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Palladium (Pd) is a heavy metal belonging to the platinum group elements. It has been shown that Pd and its compounds can cause sensitization, asthma and dermatologic disorders. In this study, Wistar rats were exposed for 3 months to 0, 1, 10, 100, and 250 ng/ml of Pd (as potassium hexachloro-palladate) in drinking water. At the end of exposure, possible changes in two type-1 cytokines [interleukin (IL)-2, interferon (INF)-γ] and one type- 2 cytokine (IL-4) in the serum were measured. After the sub-chronic exposure, analysis of variance of IL-2 and INF-γ response shows that the difference between mean values in the groups of animals exposed reaches statistical significance for IL-2 (P = 0.001), showing a J-shaped dose-response relationship. At the higher dose of 250 ng/ml Pd, it was observed a significant increase in IL-2 production when compared with the controls. Furthermore at 1 and 10 ng/ml of Pd we observed an increase of INF-γ production that was significant at 100 ng/ml of Pd, while at the higher dose of 250 ng/ml of Pd the response was indistinguishable from the control. At the doses investigated, Pd has been shown not to determine a modification of IL-4 response (P = 0.10). These preliminary findings indicate the need to carry out further investigalions regarding the effect of other Pd compounds and the measurement of other types of cytokines both in the animal model used in our study and other models. [ABSTRACT FROM AUTHOR]

In 2006, Henschler disputed the claim of Calabrese and Baldwin that Hugo Schulz should be considered the originator of the hormesis concept. Henschler cited an 1854 paper by Rudolf Virchow on the effects of two agents on the beating of cilia, which showed a hormetic–biphasic dose response. The interpretation of Henschler became broadly accepted over the past decade based on citations in the literature. However, a recent translation of the Virchow paper from German into English reveals that the claims of Henschler are not supported by the article. [ABSTRACT FROM AUTHOR]

The article examines the hormetic dose responses. According to the author, hormetic dose response is dominant in various areas of the pharmaceuticals including anxiolytic drugs, antiseizure drugs, and memory enhancing agents. It is also a dominant dose response within the biomedical sciences including toxicology. Moreover, it is noted that it occurred in approximately 40% of dose responses.

The author focuses on hormesis and explains how hormesis can be related to some ethical issues. He explains that hormesis as a biological concept about the dose response. He claims that ethical issues related to hormesis come in as experts try to propose processes of risk assessment and risk communication. Because of their relation, he emphasizes the importance of examining hormesis within ethics framework.