Low-Dose Pesticide Mixture Induces Senescence in Normal Mesenchymal Stem Cells (MSC) and Promotes Tumorigenic Phenotype in Premalignant MSC.

Humans are chronically exposed to multiple environmental pollutants such as pesticides with no significant evidence about the safety of such poly-exposures. We exposed mesenchymal stem cells (MSC) to very low doses of mixture of seven pesticides frequently detected in food samples for 21 days in vitro. We observed a permanent phenotype modification with a specific induction of an oxidative stress-related senescence. Pesticide mixture also induced a shift in MSC differentiation towards adipogenesis but did not initiate a tumorigenic transformation. In modified MSC in which a premalignant phenotype was induced, the exposure to pesticide mixture promoted tumorigenic phenotype both in vitro and in vivo after cell implantation, in all nude mice. Our results suggest that a common combination of pesticides can induce a premature ageing of adult MSC, and as such could accelerate age-related diseases. Exposure to pesticide mixture may also promote the tumorigenic transformation in a predisposed stromal environment. Abstract Video Link: https://youtu.be/mfSVPTol-Gk Stem Cells 2017;35:800-811.

Ultrastructural study of liver and lead tissue concentrations in young mallard ducks (Anas platyrhynchos) after ingestion of single lead shot.

Lead (Pb) represents a serious threat to wildlife and ecosystems. The aim of this study was to examine the subcellular effects of dietary Pb pellet ingestion on mallard (Anas platyrhynchos) livers. After ingestion of a single Pb shot (LS4 size class: 0.177 ± 0.03 g) in 41 mallard ducks (22 males and 19 females) versus 10 controls (5 males and 5 females), all 7-week old, a morphologic study was conducted by TEM (transmission electron microscopy) of liver at the subcellular level. The results in treated mallards showed at a magnification of 2500 X that hepatic parenchyma was altered as evidenced by intralysosomal electron-dense deposits, which are compatible with Pb deposits. Further, at a higher magnification (15,000 X) in both genders, deterioration of mitochondria was observed in which the crests and, to a lesser extent, outer membrane were lysed. While the rough endoplasmic reticulum was fragmented, intracytoplasmic electron-dense material compatible with Pb deposits was maximally visible, thereby underscoring the deeply destructive effect of this metal on the subcellular architecture of the liver. In addition, applying an optimized and validated method in a clean room using electrothermal atomic absorption spectrophotometer (ETAAS) with Zeeman background correction, the objective was to improve and refine certain indispensable measurements pertaining to Pb impregnation in tissues other than liver such as kidneys, bones, and feathers of mallards. Data demonstrated show that compared with controls, Pb accumulation increases significantly, not only in the liver (3-fold), but also in the bones and the feathers (14-fold). No significant difference was noted between males and females. Bearing in mind the marked subcellular toxicity attributed to Pb, this study reinforces present-day arguments advocating limitation of game consumption.

Comparison Between an Automated and Manual Extraction for the Determination of Immunosuppressive Drugs Whole Blood Concentrations by Liquid Chromatography Tandem Mass Spectrometry.

BACKGROUND: The whole blood extraction for liquid chromatography tandem mass spectrometry (LC-MS/MS) of simultaneous quantification of cyclosporine A (Cys A), tacrolimus (Tacrs), sirolimus (Siros), and everolimus (Evers) is still performed manually in many laboratories. The analytical results obtained with an automated method using a liquid handler versus a classical manual preparation were compared. METHODS: Cys A (n = 36), Tacrs (n = 50), Siros (n = 34), Evers (n = 38) whole blood samples of patients were analyzed by LC-MS/MS assay after manual preparation and automated process using a liquid handling platform including a centrifugation step. RESULTS: The comparison between manual and automated extraction investigated by a linear regression showed a high correlation between results [(Tacrs "automated") = 1.0927 × (Tacrs "manual") - 0.36; (Cys A "automated") = 1.0284 × (Cys A "manual") + 0.0312; (Siros "automated") = 0.9923 × (Siros "manual") + 0.4001; (Evers "automated") = 1.0000 × (Evers "manual") - 0.0600]. CONCLUSION: The results obtained by the automated and manual preparation are consistent. The automated method is applied for high-throughput therapeutic drug monitoring of immunosuppressive drugs in routine practice, leading to an increase in quality.

Interlaboratory comparison study on lead in blood, in external quality assessment schemes since 1996: a progress report.

In 1992, at the request of the French labor ministry, an External Quality Control for lead in whole blood (F-EQCPbB) came into being. After 15 years (1996-2011), the ministry wished to exploit the database collected with a sufficient number of laboratories. Indeed, the number of participating laboratories had decreased from 73 to 41. However, the key finding pertained to the highly improved performance of the laboratories, which was associated with a spread of the results over the entire range of tested PbB (9 and 700 µg/l). So, it was that in laboratories having participated for >10 years, the good scores rose between 1996 and 2011 from 49% to 93%. To sum up, analysis has shown progressive and highly pronounced diminution of CVs (%) for all the ranges having undergone testing. We have observed increasing use of inductively coupled plasma with mass spectrometry (from 9% in 2005 to 29% in 2011) and decreasing use of electrothermal atomic absorption spectrometry. That said, and provided that they are based on the same degree of expertise in metrology, on all tested concentrations the two analytical techniques yield results that are not statistically different. Thanks to the F-EQCPbB, laboratories have enhanced their proficiency and registered demonstrably improved performance.

Hair Trace Elements and Mineral Content in Moroccan Children with Autism Spectrum Disorder: a Case-Control Study.

The prevalence of autism spectrum disorder (ASD) around the world continues to increase while the pathophysiology remains insufficiently elucidated. Genetics, environment, and epigenetic changes are often implicated. Abnormal level in trace elements and minerals is among environmental factors assumed to be involved. The purpose of this article is to assess hair concentrations of toxic and essential elements in children with ASD and children with neurotypical development in the city of Marrakech. Two hundred and twenty-seven children (107 with ASD and 120 controls) aged 3 to 14 years old were recruited. The results of analysis by ICP-MS showed a significant decrease in hair levels of copper, zinc, iron, and selenium (25%, 13%, 17%, 11%) of children with ASD. The most significantly reduced concentrations in children with ASD are that of manganese by 34%. Hair aluminum level was significantly elevated by 29% in ASD compared to controls. Multiple linear regression analysis revealed that copper, selenium, and iron content in hair were significantly inversely associated with ASD, similarly, hair aluminum content was significantly associated with ASD. Adjusted model for demographic parameters increased the predictive ability of the model, father's age was a significant predictor. In addition, ASD and gender were significant predictors of hair levels of aluminum, selenium, and manganese.These results support the hypothesis of the disparity of trace elements and minerals levels in children with ASD and highlight the potential interest of micronutrient supplementation in the eventual improvement of ASD symptoms. Future research should explore the pathophysiology of these micronutrient deficiencies.

An analytical procedure for the determination of aluminum used in antiperspirants on human skin in Franz™ diffusion cell.

A local case report of hyperaluminemia (aluminum concentration: 3.88 µmol/L) in a woman using an aluminum-containing antiperspirant for 4 years raises the question of possible transdermal uptake of aluminum salt as a future public health problem. Prior to studying the transdermal uptake of three commercialized cosmetic formulas, an analytical assay of aluminum (Al) in chlorohydrate form (ACH) by Zeeman Electrothermal Atomic Absorption Spectrophotometer (ZEAAS) in a clean room was optimized and validated. This analysis was performed with different media on human skin using a Franz(™) diffusion cell. The detection and quantification limits were set at ≤ 3 µg/L. Precision analysis as within-run (n = 12) and between-run (n = 15-68 days) yield CV ≤ 6%. The high analytic sensitivity (2-3 µg/L) and low variability should allow an in vitro study of the transdermal uptake of ACH.

Copper acetate aerosols: A possible tool complementary to vaccination in fight against SARS-CoV-2 and variants replication.

In SARS-CoV-2, at the S1/S2 furin cleavage site, a four amino acid insert (P-R-R-A) not found in closely related corona viruses, has been shown to facilitate entry into respiratory epithelial cells and promote virus transmission, infectivity and virulence. By cupric aerosol treatment, complexation of these four amino acids (-P-R-R-A-), at the spike (S) protein site will lead to a conformational change possibly impeding SARS-CoV-2 replication process in the respiratory track. Since these four amino acids yield strong and stable copper complexes, subsequent to a steric hindrance, this complexation will disturb the furin-like protease cleavage at the spike protein site as it has been recently shown in vitro with copper gluconate. The compilation of stability constants for copper amino-acid complex formation, showing values of the same order of magnitude for all the twenty proteinogenic amino-acids demonstrate thermodynamically that copper amino-acid chelation for SARS-CoV-2 virus will not be affected by mutations leading to amino acid exchanges in the spike protein region. Given its low toxicity, and its very low stability formation constant, copper acetate is proposed rather than copper gluconate for possible cupric aerosol or nasal spray treatments aimed at impeding SARS-CoV-2 multiplication. It will open different medical perspectives, complementary to vaccination, in the fight against COVID 19 native virus, variants and future mutants.

Is There Correlation Between Aluminum-Based Food Consumption and Plasma Level in Pregnant Women?

To explore the correlation of AL-based food consumption, known to have negative impact on health, and Al plasma levels with pregnancy status. A cross-sectional study was conducted on 75 participants, including 50 pregnant women. Al plasma levels were analyzed by ET-AAS. Exposure to food was positively correlated to Al mean plasma levels (reaching 2.12 ± 1.17 µg/L) by 32%, specifically for potatoes, fruits, soft drinks, and ready meals. Usage of Al cookware was associated to higher Al plasma levels while pregnancy status was protective. Establishment of national recommendation to maintain lower levels of Al in food is required.

Iron deficiency and cognitive impairment in children with low blood lead levels.

Background: The relationship between iron deficiency (ID) and children's neurocognitive functions has attracted the interest of the scientific community, particularly among those living at the lead-contaminated sites. Thus, the current paper aims at evaluating the association between ID and neurocognitive performance of school children living in a mining area (CMA) in comparison with a control group (CG). Methods: he study involves 90 school children aged from 6 to 10 years old. A survey was conducted to obtain information on the socio-economic and demographic status of the children. The students underwent cognitive test battery including the Bell Dam Test (BDT) and the Digit Span test (DST). Iron status (IS) was determined by serum iron, ferritin, transferrin, and blood count (CBC). Blood lead levels (BLLs) were measured by the Graphite Furnace Atomic Absorption Spectrophotometer (SAA-FG). Results: An ID was observed in 23.3 % of CMA, but it is not statistically different from the CG 21.7 % (p = 0.774). CMA group exhibited elevated BLLs (3.5 ± 1.21 µg/dL) when compared to the CG (2.31 ± 0.95 µg/dL), p = 0.006. Children's performance on the visual attention test (VA) was impaired in both groups. Working memory (WM) abilities were normal. In bivariate analysis, no difference was demonstrated in mean BLLs between the students who adopt the disorganized scanning strategy compared to the others whose method is organized for both CMA (t = - 0.508, p = 0.616) and CG (t = - 0.014, p = 0.989). Multivariate models did not reveal any association between IS and cognitive scores of children in the two groups (p > 005). Nevertheless, daily milk consumption was positively associated to VA skills among CMA. A negative influence of BLLs above the threshold value of 5 µg/dL was determined on children's WM skills. Conclusion: Our results suggest that low-level lead exposure did not influence children's visual attention scores but may adversely affect WM abilities if it reaches the threshold value of 5 µg/dL regardless of their IS.

Aluminum exposure from food in the population of Lebanon.

Widely used for a variety of applications, levels of dietary aluminum (Al) have seen a perpetual rise in Lebanon, leading to noticeable effects upon the human body. This study aims to estimate the rates of Al contaminated food consumption and quantify the Al present in different dietary matrices, revealing the major contributors to Al exposure for the Lebanese population. A cross-sectional study was conducted using a customized, self-reported Electronic Food Frequency Questionnaire (E-FFQ) using Curve®, targeting individuals between the ages of 18 and 64 from different Lebanese regions, distributed proportionally. The selection of food was based upon the results of the French EAT2 study. Al levels in food were analyzed using Flame Atomic Absorption Spectrometry (FAAS) after acid digestion. The E-FFQ was completed by 167 respondents. Data analysis was performed on SPSS version 25. Additionally, 97 food items were studied in 2018. Al levels had a mean of 3.56 ± 2.08 mg/kg (ranging from 0.14 to 9.37). The highest Al levels were found in vegetables, followed by sauces and condiments, candies, and ready meals. The Provisional Tolerable Weekly Intake (PTWI) of Al was set at 0.50 mg/kg body weight (60 Kg/person). Al mean Daily Dietary Exposure (DDE) was estimated to be 4341.18 µg/day, with the highest food exposure coming from lettuce, soft drinks, ice cream and tea. Al ingestion rates for the adult Lebanese population does not exceed the international established thresholds of tolerable intake (1 mg/kg/week). National recommendation should be developed to control the presence of metal for food safety purposes.

High prevalence of kaolin consumption in migrant women living in a major urban area of France: A cross-sectional investigation.

Geophagia is a feeding behavior involving the regular intake of soil, including clay-like kaolin. Frequent in Africa, kaolin consumption is associated with heavy metal intoxication, iron and other micronutrient deficiencies, geohelminth infection and inactivation of concomitantly taken drugs. It is expected that this practice would be imported into an asylum country during the immigration process. To confirm this hypothesis, a single center, cross-sectional study was conducted at the University Hospital of Nantes, France, whose main objective was to assess whether the prevalence of kaolin consumers was high in a migrant population living in a large French metropolitan area (the city of Nantes). Each woman consulting for the first time at the Medical and Psychosocial Gynecology Obstetric Unit during the inclusion period ranging from January 1, 2017, to July 1, 2017, was asked for consent to be included in the study. The main outcome was the proportion of positive answers regarding consumption of kaolin within the last twelve months, with its 95% confidence interval (CI). A logistic regression was performed to identify drivers of consumption, and a clustering approach was conducted to identify profiles of consumers. A total of 284 women were included in the study, of whom 110 (38.7%) were pregnant. Our main finding was a 14.1% (95% CI: 10.5-18.6) prevalence of clay consumers. Second, the characteristic most strongly associated with consumption was Central or West Africa origin (adjusted Odds Ratio (aOR) = 52.7; 95% CI: 13.7-202.2). Finally, 60% of consumers showed signs of addictive-like phenomena, and three profiles were identified, depicting a continuum of patients in regard to their control over their kaolin consumption. Our results suggest that kaolin consumption is frequent in particular subpopulations of migrants. This warrants further study of the clinical consequences of kaolin consumption and its associated addictive-like symptoms.

Original triazine inductor of new specific molecular targets, with antitumor activity against nonsmall cell lung cancer.

Despite our growing insight into carcinogenesis, treatment of tumors, especially nonsmall cell lung cancer (NSCLC), remains limited and it is urgent to develop strategies that target tumor cells and their genetic features. Drug discovery efforts have historically focused on the search for compounds that modulate the protein products of genes. Current drug therapy targets only a few hundred endogenous targets, mainly proteins, such as receptors and enzymes. But now, the interest in specifically targeting RNA is increasing, both for target validation and/or therapeutic purposes. In this regard, our work was concerned with the induction of new molecular targets correlated to a cytostatic effect on NSCLC cell line, after treatment with a new triazin named A190. The in vitro study of cell cycle and apoptosis induction demonstrated the antiproliferative potential of this new compounds, and the use of quantitative RT-PCR analysis permit to display an original mechanism of action involving 2 genes: HEF1 and B2. The antitumor effect was also confirmed by the good results in vivo on nude mice xenografts.

Copper brain protein protection against free radical-induced neuronal death: Survival ratio in SH-SY5Y neuroblastoma cell cultures.

In Creutzfeldt Jakob, Alzheimer and Parkinson diseases, copper metalloproteins such as prion, amyloid protein precursor and α-synuclein are able to protect against free radicals by reduction from cupric Cu+2 to cupreous Cu+. In these pathologies, a regional copper (Cu) brain decrease correlated with an iron, zinc or manganese (Mn) increase has previously been observed, leading to local neuronal death and abnormal deposition of these metalloproteins in ß-sheet structures. In this study we demonstrate the protective effect of Cu metalloproteins against deleterious free-radical effects. With neuroblastoma SH-SY5Y cell cultures, we show that bovine brain prion protein in Cu but not Mn form prevents free radical-induced neuronal death. The survival ratio of SH-SY5Y cells has been measured after UV irradiation (free radical production), when the incubating medium is supplemented with bovine brain homogenate in native, Cu or Mn forms. This ratio, about 28% without any addition or with bovine brain protein added in Mn form, increases by as much as 54.73% with addition to the culture medium of native bovine brain protein and by as much as 95.95% if the addition is carried out in cupric form. This protective effect of brain copper protein against free radical-induced neuronal death has been confirmed with Inductively Coupled Plasma Mass Spectrometry Mn and Cu measurement in bovine brain homogenates: respectively lower than detection limit and 9.01µg/g dry weight for native form; lower than detection limit and 825.85µg/g dry weight for Cu-supplemented form and 1.75 and 68.1µg/g dry weight in Mn-supplemented brain homogenate.

A Squalene-Based Nanomedicine for Oral Treatment of Colon Cancer.

Nanotechnology offers many possibilities to improve drug treatments, including with regard to drug pharmacology. The current study reports a simple approach to improve cisplatin efficacy in the treatment of colon cancer through the creation of orally administered squalenoylated nanoparticles loaded with cisplatin (SQ-CDDP NP). Cytotoxic effects of SQ-CDDP NP were assessed in human colonic cells and in mouse models of intestinal cancer. In cell culture, SQ-CDDP NP exhibited at least 10-fold greater cytotoxic potency compared with uncomplexed cisplatin, reflecting an enhancement in intracellular accumulation and DNA platination. Mechanistic investigations showed that SQ-CDDP NP stimulated ROS production, expression of heavy metal-inducible and stress-inducible genes, stress kinase cascades, and apoptosis. In ApcMin/+ mice, a model of intestinal tumorigenesis, oral administration of SQ-CDDP NP curtailed spontaneous tumor formation and azoxymethane-induced colon carcinogenesis with no apparent evidence of tissue toxicity. Our results offer preclinical validation of a nanocarrier formulation that can safely improve chemotherapeutic efficacy, address risks of drug resistance, and improve patient compliance by enabling oral administration. Cancer Res; 77(11); 2964-75. ©2017 AACR.

Filling of carbon nanotubes with selenium by vapor phase process.

A vapor phase method was developed to fill different kinds of nanotubes (including multiwall and singlewall nanotubes), which inner diameters range from 200 down to 1.5 nm. Experiments were performed with selenium in a sealed reactor in order to control the selenium partial pressure. This process allows a full control of the nanotube filling (partial or complete), i.e., either a selective diameter filling or a full filling rate. The weight gain of all the samples was plotted for different reaction temperature as a function of selenium pressure. Experimental isotherms are characteristic of capillary condensation of selenium, which occurs at first in the smallest nanotube inner diameters. X-ray diffraction data show that selenium confined in nanotubes with diameters larger than 3 nm keeps its trigonal structure.

Effects of Imbalance in Trace Element on Thyroid Gland from Moroccan Children.

The major environmental factor that determines goiter prevalence is iodine status. However, other trace elements like selenium and zinc can influence the thyroid function. Hair samples (n = 68) were collected from goitrous and non-goitrous children aged 8-12 years living in the area of Al Haouz Marrakech-(Morocco). Trace element concentrations (Cr, Fe, Mg, Zn, Se, I) in hair were measured using flame atomic absorption spectroscopy, graphite furnace atomic absorption spectroscopy, and inductively coupled plasma mass spectrometry. Difference in the mean concentration of each trace element between groups was determined by ANOVA test. The mean concentration levels of I, Se, and Zn for goitrous children were lower and were similar to the mean concentrations reported in the literature for subjects with goiter. The regression results gave us a better model that revealed significant positive relations between thyroid volume and Zn contents and significant negative relation with I and Se. The overall findings of the present study revealed that the actual factors of thyroid gland volume increase are I and Se deficiency. This work could shed some light on the effects of trace elements-other than iodine-on the thyroid disorders.

Evaluation of a Methotrexate Chemiluminescent Microparticle Immunoassay: Comparison to Fluorescence Polarization Immunoassay and Liquid Chromatography-Tandem Mass Spectrometry.

OBJECTIVES: For most laboratories, methotrexate (MTX) concentrations are routinely monitored by fluorescence polarization immunoassay (FPIA). In anticipation of an announced withdrawal of the FPIA reagent on the Abbott TDxFLx (Abbott Diagnostics, Abbott Park, IL), we have evaluated a new reagent kit developed by Abbott on the Architect i1000, based on chemiluminescent microparticle immunoassay (CMIA). METHODS: Precision, inaccuracy, and selectivity were assessed. Interassay variability was established using 75 plasma patient samples treated with MTX and analyzed by two methods: FPIA and liquid chromatography-tandem mass spectrometry (LC-MS/MS). RESULTS FOR MTX,: the intraday inaccuracy was between -6.37% and +3.52%, while interday performance was between -3.70% and 7.90%. Intraday and interday imprecision was less than 2.65% and less than 2.22%, respectively. The correlation coefficient between CMIA and FPIA or LC-MS/MS was 0.9969 and 0.9985, respectively. CONCLUSIONS: These results comparing CMIA vs FPIA and LC-MS/MS indicate that CMIA is a suitable alternative to the FPIA method.

Stability and Compatibility of Antibiotics in Peritoneal Dialysis Solutions Applied to Automated Peritoneal Dialysis in The Pediatric Population.

♦ OBJECTIVES: Assess the stability of several antibiotics in peritoneal dialysis (PD) solutions under common conditions of use in pediatrics, particularly in automated PD. ♦ METHODS: Amoxicillin, cefazolin, cefepime, ceftazidime, imipenem, cotrimoxazole, tobramycin, vancomycin, and the association of ceftazidime + vancomycin and ceftazidime + tobramycin, were tested in 3 different PD solutions: bicarbonate/lactate solution with 2 glucose concentrations (Physioneal 1.36 and 3.86%; Baxter Healthcare Corporation, Deerfield, IL, USA) and an icodextrin-containing solution (Extraneal; Baxter Healthcare Corporation, Deerfield, IL, USA). Concentrations were those recommended in guidelines for the treatment of peritonitis in pediatrics. Physioneal bags were incubated at 37°C for 24 hours, whereas Extraneal bags were stored 12 hours at room temperature (22 ± 2°C) and then 12 hours at 37°C. Drug concentrations were determined using high performance liquid chromatography (HPLC). Each measure was taken in triplicate. Stability of antibiotics was defined as less than 10% degradation of the drug over time. ♦ RESULTS: Cefazolin, cotrimoxazole, tobramycin, and vancomycin were stable under studied conditions. Ceftazidime was stable 24 hours in icodextrin, 12 hours in Physioneal 1.36% and 6 hours in Physioneal 3.86%. The association of tobramycin or vancomycin did not influence the stability of ceftazidime. Cefepime and amoxicillin were stable 6 h, 4 h, and 8 h in Physioneal 1.36%, 3.86% and Extraneal, respectively. The stability of imipenem was very low: 2 h in Physioneal and 6 h in Extraneal. Moreover, an increasingly yellow coloration was observed with the use of imipenem, whereas no color change or precipitation occurred in other bags. ♦ CONCLUSION: Cefazolin, tobramycin, cotrimoxazole, and vancomycin are stable in PD solutions up to 24 hours and can be administered in the PD bag for the treatment of peritonitis, even in automated PD under studied conditions. However, amoxicillin, cefepime, ceftazidime, and imipenem must be used with caution due to their lack of stability.

Optimisation of Direct Copper Determination in Human Breast Milk Without Digestion by Zeeman Graphite Furnace Atomic Absorption Spectrophotometry with Two Chemical Modifiers.

Milk is an important food in the human diet, and copper (Cu) in human milk is indispensable to children's normal growth and development. It is consequently important that Cu deficiency, occurring in malnourished women or in malabsorption following bariatric surgery, be prevented. The objective of this work is to provide hospital-based paediatricians with a tool enabling rapid measurement of Cu in human breast milk through a technique that biology laboratories can easily apply. Using electrothermal atomic absorption spectrophotometry with Zeeman correction, we have optimized this method with two chemical modifiers and without digestion for analytical procedure. Detection limits and quantification limits for Cu in human milk were found to be 0.077 and 0.26 µmol/L, respectively. Within-run (n = 30) and between-run (n = 15) variations in a pool of human milk samples were 1.50 and 3.62%, respectively. Average recoveries ranged from 98.67 to 100.61%. The reliability of this method was also confirmed by analysing certified reference material (10%). In breast milk samples collected from 100 lactating mothers, Cu mean (±1 SD) was 7.09 ± 1.60 µmol/L. In conclusion, with minimal preparation and quick determination, the method proposed is suitable for measurement of Cu in human breast milk.

Determination of lead in whole blood: comparison of the LeadCare blood lead testing system with Zeeman longitudinal electrothermal atomic absorption spectrometry.

This study compares the efficiency of blood lead level analysis by graphite furnace atomic absorption spectrometry (GFAAS) and the portable LeadCare Blood Lead Testing System (LCS). Recoveries of two added lead concentrations of 22 and 42 micrograms/dL ranged from 102.4 to 105.5% for LCS and from 96.3 to 97.2% for GFAAS. Measurement of a certified sample (Certified Danish Whole Blood) at a blood lead concentration of 26.2 micrograms/dL gave within- and between-run coefficients of variation which were both approximately 8% by LCS and 2% by GFAAS. Comparison of the tested method (LCS) versus GFAAS from analysis of 76 samples of blood lead collected from workers in different industrial sectors showed imperfect overall correlation (r = 0.95). The LCS is quite suitable for screening purposes, but requires the use of non-frozen blood collected less than 24 h before. Conservative threshold values should be applied when using the LCS for initial screening in the field.