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This paper provides practical illustrations in the use of osteoinductive devices (biomaterial carriers coupled with osteoinductive morphogens) for bone tissue engineering. We discuss the considerations relative to the implantation of these devices that may induce tissues that are located outside the boundaries of the osteoinductive device as well as outside boundaries of the normal skeletal envelope. Five reports of osteoinductive devices generating such tissues are reviewed. Histologic and radiographic data from a sixth example are presented and compared with histologic and radiographic findings typical of two varieties of myositis ossificans. A theory is advanced that osteoinductive implants may induce ectopic tissues that resemble fibro-osseous pathologies. Finally characteristics of tissue-engineered bone graft substitutes that may contribute to development of these pathologies and device characteristics that may obviate these ectopic tissues are considered.

Although scientific inquiry using the Transtheoretical Model of Behavior (TTM) supports various behavior changes in multiple samples, no research was found that examined this model with women already infected with HIV. This article provides a brief overview of the related literature and describes a pilot study that evaluated TTM concepts in women at risk for, or infected with, HIV. The pilot study examined preliminary psychometrics of the research measures in women at risk for (n = 9), or infected with, HIV (n = 10), and examined predicted differences in situational confidence and stress management practices by HIV serostatus (positive vs. negative) and stage of change (precontemplation and contemplation vs. preparation, action, and maintenance) implied by the TTM. This pilot study supports use of the TTM to examine readiness to use stress management behavior in women regardless of their HIV serostatus. Further TTM stress management inquiry is encouraged to extend the knowledge base needed in caring for this vulnerable population.

This article presents a strategy for design, engineering, and fabrication of a bioresorbable, manufactured bone graft substitute (BGS) device. The approach is based on established precepts of osteogenesis, molecular biology of hyaluronic acid and osteoinductive proteins, and theoretical preformance criteria for such a device collated from the literature of 1991 to 1996. Application of this design and engineering strategy results in a composite device consisting of a D,D-L,L-polylactic acid macrostructure optimized to the architecture of cancellous bone, a microstructure composed of a filamentous velour of hyaluronan and a recombinant human bone morphogenetic protein 2 (rhBMP-2). The performance of this construct was tested in vivo in the dog, intertransverse process, spinal fusion model and in a critical sized defect of the rabbit radius. Data from these studies are used to illustrate principle points of the design and engineering concept.

The empirical and theoretical work of both operant and cognitive researchers has increasingly appealed to evolutionary concepts. In particular, both traditional operant studies of extinction-induced behavior and cognitive investigations of creativity and problem solving converge on the fundamental evolutionary principles of variation and selection. These contemporary developments and their implications for the alleged preparadigmatic status of psychology are discussed.

We wanted to know if incubation time and temperature for many radioimmunoassay methods could be standardized, to decrease assay time and so improve efficiency. Percentage binding was determined for triiodothyronine, thyroxine, digoxin, digitoxin, testosterone, aldosterone, estradiol, and diphenylhydantoin when the reaction mixtures were incubated at 6-8, 22, or 37 degrees C for various periods of time. In all methods tested, binding of antigen to antibody was greatest when the reaction mixtures were incubated at 6-8 degrees C, less at 22 degrees C, and least at 36 degrees C. Maximum binding occurred within 30-60 min at each temperature for all methods tested. Hence, it is possible to standardize the incubation time and temperature for these eight radioimmunoassay methods to 60 min at 6-8 degrees C.