The Effects of Steroid Hormones on Local and General Reticuloendothelial Activity: Relation of Steroid Structure to Function. In: Luzio NRD, Paoletti R, editors. The Reticuloendothelial System and Atherosclerosis. Boston: Springer US; 1967. pp. 221-42. [DOI: 10.1007/978-1-4684-7796-2_21]

Hormetic Dose-Response Relationships in Immunology: Occurrence, Quantitative Features of the Dose Response, Mechanistic Foundations, and Clinical Implications

This article provides an assessment of the occurrence of immune-system-related hormetic-like biphasic dose-response relationships. Such dose-response relationships are extensive, with over 90 different immune response-related endpoints reported, induced by over 70 endogenous agonists, over 100 drugs, and over 40 environmental contaminants. Such hormetic responses were reported in over 30 animal models, over a dozen mammalian and human cell lines. These findings demonstrate that immune-system-related hormetic-like biphasic dose-response relationships are common and highly generalizable according to model, endpoint, and chemical class. The quantitative features of the dose response are generally consistent with previously published examples of hormetic dose responses for other biological endpoints. These findings were generally recognized and explicitly discussed by the original authors, often with consideration given to possible mechanistic foundations as well as numerous clinical implications. Despite the recognition by individual authors of the hormetic nature of these observed responses, the overall widespread nature of immune-related hormetic responses has been only little appreciated, with a general lack of insight into the highly generalizable nature of this phenomenon as well as the complex regulatory networks affecting biological switching mechanisms that result in the hormetic responses.

Phagocytosis of necrotic muscle in muscle isografts is influenced by the strain, age, and sex of host mice

In grafts of skeletal muscle the implanted muscle becomes necrotic, is phagocytosed and replaced by new muscle cells. This study investigates the hypothesis that removal (phagocytosis) of necrotic implanted muscle is impaired in grafts made into old Swiss mice. Isografts (154) of minced muscle were made between young (20 day) and old (140 day) mice of the strain Swiss, AKR, BALBc, C3H and C57BL. Grafts were examined histologically after 7 days. A relationship between impaired phagocytosis and increasing host age was confirmed for male Swiss mice but was not seen with female Swiss mice or the other four strains. The proposal that ageing of bone marrow was responsible for diminished phagocytosis in old Swiss mice was investigated by replacing the marrow of 33 lethally irradiated male Swiss mice with marrow cells from mice of different ages (20 and 140 day), before isografting minced muscle. The results clearly show that macrophage stem cell function is unimpaired with age. Testosterone levels might account for the impaired phagocytosis seen in many sexually mature male Swiss mice. Support for this proposal came from experiments in which 15 mice were castrated before implanting muscle isografts. This study shows that genetic factors rather than the age of mice influenced phagocytosis and muscle formation in grafts.

Comparison of the effects of alclofenac, flurbiprofen, and prednisolone on acute inflammatory response in the rat

The fluid and cellular phases of the inflammatory response were measured using a technique employing subcutaneous implantation of polyurethane foam cubes impregnated with heat-killed Mycobacterium tuberculosis. Fluribiprofen and prednisolone were equipotent and were capable of almost completely suppressing fluid and cellular responses, while alclofenac was less potent at nontoxic dose levels. Study of the patterns of cellular exudation by image analysing computer showed that alcofenac appears unique in that it produces a well-defined cell-free zone between the edge of the implanted cubes and a band of neutrophil polymorphs within the cubes.