Trace metal grade nitric acid

RG-2 tumor bearing rats were injected IV with either 5 or 10 mg TLD1433/kg body weight (bw) equivalent Rutherrin. Rats were killed at either 4, 24, or 48 hours post-Rutherrin injection. The skull was opened, and tissue samples from RG-2 tumor, the contralateral frontal cortex and the cerebellum were harvested. The fresh tissue samples were weighed and digested with 2 mL of trace metal grade nitric acid (Sigma-Aldrich). Inductively coupled plasma mass spectrometry quantification of the ¹⁰¹Ru isotope followed established standard operating procedures and the measured ppb was converted using ppb approximate μg/L units and the dilution with 2 mL acid digest volume. The TLD1433 per sample [μg] = Ruthenium mass [μg] × 1007MW_TLD1433[g/mole]/AM_Ru[g/mole]. A minimum of n = 3 animals were used to determine the specific uptake ratio (SUR) given by the ratio of RG-2 target TLD1433 versus contralateral brain or cerebellum using average tissues concentrations. PpIX tissue concentrations were obtained by tissue solubilization and fluorescence quantifications as previously reported.^{25 (link)}

Samples for determination of total cellular Cu contents were prepared as described earlier^{15 (link)}. Briefly, R. capsulatus strains were grown by respiration in 1 L of enriched MPYE medium prepared with metal-free water (stirred at room temperature with Chelex100 at a concentration of 5 g/L for 1 hour) to an OD₆₃₀ of 0.8–0.9. Cells were harvested by centrifugation and washed three times with metal-free 20 mM Tris-HCl pH 8.0 and once with ice cold metal free water. Cell pellets were lyophilized to complete dryness. A total of 50 mg of dry cell powder per sample was digested in 1 ml trace-metal grade nitric acid (Sigma) at 65 °C. To obtain a corresponding blank, the volume of the cell powder was replaced by milli-Q grade water (ultrapure) and treated the same as the samples. The digested samples were then diluted with milli-Q grade water to a final concentration of 1 mg/ml cell powder. Total metal content was measured by ICP-MS (Nexion 350D, Perkin Elmer equipped with an Element Scientific prepFAST M5 autosampler) using quadruplicate digested samples for each strain.