Assessment of a Discogenic Pain Animal Model Induced by Applying Continuous Shear Force to Intervertebral Discs.

BACKGROUND: Chronic discogenic pain includes degeneration-driven changes under the mechanical macroenvironment of an internal disc, which leads to the progressive changes of biochemical microenvironment that induce abnormal ingrowth of the nociceptor. The propriety of the animal model reflecting the pathologic natural history has not been assessed. OBJECTIVES: This study investigated the biochemical evidence of chronic discogenic pain by employing a discogenic pain animal model induced by shear force. STUDY DESIGN: Animal study utilizing rats in vivo model of a shear force device. METHODS: Fifteen rats were divided into 3 groups (n = 5/group) according to the period for which sustained dorsoventral shear force was applied (1 week or 2 weeks); the control group received the spinous attachment unit, without a spring. Pain data were collected using von Frey hairs on the hind paws. Growth factor and cytokine abundance was analyzed in the dorsal root ganglion (DRG) and plasma. RESULTS: After the shear force devices were installed, the significant variables were found to markedly increase in the DRG tissues of the 2-week group; however, they were not altered in the 1-week group. Specifically, interleukin (IL)-6, neurogrowth factor (NGF), transforming growth factor (TGF)-alpha, platelet-derived growth factor (PDGF)-beta, and vascular endothelial growth factor (VEGF) were increased. Meanwhile, the plasma levels of tumor necrosis factor-alpha, IL-1beta, IL-5, IL-6, IL-12, and NGF were increased in the 1-week group; whereas, TGF-alpha, PDGF-beta, and VEGF were increased in the 2-week group. LIMITATIONS: The limitations include the general limitations of quadrupedal animals, the poor precision and flexural deformation of shear force devices, inaccuracies regarding the evaluation of histological denaturation, and short intervention and observational periods. CONCLUSIONS: This animal model effectively generated biochemical responses to shear loading with evidence of neurological changes induced without direct macrodamage to the outer annulus fibrosus. Chemical internals were induced by mechanical externals among the contributing factors of chronic discogenic pain.

Filling potholes on the implementation highway: Evaluating the implementation of Parent-Child Interaction Therapy in Los Angeles County.

In October 2012, first 5 LA funded a unique collaboration between Los Angeles County Department of Mental Health (DMH) and UC Davis PCIT Training Center (UCD PCIT) to train county-contracted agencies to provide Parent-Child Interaction Therapy (PCIT). This $20 million dollar, 5-year grant represented the largest implementation effort of an empirically based treatment to date. The purpose of this paper was to describe the first 2 years of the implementation process of this project, beginning with project start up and pre-implementation phases, and to present agency training and client performance outcomes from our first year of training. Results presented in this evaluation suggest that it is possible to train LA County providers in PCIT, and that PCIT is an effective intervention for DMH-contracted providers in LA County. This evaluation also discusses challenges to successful implementation. Barriers to progress included unanticipated delays building county infrastructure, trainee attrition, and insufficient client referrals. We discuss the results of the current implementation with respect to theory, research, and others' training models, with the aim of evaluating and prioritizing different implementation drivers, noting the ongoing competition between knowing what to do and the need for action.