimens ( n = 6,478) (0–17 y) accrued from January 2001 to June 2002. The data was analyzed employing the Hoffman approach, which was computer adapted. Results and conclusions The 2.5 th and 97.5 th percentiles for children age 0 to 12 months were 9 to 40 μg/dL (16.6–73.6 μmol/mol heme) for female subjects and 8.5 to 34.5 μg/dL (15.6–63.5 μmol/mol heme) for males. The 97.5 th percentiles decreased for the 13 to 24 months age group for females (32 μg/dL) (58.9 μmol/mol heme). There was a significant decrease in the 97.5 th percentile for zinc protoporphyrin (ZPP) concentrations for the 5 to 9 yr age group, the 97.5 th percentile being 30 μg/dL (55.2 μmol/mol heme) in both genders, which increased to 33.5 μg/dL (61.6 μmol/mol heme) in the 10 to 17 yr female age group but not for the males (31.5 μg/dL) (58.0 μmol/mol heme). The highest medians were 25.5 μg/dL (46.9 μmol/mol heme) for females, and 21.5 μg/dL (39.6 μmol/mol heme) for males in the 0 to 12 months age group.

Does iron-deficient erythropoiesis in pregnancy influence fetal iron supply?

It was investigated whether the iron status in newborns is negatively influenced by iron-deficient erythropoiesis of the mother during pregnancy. The iron status is characterized by hemoglobin, erythrocyte zinc protoporphyrin and serum ferritin values. Iron-deficient erythropoiesis of the mother is characterized by erythrocyte zinc protoporphyrin values. Measurement of erythrocyte zinc protoporphyrin was performed in 103 non-anemic females within 24 hours after delivery. The iron status of their newborns was measured in cord blood. Erythrocyte zinc protoporphyrin concentrations were normal in 62% and elevated in 38% of the females, hence 39 women had iron-deficient erythropoiesis. There were no significant differences in mean values of the iron status parameters between neonates born to females with iron-deficient erythropoiesis and neonates born to females not having iron-deficient erythropoiesis. No correlation was found between maternal erythrocyte zinc protoporphyrin values and any of the neonatal parameters. It is concluded that fetal iron supply is not negatively influenced by iron-deficient erythropoiesis in the mother.

Poor Micronutrient Status of Active Pulmonary Tuberculosis Patients in Indonesia

Malnutrition is observed frequently in patients with pulmonary tuberculosis (TB), but their nutritional status, especially of micronutrients, is still poorly documented. The objective of this study was to investigate the nutritional status of patients with active TB compared with that of healthy controls in Jakarta, Indonesia. In a case-control study, 41 out-patients aged 15-55 y with untreated active pulmonary TB were compared with 41 healthy controls selected from neighbors of the patients and matched for age and sex. Cases had clinical and radiographic abnormalities consistent with pulmonary TB and at least two sputum specimens showing acid-fast bacilli. Anthropometric and micronutrient status data were collected. Compared with the controls, TB patients had significantly lower body mass index, skinfold thicknesses (triceps, biceps, subscapular, suprailiac), mid-upper arm circumference, proportion of fat, and concentrations of serum albumin, blood hemoglobin, plasma retinol and plasma zinc, whereas plasma zinc protoporphyrin concentration, as a measure of free erythrocyte protoporphyrin concentration, was greater. When patients and controls were subdivided on the basis of nutritional status, concentrations of serum albumin, blood hemoglobin, and zinc and retinol in plasma were lower in malnourished TB patients than in well-nourished healthy controls, well-nourished TB patients and malnourished healthy controls. In conclusion, the nutritional status of patients with active pulmonary TB was poor compared with healthy subjects, i.e., significantly more patients were anemic and more had low plasma concentrations of retinol and zinc. Low concentrations of hemoglobin, and of retinol and zinc in plasma were more pronounced in malnourished TB patients.

Erythrocyte zinc protoporphyrin testing in pregnancy

To compare the usefulness of serum ferritin, hemoglobin and erythrocyte zinc protoporphyrin estimations as indicators of the need of iron supplementation in pregnancy. In 97 healthy pregnant women serum ferritin, hemoglobin and erythrocyte zinc protoporphyrin concentrations were measured at each trimester period. Iron supplementation was prescribed at hemoglobin values below 113 g/L. Neither in the first nor in the second trimester differences in serum ferritin and erythrocyte zinc protoporphyrin values have been found between women who got iron therapy prescribed and women who did not get iron therapy, whereas already in the first trimester hemoglobin values were lower in the group that got iron therapy. These results indicate that hemodilution rather than iron deficiency determined which women got iron therapy. In the third trimester 14 out of 80 women without iron supplementation had depleted iron stores and a significant erythrocyte zinc protoporphyrin increase, indicating evolving iron deficiency anemia. However, only five of them showed hemoglobin levels below 113 g/L and got iron therapy. Low serum ferritin levels were found in 23% of the women at booking and in 92% in the third trimester. Serum ferritin levels neither predicted the development of iron deficient erythropoiesis nor of anemia. Iron deficiency can neither be diagnosed nor predicted by serum ferritin or hemoglobin measurements at booking or later on in pregnancy. Erythrocyte zinc protoporphyrin measurements can be of help in determining which women have iron deficient erythropoiesis and may benefit by iron therapy.

Erythrocyte protoporphyrins in hepatitis C viral infection

Objectives: Protoporphyrin is the immediate precursor of the heme molecule. Due to a spillover from hemaotopoietic tissue it is regularly found in small amounts in erythrocytes and excreted into the bile. In hereditary erythropoietic protoporphyria excess protoporphyrin accumulates and can cause severe liver damage both by crystallization and induction of oxidative stress. The aim of this investigation was to study protoporphyrin concentrations in other liver disorders. Design and methods: Erythrocyte protoporphyrin and zinc protoporphyrin concentrations were studied in 50 patients with chronic hepatitis C infection and various degrees of liver damage. High-performance liquid chromatographic analysis with fluorescence detection was used. Results: Erythrocyte protoporphyrin was increased in 32% of the patients studied; in 12 patients up to two-fold higher than the maximum of the reference range, in 4 up to three-fold higher (median concentration 98 nmol/L, interquartile range 68–142; maximum 379 nmol/L (reference range: <125 nmol/L)). In 6 of the 10 patients in the subgroup with signs of severe liver dysfunction (decreased serum albumin and prolonged thromboplastin time, elevated serum bilirubin), protoporphyrin was elevated. Erythrocyte zinc protoporphyrin was increased in 7 cases out of all 50 studied; in these seven cases, erythrocyte protoporphyrin was also elevated (median concentration of zinc protoporphyrin in the whole study group: 232 nmol/L, interquartile range 182–342; maximum 827 nmol/L (reference range <464 nmol/L). Conclusions: Elevated erythrocyte protoporphrin levels are frequently found in patients with advanced chronic hepatitis C infection. Because protoporphyrin is well known to be hepatotoxic, these findings warrant further investigation.

Efficacy of d-Penicillamine in Reducing Lead Concentrations in Children: A Prospective, Uncontrolled Study

Objective: To evaluate the efficacy of oral d-penicillamine therapy in children with high blood lead concentrations. Design: A prospective, uncontrolled study. Methods and Patients: Seven children (2–16 y old; mean 8.7) with elevated blood lead concentrations but no symptoms of lead poisoning were treated with oral d-penicillamine. Lead-contaminated homemade flour as found to be the source of poisoning. Mean ± SD blood lead concentrations prior to therapy were 60.3 ± 12.9 μg/dL (range 47.8–83). Mean blood zinc protoporphyrin (ZPP) was 337.86 ± 58.55 μmol/mol hemoglobin (Hb) (range 247–394). Results: Ninety days of treatment with d-penicillamine lowered the mean blood lead concentration by 31.7% to a mean of 40.7 ± 8.6 μg/dL (range 30–53) and lowered mean ZPP blood concentrations by 40% to a mean of 201.14 ± 14 μmol/mol Hb (range 150–278). Three patients with blood lead concentrations &gt;45 μg/mL at the end of this therapy were subsequently treated with succimer, an alternative oral chelator; the blood lead concentrations were further reduced to &lt;45 μg/mL. Conclusions: d-Penicillamine therapy significantly reduced blood lead concentrations but did not achieve acceptable lead and ZPP concentrations for young children. Therefore, we conclude that 90 days of d-penicillamine treatment is of limited effectiveness in young children who have high blood lead concentrations and also show symptoms of lead poisoning.

Serum Transferrin Receptor and Erythrocyte Zinc Protoporphyrin in Patients with Anemia

The conventional laboratory test for diagnosing iron deficiency anemia (IDA) is the measurement of serum ferritin. In healthy persons, serum ferritin is directly proportional to body iron stores. In the presence of anemia, a value <20 μg/L is regarded as evidence of IDA (1). In patients with anemia of chronic disease (ACD), an increase in serum ferritin, unrelated to iron storage status, occurs. Serum ferritin concentrations usually exceed 100 μg/L when iron stores are adequate, but they may still be within the reference interval in the presence of coexisting iron deficiency (1). The assay lacks sensitivity in diagnosing IDA in patients with ACD, as well as in patients with acute infections and with liver diseases. The best established method for evaluating iron stores is examination of bone marrow iron, but this test is cumbersome and expensive. Since the early 1970s, measurement of the zinc protoporphyrin concentration (ZPP) in erythrocytes has been used as test for iron deficiency. When there is insufficient iron for incorporation into protoporphyrin IX to form heme, ZPP increases, indicating iron-deficient erythropoiesis (2). Most authors have reported a high sensitivity in diagnosing IDA, irrespective of the presence of complicating diseases (3)(4)(5). However, disturbed incorporation of iron into protoporphyrin IX can also occur in other diseases, such as ACD, hemolytic anemias, bone marrow diseases, and lead intoxication. The specificity of ZPP in diagnosing IDA is limited (6)(7). In recent years, the measurement of soluble transferrin receptor (sTfR) fragments has been introduced for the identification of iron deficiency (8). The concentration of sTfR is directly proportional to the number of red cell precursors. An exception to this rule is in patients with IDA. A reduction in iron supply leads to up-regulation of transferrin receptor synthesis, producing an increase in sTfR concentration. Several …

Indicators of erythrocyte formation and degradation in rats with either vitamin A or iron deficiency

Vitamin A deficiency produces anemia and altered iron status. In this study with rats we tested two hypotheses regarding vitamin A deficiency: (1) that it impairs erythropoiesis, leading to an increased red cell turnover, and (2) that it inhibits the glycosylation of transferrin. Erythropoietic activity was assessed indirectly by determining the myeloid:erythroid ratio in bone marrow smears, the number of erythroid colonies in the red pulp of spleen, the blood reticulocyte index, and zinc protoporphyrin and plasma transferrin receptor concentrations. Transferrin glycosylation was assessed by measuring the sialic acid content of transferrin. The effects of vitamin A deficiency were compared with those of iron deficiency. Iron deficiency produced anemia and low iron levels in organs. Vitamin A deficiency produced low levels of plasma and hepatic retinol, and it induced decreased plasma total iron-binding capacity and raised iron levels in tibia and spleen. Short- but not long-term iron deficiency reduced the number of erythroid colonies in spleen; vitamin A deficiency had no influence. Neither iron nor vitamin A deficiency influenced the myeloid:erythroid ratio in bone marrow smears and the blood reticulocyte production. Plasma transferrin receptor and erythrocyte zinc protoporphyrin concentrations were not affected by vitamin A deficiency but increased with iron deficiency. Vitamin A deficiency did not stimulate erythrocyte breakdown, as indicated by unaltered plasma lactate dehydrogenase activity and reduced plasma total bilirubin levels. Both vitamin A and iron deficiencies raised the proportion of multiple sialylated transferrins in plasma. Thus, we have not found evidence that vitamin A deficiency affects erythropoiesis and erythrocyte turnover. The iron accumulation in spleen and bone marrow may be related to reduced iron transport due to inhibition of transferrin synthesis rather than inhibition of transferrin sialylation.

Zinc protoporphyrin IX concentrations between normal adults and the lead-exposed workers measured by HPLC, spectrofluorometer, and hematofluorometer.

To establish the relationship between Zinc protoporphyrin (ZPP) concentrations and blood lead (PbB) levels and to identify reliable analytical methods of ZPP and Protoporhyrin (PP), blood samples were obtained from 263 office workers without the history of occupational lead exposure and 49 lead-acid battery workers. The mean concentrations of PbB for the normal adults and the battery workers were 9.26 microg/dl and 42.60 microg/dl, respectively. The geometric mean concentrations of ZPP and PP by HPLC were 18.73 microg/dl and 2.27 microg/dl for normal adults and were 46.99 microg/dl and 5.53 microg/dl for the exposed workers, respectively. The geometric mean concentrations of ZPP and PP by a spectrofluorometer (SF) were 30.27 microg/dl and 5.16 microg/dl for normal adults and were 50.91 microg/dl and 6.69 +/- 1.39 microg/dl for the exposed workers. The geometric mean ZPP concentration measured by a hematofluorometer (HF) was 30.88 microg/dl for normal adults. The results showed that ZPP concentrations measured by HF were consistently higher than those by HPLC and SF for normal adults, and lower for the exposed workers. ZPP concentrations were not correlated with PbB levels for normal adults but a statistically significant correlation was found among the exposed workers.

Blood Lead Concentration and Biological Effects in Workers Exposed to Very Low Lead Levels

A longitudinal study was carried out on two groups of workers engaged in tin/lead alloy welding in the telecommunication sector. The risk of exposure was evaluated by measuring levels of airborne lead (PbA) and the amount of lead absorbed (PbB). The-correlated effects were assessed by determining zinc protoporphyrin (ZPP) and hemoglobin levels (Hb) and red blood cell (RBC) count. We also recorded subjective symptoms reported by workers. One group of welders composed of 365 subjects underwent two monitoring sessions performed in 1991 and 1995, respectively (Group A). A second group of welders (whose number fluctuated between 148 and 247 subjects) underwent yearly testing for 7 consecutive years (1988-1994; Group B). Results indicated a very low risk of lead exposure during microwelding operations (PbA range, 1.5-24 micrograms/m3). In fact, blood concentrations of Pb (range, 5-55, micrograms/dL) among both groups of welders were significantly higher than those in the general population in Rome (PbB range, 5-16 micrograms/dL); nevertheless, they were significantly lower than the Occupational Safety and Health Administration's permissible exposure limits ZPP determined only in Group B of welders ranged from 5 to 16 micrograms/dL (median, 22 micrograms/dL). No variation was found in the other biological parameters investigated, and no health effects were observed. During the study period, the introduction of some technological innovations led to a further reduction in Pb exposure and, subsequently, to its total elimination. PbB concentrations gradually declined to lower values (6-36 micrograms/dL), and it was interesting to note that ZPP concentrations also decreased to normal levels (range, 2-47 micrograms/dL; median, 11 micrograms/dL), demonstrating that the effect of lead on heme synthesis may occur even at very low levels of Pb exposure.

Assessment of Lead Exposure in Schoolchildren from Jakarta

Children attending schools in urban areas with high traffic density are a high risk group for lead poisoning. We assessed the magnitude of lead exposure in schoolchildren from Jakarta by analyzing blood lead concentrations and biomarkers of heme biosynthesis. A total of 131 children from four public elementary schools in Jakarta (two in the southern district and two in the central district) were enrolled in the study. To evaluate lead pollution in each area, soil samples and tap water were collected. The mean blood lead concentration was higher in the central district than in the southern district (8.3 +/- 2.8 vs. 6.9 +/- 3.5 microg/100 ml; p<0.05); 26.7% of the children had lead levels greater than 10 microg/100 ml. In 24% of the children, zinc protoporphyrin concentrations were over 70 micromol/mol hemoglobin; in 17% of the samples, hemoglobin was less than 11 g/100 ml. All other values were within the physiological range. Blood lead concentration and hematological biomarkers were not correlated. Analyses of tap water revealed lead values under 0. 01 mg/l; lead contamination of soil ranged from 77 to 223 ppm. Our data indicate that Indonesian children living in urban areas are at increased risk for blood lead levels above the actual acceptable limit. Activities to reduce pollution (e.g., reduction of lead in gasoline) and continuous monitoring of lead exposure are strongly recommended.

Predictive value of determinations of zinc protoporphyrin for increased blood lead concentrations

Blood lead (PbB) and red cell zinc protoporphyrin (ZPP) concentrations are widely used biomarkers for lead toxicity. It is uncertain, however, whether either or both are needed for monitoring lead exposure and how discordant PbB and ZPP values should be interpreted. We reviewed the results of PbB and ZPP determinations in 94 workers in a lead-battery plant over a 13-year period and retrieved all 807 sets of tests in which both PbB and ZPP were available, with a follow-up PbB value 6 months later. PbB exceeded 1.93 micromol/L (40 microg/dL) in 414 (51%), and 2.90 micromol/L (60 microg/dL) in 105 (14%) of the blood samples. We derived the test properties of various ZPP concentrations for concurrent "toxic" PbB concentrations, defined as > or = 1.93 and 2.90 micromol/L (40 and 60 microg/dL). The results indicated that, given a population of lead-exposed workers with a 10% prevalence of PbB of > or = 2.90 micromol/L (60 microg/dL), a policy of testing PbB only in those with ZPP > 0.71 micromol/L (40 microg/dL) would obviate 42% of the PbB tests, but would miss about three cases with toxic PbB concentrations in every 200 workers at risk. A finding of increased ZPP concentrations with a concurrent "nontoxic" PbB was associated with an increased risk of a toxic PbB concentration 6 months later. We conclude that (a) screening by testing only ZPP does not safeguard exposed persons against lead toxicity, and (b) the frequency of PbB monitoring should be guided by estimates of the risk of future lead toxicity in individual workers.

Blood Lead and ZPP Concentrations of Underground Parking Lot Workers

A study was conducted to investigate the blood lead and zinc protoporphyrin(ZPP) concentrations of the underground parking lot workers who exposed to vehicular exhaust aerosols which contained lead. The blood samples were collected from 25 study subjects of underground parking lot and from 33 controls in Taegu, from July to October, 1997. And also the related factors to the blood lead and ZPP concentrations were investigated. Blood lead concentration and ZPP concentration were measured by flameless furnace atomic absorption spectrophotometer (1L.551) and hemetofluorometer, respectively. The mean blood lead concentrations of study subjects and controls were and , respectively(p and , respectively. No significant correlations were observed between the blood lead concentration of the study subjects and their job duration and between blood ZPP concentration of the study subjects and their job duration. There were no statistically significant differences in the blood lead concentration and the blood ZPP concentration of smokers and nonsmokers. In multiple regression analysis on blood lead concentration of the study subjects and controls, occupation was a only significant dependent variable. In case of bood ZPP concentration, age was a only significant dependent variable in the study subjects and controls.

Serum Calmodulin Activity in Male Lead-exposed Workers.

Serum calmodulin (CaM) activity was studied in 75 lead-exposed and 21 non-exposed male workers. The lead-exposed workers were divided into groups with low blood lead (BPb < 50 µg/dL) and high blood lead (BPb>/=50 µg/dL). The concentrations of lead, calcium, magnesium, copper, zinc, and free erythrocytic protoporphyrin (FEP) in blood were determined. Serum samples were heated in a water bath (100 degrees C) for 3 minutes and centrifuged for 15 minutes at 4 degrees C (18,000 x g). The supernatants obtained were used to measure CaM activity. The results showed that: 1) Average blood lead concentrations in workers with both low and high levels of exposure were significantly higher than those in controls (p < 0.05). 2) Serum CaM activity in the high-exposure group (31.09 +/- 7.84 µg/dL) was significantly lower than that in controls (78.11 +/- 15.13 µg/dL, p < 0.05). The biological threshold of BPb inhibition of CaM activity was less than 50 µg/dL. 3) Multiple correlation analysis showed a negative dose-response relationship between BPb and CaM activity. The stepwise regression procedure indicated that lead had negative, and calcium and magnesium positive, effects on serum CaM activity. The regression equation was Y = 66.1383 - 1.0857 X&inf1; + 2.9676 X&inf2; + 5.2222 X&inf3; (Y:CaM; X&inf1;:Pb; X&inf2;: Ca; X&inf3;:Mg). These results of the first such study carried out in male lead-exposed workers suggest that lead can inhibit CaM activity in humans.