Our laboratory is accredited for lead analysis in blood according to the Swedish Board for Accreditation and Conformity Assessment (SWEDAC), and during the period, we also produced good results in the UK National External Quality Assessment Service (Birmingham, UK); our mean accuracy was 96% with coefficient of variation <5%. Other Blood haemoglobin (B-Hb) was analysed by a standard clinical method. U0126 supplier Creatinine (crea) was analysed in
urine samples by a modified kinetic Jaffé method (Roche Diagnostics, Mannheim, Germany). Both B-Hb and crea were analysed by an accredited clinical laboratory with scrupulous quality control. Detection limit for crea was 0.1 mmol/L and total imprecision 1.6%. For B-Hb measurements, the imprecision within the working range of 1–250 g/L was ≤1.0%. Toxicokinetic modelling Non-linear regression
analysis was performed with SPSS version 15.0, according to Eq. (1). The first exponential term describes the fast elimination phase, the second one, the slow elimination of Pb. $$ C_\textPb (t) \, = \, C_1 *\texte^( – R_1 *t) + C_2 *\texte^( – 0.000146*t) $$ (1) C Pb(t), lead concentration at a given time (μg/L), t, time (days), C 1, constant (concentration Tariquidar molecular weight of the fast phase at t = 0), C 2, constant (concentration of slow phase at t = 0), R 1, elimination constant of phase 1 (days−1). The follow-up Clostridium perfringens alpha toxin time was not sufficient to calculate the half-time in the slow phase. Nilsson et al. (1991) found it to be 13 years in a long-term study of Pb workers. Therefore, that value was used. The sum of C 1 and C 2 describes the modelled Pb content at the end of
exposure (t = 0). The half-time of Pb in the fast phase has been calculated according to Eq. (2). $$ T_\raise0.5ex\hbox$\scriptstyle 1$ \kern-0.1em/\kern-0.15em \lower0.25ex\hbox$\scriptstyle 2$ = \raise0.7ex\hbox$\ln 2$ \!\mathord\left/ \vphantom \ln 2 R_1 \right.\kern-\nulldelimiterspace \!\lower0.7ex\hbox$R_1 $ $$ (2)For three cases, there were sufficient data to describe the relationship between B–Hb and P–Pb after end of exposure. Inspection of the curves (Fig. 4) indicated that one component did not give a GW3965 order satisfactory fit. Regression lines were calculated on the left and right sides of the division line (x = 5 μg P–Pb/L), and statistical significance of the difference between the pairs of slopes was examined. After that the threshold between the two components was calculated as the crossing point of the two lines. Genotyping DNA was isolated from whole blood by minicolumn purification (E.Z.N.A DNA extraction kit, Omega Bio-Tek, Norcross, GA, USA) and diluted to a concentration of 5 ng/μL.