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An analytical procedure was developed to determine the concentration of 25 impurities (Li, Be, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Mo, Ag, Cd, In, Sm, Eu, Gd, Dy, W, Pb, Bi and Th) in a uranium matrix using the quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS). The dissolution of U(3)O(8) powder was made with a mixture of hydrochloric acid and nitric acid. Then, a selective separation of uranium using the UTEVA column was used before measurement by Q-ICP-MS. The procedure developed was verified using the Certified Reference Material "Morille". The analytical results agree well except for 5 elements where values are underestimated (Li, Be, In, Pb and Bi). Among the list of impurities, iron was particularly investigated because it is well known that this element possesses a polyatomic interference that increases the detection limit. A comparison between iron detection limits obtained with different methods was performed. Iron polyatomic interference was at least reduced, or at best entirely resolved in some cases, by using the cold plasma or the collision/reaction cell with several gases (He, NH(3) and CH(4)). High-resolution ICP-MS was used to compare the results obtained. A detection limit as low as 8 ng L(-1) was achieved., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Nucleolar organizer regions (NOR) have DNA loops containing genes that encode for ribosomal RNA; some proteins located near the NORs are argyrophilic and by Ploton's one step method we could quantify the NORs in sections of paraffin embedded tissues. We have evaluated the number of intranuclear dots in 46 parathyroid glands from 18 parathyroidectomies. The glands were weighed and the stromal fat was evaluated by a point-counting method. AgNORs were counted in 100 cells from each gland. The mean count was 3.03 in six adenomas (A), 2.39 in six cases of primary hyperparathyroidism (PH) and 2.63 in six cases of secondary hyperparathyroidism (SH). Statistical analysis performed by Mann-Whitney U test showed that differences between A and PH groups were significant. The difference between A and SH was also significant. The residual parathyroid tissue surrounding the adenoma had a significantly lower AgNOR mean count than adenomatous cells. The AgNOR mean number can be useful in assessing normal or suppressed parathyroid tissue.