A polymorphism in the delta-aminolevulinic acid dehydratase gene modifies plasma/whole blood lead ratio

Delta aminolevulinic acid dehydratase (ALAD) plays an important role in lead poisoning. This study was carried out to examine the effects of ALAD gene polymorphism (G177C) on %Pb-P(plasma lead)/Pb-B(whole blood) ratio in 142 subjects environmentally exposed to lead. Genotypes for the ALAD G177C polymorphism were determined by PCR and restriction fragment length digestion. Pb-P and Pb-B were determined by inductively coupled plasma mass spectrometry and by graphite furnace atomic absorption spectrometry, respectively. The allele frequencies for ALAD1 and ALAD2 alleles were 0.897 and 0.103, respectively. We combined both ALAD 1-2 and ALAD 2-2 genotypes together (ALAD 1-2/2-2 group) and compared with the ALAD 1-1 genotype group. While no significant differences were found in Pb-B, subjects from the ALAD 1-2/2-2 genotype group presented significantly higher Pb-P concentrations and %Pb-P/Pb-B ratios (0.89±0.07 μg/l, and 1.45±0.10%, respectively) when compared with subjects from the ALAD 1-1 genotype group (0.44±0.05 μg/l, and 0.48±0.02, respectively; both P<0.0001). The higher %Pb-P/Pb-B ratios in carriers of the ALAD-2 allele compared with noncarriers indicate that ALAD 1-2/2-2 subjects are probably at increased health risks associated with lead exposure.     

Matrix metalloproteinase-9 activity in plasma correlates with plasma and whole blood lead concentrations

Matrix metalloproteinases (MMPs) are enzymes involved in the degradation of the extracellular matrix. MMP-2 and MMP-9 have been implicated in a variety of pathological conditions including cardiovascular and neoplastic diseases, and recent studies have shown that circulating concentrations of MMP-9 may be a marker helping in the diagnosis and prognosis of cardiovascular and neoplastic diseases. We investigated whether there is an association between plasma MMP-2 and MMP-9 activities and the concentrations of lead in whole blood (blood Pb) or plasma (plasma Pb) from 40 lead-exposed persons (22 men and 18 women). Plasma Pb was determined by inductively coupled plasma mass spectrometry (ICP-MS) and blood Pb by graphite furnace atomic absorption spectrometry (GF-AAS). Plasma MMP-2 and MMP-9 activities were measured by gelatin zymography. We found a significant correlation between pro-MMP-9 activity in plasma and blood Pb (r=0.454; P=0.003), and between pro-MMP-9 activity in plasma and plasma Pb (r=0.312; P=0.049). No significant correlations were found between blood Pb or plasma Pb and plasma MMP-2. The association between pro-MMP-9 activity in plasma and both blood Pb and plasma Pb concentrations suggests a mechanism through which low lead exposure may increase the susceptibility to cardiovascular and neoplastic diseases. A causal relationship, however, remains to be proved.     

Assessment of cyclosporin A in whole blood and plasma in five patients with different hematocrits

Measurement of whole blood and plasma levels of cyclosporin A (CsA) by radioimmunoassay in kidney transplant recipients receiving the drug showed that CsA concentrations in plasma increased nonlinearly when whole blood levels of the drug exceeded 1,000 ng/ml. At low plasma levels (less than 200 ng/ml), most of the CsA in the blood was in the nonplasma component, indicating that cellular elements have high affinity for CsA. Comparison of nonplasma CsA concentrations in two patients with hematocrit values of 32.5 and 35% showed that in the patient with a hematocrit of 35% the cellular associated drug was twice as great as that in the other patient, indicating that there may be significant differences in the cellular affinity of CsA in patients with similar hematocrits. Linear regression analysis of the cellular associated CsA versus plasma levels of the drug in a double-reciprocal plot showed a drug saturation capacity of 6,060 ng/ml in the nonplasma component of blood in the patient with a hematocrit of 35%. Similar analyses in the other patients indicated saturation capacities ranging from 4,750 to 10,400 ng/ml.     

Revisiting mobilisation of skeletal lead during pregnancy based on monthly sampling and cord/maternal blood lead relationships confirm placental transfer of lead

Lead (Pb) can be released from the maternal skeleton during pregnancy and lactation and transferred to the infant. Most support for this hypothesis comes from blood Pb (PbB) studies involving limited sampling during pregnancy, the maximum usually being five samplings, including at delivery. We provide longitudinal data for PbB concentrations and Pb isotopic ratios for three cohorts of pregnant females (n = 31), two of which are based on monthly sampling and the other on quarterly sampling. We also provide data for samples collected post-partum. The data are compared with changes observed in a matched, by country and age, non-pregnant control cohort (n = 5). The monthly data illustrate the variability between subjects, which is also apparent when the data are compared on a trimester basis. Mixed model analyses showed that, in the third trimester, the mean PbB level was significantly lower for women (n = 10) who took a calcium (Ca) supplement (PbB 1.6 µg/dL) than those whose Ca intake was low (low-Ca cohort; n = 15; PbB 2.5 µg/dL) because low Ca means more mobilisation is required for homoeostasis so that more Pb was mobilised from the skeleton. For women who took the supplement, post-partum PbB levels were significantly higher than those in the other periods (2.7 vs 1.4–1.6 µg/dL). For women in the low-Ca cohort, PbB levels were higher at post-partum than in pre-pregnancy and in the first and second trimesters (3.1 vs 1.8 µg/dL), while the levels in the third trimester were higher than those in the first and second trimesters. Importantly, the increase in PbB during gestation was delayed until the third trimester in the Ca-supplemented cohort compared with the low-Ca cohort. Regression analysis showed that the changes over trimester were very similar for PbB and the ²⁰⁶Pb/²⁰⁴Pb ratio providing convincing evidence for extra mobilisation of Pb from the maternal skeleton during pregnancy and lactation. Isotopic ratios in the cord blood samples were similar to those in the maternal blood samples taken prior to parturition with an R ² 0.94 for the migrant subjects and R ² 0.74 for Australian subjects for ²⁰⁶Pb/²⁰⁴Pb ratios, supporting the concept of placental transfer of mobilised skeletal stores of Pb.     

Increased urinary cobalt and whole blood concentrations of cadmium and lead in women with uterine leiomyomata: Findings from the ENDO Study

Multiple trace elements have estrogen receptor activity, but the association of these elements with uterine leiomyoma has not been defined. A cohort of 473 women aged 18–44 undergoing surgery for benign gynecologic indications provided whole blood and urine specimens for trace element analysis, which was performed by inductively coupled plasma mass spectrometry. Twenty elements were analyzed in blood and 3 in urine. The surgeon documented whether fibroids were present. Geometric mean concentrations were compared between women with and without fibroids, and logistic regression models were generated to assess the impact of the concentration of each trace element on the odds of fibroids. In multivariate regressions, odds of a fibroid diagnosis were higher with increased whole blood cadmium (AOR 1.44, 95% CI 1.02, 2.04) and lead (AOR 1.31 95% CI 1.02, 1.69), and urine cobalt (AOR 1.31, 95% CI 1.02, 1.70). Urinary cadmium and lead were not related to fibroid diagnosis. Increased exposure to trace elements may contribute to fibroid growth, and fibroids may serve as a reservoir for these elements. Differences between urinary and whole blood findings merit further investigation, as urinary cadmium has been considered a superior marker of exposure.     

Effects of perinatal treatment with lead and disulfiram on ALAD activity in blood, liver and kidney and urinary ALA excretion in rats

Disulfiram, which is metabolized to diethyldithiocarbamate, is known to greatly influence the tissue distribution of lead (Pb) and potentiate the toxic effect of lead in the central nervous system. Effects on delta-aminolevulinic acid dehydratase (ALAD) activity and urinary delta-aminolevulinic acid (ALA) excretion were studied in rats pre- and postnatally exposed to lead and disulfiram, singly or in combination. Pregnant rats were treated with lead (0.25% Pb in the drinking water), with disulfiram (0.1 mmol/kg orally twice a week) or with both lead and disulfiram from day 1 of pregnancy until weaning. After parturition the disulfiram was given subcutaneously directly to the offspring. ALAD activity in blood was inhibited to a similar extent in the group treated with lead alone and in the group treated with lead and disulfiram (7 and 10% of control activity, respectively). Liver and kidney ALAD activities were not affected by the combined treatment with lead and disulfiram. However, urinary excretion of ALA was increased twice as much in the group treated with lead and disulfiram as in the group treated with only lead. The haematocrits were also significantly more depressed after combined exposure to lead and disulfiram. Two weeks after cessation of exposure ALAD activity in blood was inhibited to 47% of control activity in both the lead- and the lead plus disulfiram-treated groups. At this time there was no effect due to treatment on urinary ALA excretion of haematocrit. The results indicate that disulfiram probably influences the effects of lead on ALAD activity at the site of haem synthesis in the bone marrow.2+t is     

随机尿白蛋白/肌酐比值在妊娠期高血压疾病中的诊断价值

摘要： 目的 探讨随机尿白蛋白/肌酐比值（ACR）与 24 h 尿蛋白等指标的相关性, 及其在妊娠期高血压疾病（HDCP）中的诊断价值。 方法 测定并比较 584 例 HDCP 患者（其中妊娠期高血压组 169 例, 轻度子痫前期组 205例、重度子痫前期组 173 例及慢性高血压组 37 例）和 2 038 例正常单胎孕妇（正常组）ACR、24 h 尿蛋白及其他生化指标的差异, 对 ACR 与 24 h 尿蛋白等进行相关分析, 受试者工作曲线（ROC）分析 ACR 诊断 HDCP 的敏感度和特异 度, ROC 曲线下面积得出 ACR 诊断 HDCP 的最佳诊断值。 结果 （1）重度子痫前期组比其他亚组 ACR、24 h 尿蛋白、尿素氮、肌酐、尿酸、总胆固醇、低密度脂蛋白胆固醇显著增高, 血小板计数、白蛋白、总蛋白显著降低（P < 0.05）。（2）ACR 与 24 h 尿蛋白、尿素氮、肌酐、尿酸、D 二聚体、总胆固醇、低密度脂蛋白胆固醇呈正相关（P < 0.05）; 与白蛋白、总蛋白、血小板计数呈负相关（P < 0.05）。（3）ACR 诊断妊娠期高血压、轻度子痫前期、重度子痫前期及极重度子痫前期的最佳值分别为 1.44 、10.48、39.84 及 94.91 g/mol。 结论 ACR 在 HDCP 中与 24 h 尿蛋白高度相关,可用于诊断 HDCP 及判断病情严重程度。     

Comparison of plasma, serum, and whole blood ethanol concentrations

The differences in ethanol concentrations, as measured by direct injection gas chromatography, among plasma, serum, and whole blood from living human subjects are examined. The samples containing serum and the corresponding ones containing whole blood arrived at the laboratory as part of the same submission. The ratio of the concentration of ethanol in serum to that in plasma is 1.00 +/- 0.01:1 with a range of 0.98:1 to 1.04:1. The serum/whole blood ratio and plasma/whole blood ratio are both 1.12 +/- 0.02:1. The former has a range of 1.09:1 to 1.18:1 and the latter ranges from 1.09:1 to 1.17:1.     

Relationships of maternal blood lead and disorders of pregnancy to neonatal birthweight

Transient complications of pregnancy (anemia, toxemia, proteinuria, arterial hypertension and hyperemesis) were studied in pregnant women from the general population reporting to local hospitals. Comparison of blood lead levels (PbB) was made between women with normal pregnancies and those with complications. Significantly higher PbB were found in women with pregnancy complications as compared to those with normal pregnancies. Increments in the PbB levels were accompanied by statistically significant decrements in neonate birthweights. Complications of pregnancy may be induced by higher PbB and may also compound the adverse effects of decrements of neonate birthweights     

Evaluation of the use of salivary lead levels as a surrogate of blood lead or plasma lead levels in lead exposed subjects

We conducted a study to evaluate the use of parotid salivary lead (Pb-saliva) levels as a surrogate of the blood lead (Pb-B) or plasma lead levels (Pb-P) to diagnose lead exposure. The relationship between these biomarkers was assessed in a lead exposed population. Pb-saliva and Pb-P were determined by inductively coupled plasma mass spectrometry, while in whole blood lead was determined by graphite furnace atomic absorption spectrometry. We studied 88 adults (31 men and 57 women) from 18 to 60 years old. Pb-saliva levels varied from 0.05 to 4.4 μg/l, with a mean of 0.85 μg/l. Blood lead levels varied from 32.0 to 428.0 μg/l in men (mean 112.3 μg/l) and from 25.0 to 263.0 μg/l (mean 63.5 μg/l) in women. Corresponding Pb-Ps were 0.02–2.50 μg/l (mean 0.77 μg/l) and 0.03–1.6 μg/l (mean 0.42 μg/l) in men and women, respectively. A weak correlation was found between Log Pb-saliva and Log Pb-B (r=0.277, P<0.008), and between Log Pb-saliva and Log Pb-P (r=0.280, P=0.006). The Pb-saliva/Pb-P ratio ranged from 0.20 to 18.0. Age or gender does not affect Pb-saliva levels or Pb-saliva/Pb-P ratio. Taken together, these results suggest that salivary lead may not be used as a biomarker to diagnose lead exposure nor as a surrogate of plasma lead levels at least for low to moderately lead exposed population.     

GC-MS determination of flunitrazepam and its major metabolite in whole blood and plasma.

A gas chromatography-mass spectrometry method was developed for the analysis of flunitrazepam (FN) and its major metabolite, 7-amino-flunitrazepam (7-amino-FN), in both plasma and whole blood. The method was based on acid hydrolysis of the samples after dilution with HPLC water followed by extraction and derivatization (heptafluorobutyrate) of the resulting benzophenones. Analysis of plasma and whole blood samples from subjects administered 2-mg doses of FN showed that FN was only detected in whole blood (LOD 5 ng/mL) and not in plasma. However, 7-amino-FN was detected in both plasma and whole blood, although the levels were much higher in plasma. 7-Amino-FN was detected for the entire period of specimen collection (12 h), but FN was only detected in whole blood for 4 h after ingestion with peak levels after 1 h.     

Quantitation and ultraviolet spectrum identification of buflomedil in whole blood and plasma by HPLC

Buflomedil, a vasodilating agent, was determined in whole blood or plasma by HPLC with papaverine as internal standard after absorption of the alkaline sample on an Extrelut column and elution with diethylether-methylene chloride (70:30, v/v). The eluate was evaporated and the residue was dissolved in 100 microL of the mobile phase; 20 microL of this solution were injected into a mu Bondapak C18 column (10 microns) using acetonitrile-0.125M potassium dihydrogen phosphate (40:60, v/v) as mobile phase and UV detection at 280 nm, followed by UV spectrum identification (between 200 and 350 nm) with a photodiode array detector. The method is rapid (giving response within 20 min), reproducible, selective, and sensitive. It can be applied for pharmacokinetic studies and for both clinical pharmacology and forensic toxicology.     

Population pharmacokinetics of tacrolimus in whole blood and plasma in asian liver transplant patients

OBJECTIVES: The objectives of this study were to develop population pharmacokinetic models of tacrolimus in an Asian population with whole blood and plasma drug concentration data, to compare the variability of the pharmacokinetic parameters in these two matrices and to search for the main patient characteristics that explain the variability in pharmacokinetic parameters. STUDY DESIGN: Prospective pharmacokinetic assessment followed by model fitting. PATIENTS: Whole blood samples from 31 liver transplant patients in a local hospital receiving oral tacrolimus as part of their immunosuppressive therapy were assessed. Plasma samples from 29 of the 31 patients were also evaluated. Concentrations of tacrolimus in whole blood and plasma were determined by an electrospray high-performance liquid chromatography with tandem mass spectrometry. Two hundred and thirteen whole blood and 157 plasma tacrolimus concentrations were used for building two nonlinear mixed-effects population models to describe the disposition of tacrolimus in whole blood and plasma, respectively. Covariates that were investigated included demographic characteristics, biological markers of liver and renal functions, corticosteroid dose and haematological parameter. RESULTS: A one-compartment model was used to describe the whole blood and plasma concentration-time data of tacrolimus after oral administration. For the whole blood population model, the population estimates of the first-order absorption rate constant (k(a)), apparent clearance based on whole blood concentration after oral administration (CL(B)/F) and apparent volume of distribution based on whole blood concentrations after oral administration (V(d,B)/F) were 2.08h(-1), 14.1 L/h and 217L, respectively. The coefficient of variations (CVs) of interpatient variabilities in CL(B)/F and V(d,B)/F were 65.7% and 63.8%, respectively. Bodyweight, liver and renal function influenced CL(B)/F, while height and haematocrit influenced V(d,B)/F. The residual (unexplained) variability was 34.8%. For the plasma population model, the population estimates of the k(a), apparent clearance based on plasma concentrations after oral administration (CL(P)/F) and apparent volume of distribution based on plasma concentrations after oral administration (V(d,P)/F) were 5.21h(-1), 537 L/h and 563L, respectively. The CVs of interpatient variabilities in CL(P)/F and V(d,P)/F were 96.0% and 105.4%, respectively. Bodyweight was found to influence CL(P)/F, while the erythrocyte-to-plasma concentration ratio influenced V(d,P)/F. The residual (unexplained) variability was 49.8% at the mean plasma concentration of 1.1 ng/mL. CONCLUSIONS: Whole blood and plasma population pharmacokinetic models of tacrolimus in Asian adult and paediatric liver transplant patients were developed using prospective data in a clinical setting. This has identified and quantified sources of interindividual variability in CL(B)/F, V(d,B)/F, CL(P)/F and V(d,P)/F of tacrolimus in Asian liver transplant patients. Information derived from the whole blood population model may subsequently be used by clinicians for dosage individualisation through Bayesian forecasting.     

Stability of phosphatidylethanol 16:0/18:1 in authentic and spiked whole blood

Phosphatidylethanol 16:0/18:1 (PEth) is the most abundant homologue of the phosphatidylethanol group of phospholipids. Formed only in the presence of ethanol, PEth is used as a biomarker in whole blood to provide information about the consumption of alcohol. As information on the storage life of PEth is essential for its beneficial use as a biomarker, this study investigated the stability of PEth in spiked and authentic whole blood samples stored at 4°C. Human whole blood samples (n = 23) and spiked whole blood samples (n = 7) with a concentration range between 5 and 2000 ng/ml were analysed at specific time intervals, up to 90 days. Differences were evident between the stability of authentic and spiked samples. PEth was stable at 4°C for 60 days (concentrations within 15% of initial concentration) in authentic samples, whereas spiked samples were stable for up to 30 days. This study emphasizes the importance of including authentic samples in stability experiments.     

RP-HPLC法测定全血、血浆和红细胞中氯氮平及2种主要代谢物

目的建立一种测定全血、血浆和红细胞中氯氮平(CZP)、N-去甲基氯氮平(N-CZP)和氯氮平N-氧化物(CZP-NO)浓度的RP-HPLC法.方法标本用乙酸乙酯提取后再经0.1mol·L-1盐酸反提取,以利培酮为内标,流动相为甲醇-乙腈-水(16.0∶36.5∶47.5),色谱柱为Inertsil-ODS-3柱,柱温为40℃,检测波长为254nm,流速为0.9mL*min-1.结果全血、血浆和红细胞中CZP和N-CZP的最低检测浓度均为7μg*L-1;血浆中CZP-NO的最低检测浓度为13μg*L-1,全血和红细胞中为14μg*L-1.全血、血浆和红细胞中CZP和N-CZP的绝对回收率均为85%～95%,血浆中CZP-NO的绝对回收率>82%,全血和红细胞中CZP-NO的绝对回收率约为70%.日内和日间RSD均小于7%.结论本法操作简便,灵敏度高,重复性好,适合于临床检测.