The application of molecular and cellular biology, neurobiology, and pharmacology to the study of injury has shed new light on the pathophysiology and treatment of injury. As an example, study of the role of calcium as a mediator of cell death following brain injury has provided hope that pharmacologic interventions can inhibit this process (Saatman et al., 1996). The exchange of information from other fields has further enhanced the body of knowledge in injury pathophysiology. For example, injury researchers have drawn on cancer biology to study apoptosis, the process of programmed cell death, in relation to injury (Rink et al., 1995; Liu et al., 1997). The application of knowledge regarding apoptosis to the study of populations of cells that die after brain or spinal cord injury has resulted in more sophisticated thinking about a cascade of biochemical events triggered by injury. Knowledge of a greater number of biochemical steps in the process of cell death results in more possibilities for intervention. Promoting the exchange of information and techniques from other areas of research can increase the resources and talent available to solve the complex problems of injury etiology and prevention.

Additionally, there are new and promising developments in the study of the relationship between injury and disease. For example, clinical data have suggested that an episode of trauma to the musculoskeletal system can lead to osteoarthritis many years after the event. Recent biomechanics research has shown that nondebilitating trauma to the knee can cause long-term osteoarthritis in the knee joint (Haut et al., 1995; Newberry et al., 1997). Similarly, clinical data have shown that neuropathological changes in brain-injured patients exhibit striking parallels to brains of Alzheimer's patients (Graham et al., 1995, 1996). The relationship between neurodegenerative diseases and traumatic brain injury is even more convincing in experimental models of brain injury (Roberts et al., 1994) and suggests both a new direction for brain injury prevention and treatment research and the need to extend studies on injury outcomes to include debilitating neurodegenerative disorders.

The importance of behavioral research to injury prevention was highlighted more than three decades ago by William Haddon in his early publications on preventing motor vehicle injuries (Haddon et al., 1964). The behavioral sciences contribute to injury research by developing knowledge about psychosocial de-