Biological stress response terminology: Integrating the concepts of adaptive response and preconditioning stress within a hormetic dose-response framework.

Many biological subdisciplines that regularly assess dose-response relationships have identified an evolutionarily conserved process in which a low dose of a stressful stimulus activates an adaptive response that increases the resistance of the cell or organism to a moderate to severe level of stress. Due to a lack of frequent interaction among scientists in these many areas, there has emerged a broad range of terms that describe such dose-response relationships. This situation has become problematic because the different terms describe a family of similar biological responses (e.g., adaptive response, preconditioning, hormesis), adversely affecting interdisciplinary communication, and possibly even obscuring generalizable features and central biological concepts. With support from scientists in a broad range of disciplines, this article offers a set of recommendations we believe can achieve greater conceptual harmony in dose-response terminology, as well as better understanding and communication across the broad spectrum of biological disciplines.

Hormesis: how it could affect the risk assessment process.

If the hormetic dose-response were accepted as the default dose-response model for risk assessment, it could have important implications for environmental exposure standards for noncarcinogens and especially for carcinogens. Most notably it would lead to the recognition that carcinogens act via a threshold process rejecting the concept of linearity at low doses. The hormetic concept also provides agencies with a broader range of toxicologically based exposure options, which permit a consideration for avoiding harm, as well as possibly enhancing benefits for both normal and high-risk segments of the population. By dismissing hormesis, regulatory agencies such as EPA deny the public the opportunity for optimal health and avoidance of disease.

Silicone gel breast implant rupture rates: research issues.

Documenting the rate of rupture of silicone breast implants appears to be deceptively easy. Largely because of the phenomenon of "silent rupture," it isn't. The authors explore the various technical biases (selection, misclassification, and confounding) and methodological problems that have plagued much of the research conducted to date. By means of a series of illustrations, they argue that explantation has limited utility. Noninvasive techniques have to be used to gather the proper type of data on the timing and frequency of these events. Only with the proper incidence data will researchers be able to identify better the different mechanisms underlying implant rupture and the relative importance of each. The authors recommend that better and standardized definitions of implant rupture be developed, that greater recognition be given to the technical biases and a greater effort be made to eliminate them from investigations of implant rupture, and that more research be conducted by multidisciplinary teams. Because of the growing awareness of the complexity of this issue, the authors also recommend that properly constituted advisory teams be used to provide comprehensive oversight of future research projects from beginning to end.