Nontarget effects of ivermectin residues on earthworms and springtails dwelling beneath dung of treated cattle in four countries

The authorization of veterinary medicinal products requires that they be assessed for nontarget effects in the environment. Numerous field studies have assessed these effects on dung organisms. However, few studies have examined effects on soil-dwelling organisms, which might be exposed to veterinary medicinal product residues released during dung degradation. The authors compared the abundance of earthworms and springtails in soil beneath dung from untreated cattle and from cattle treated 0 d, 3 d, 7 d, 14 d, and 28 d previously with ivermectin. Study sites were located in different ecoregions in Switzerland (Continental), The Netherlands (Atlantic), France (Mediterranean), and Canada (Northern Mixed Grassland). Samples were collected using standard methods from 1 mo to 12 mo after pat deposition. Ivermectin concentrations in soil beneath dung pats ranged from 0.02 mg/kg dry weight (3 mo) to typically <0.006 mg/kg dry weight (5-7 mo). Earthworms were abundant and species-rich at the Swiss and Dutch sites, less common with fewer species at the French site, and essentially absent at the Canadian site. Diverse but highly variable communities of springtails were present at all sites. Overall, results showed little effect of residues on either earthworms or springtails. The authors recommend that inclusion of soil organisms in field studies to assess the nontarget effects of veterinary medicinal products be required only if earthworms or springtails exhibit sensitivity to the product in laboratory tests. Environ Toxicol Chem 2016;35:1959-1969. © 2015 SETAC.

Single-cell analysis of T-cell receptor-gamma rearrangements in large-cell anaplastic lymphoma

Large-cell anaplastic lymphomas (LCAL) are characterized by their distinctive morphology together with expression of the CD30 antigen. In addition, a chromosomal translocation, t(2;5) (p23; q35), can be detected in most cases. A significant proportion of LCALs carry rearrangements of the T-cell receptor-gamma (TCR-gamma) locus and display a T-cell phenotype. In about a third of the cases, another type of non-Hodgkin-lymphoma precedes LCAL. Early transformations of non-Hodgkin's lymphoma into LCAL might escape clinical detection in a significant number of cases. The existence of clonally related lymphoid cells within the lymph node infiltrates must be claimed in these cases. Recently, a small-cell-predominant variant of LCAL was described in which only few large tumor cells expressing the CD30 antigen are found together with numerous small lymphocytes, which are frequently CD30-. This observation in particular prompted us to investigate the clonal relationship of the tumor cell compartment and admixed small lymphocytes in one case of common LCAL with T-cell genotype. For this purpose, we chose to amplify rearranged TCR-gamma sequences from single cells isolated from immunostained frozen sections by using a micromanipulator. A total of 119 cells were investigated. Amplification products were obtained in 17 of 79 CD3+ cells, 12 of 30 CD30+ cells, and three of 10 CD20+ cells. The nucleotide sequences were determined in 28 cells by nonradioactive sequencing. In 11 CD30+ cells, the predominant rearrangement of TCR-gamma was identified. No clonal diversity was observed. The small CD3+ lymphocytes were unrelated to the anaplastic CD30+ tumor cells. This report describes a method to analyze rearrangements of the TCR-gamma in single cells isolated from immunostained frozen sections. Application of this technique revealed an absence of clonal diversity in a case of LCAL and documented the polyclonal nature of admixed small CD3+ lymphocytes.