Cutaneous leucocytoclastic vasculitis caused by cyclosporin A (Sandimmun)

Recommendations for the Development of Socioeconomically-Situated and Clinically-Relevant Neuroimaging Models of Pain

Pain is a complex, multidimensional experience that emerges from interactions among sensory, affective, and cognitive processes in the brain. Neuroimaging allows us to identify these component processes and model how they combine to instantiate the pain experience. However, the clinical impact of pain neuroimaging models has been limited by inadequate population sampling - young healthy college students are not representative of chronic pain patients. The biopsychosocial approach to pain management situates a person's pain within the diverse socioeconomic environments they live in. To increase the clinical relevance of pain neuroimaging models, a three-fold biopsychosocial approach to neuroimaging biomarker development is recommended. The first level calls for the development of diagnostic biomarkers via the standard population-based (nomothetic) approach with an emphasis on diverse sampling. The second level calls for the development of treatment-relevant models via a constrained person-based (idiographic) approach tailored to unique individuals. The third level calls for the development of prevention-relevant models via a novel society-based (social epidemiologic) approach that combines survey and neuroimaging data to predict chronic pain risk based on one's socioeconomic conditions. The recommendations in this article address how we can leverage pain's complexity in service of the patient and society by modeling not just individuals and populations, but also the socioeconomic structures that shape any individual's expectations of threat, safety, and resource availability.

Effect of long-term cyclosporine administration on muscle flap hemodynamics

Long-term use of cyclosporine A (CsA) is associated with deleterious effects such as nephrotoxicity and hypertension as a result of its toxicity on microvasculature. These effects raise the possibility that long-term CsA use harms the microvasculature of the skeletal muscle tissue. An experimental study was conducted to investigate the effect of chronic systemic cyclosporine administration on the microvasculature of the cremaster flap model in the rat. Thirty male Sprague-Dawley rats were divided into five groups of 6 animals each. The control group received no treatment. The four CsA treatment groups received a daily subcutaneous injection of 2 mg per kilogram, 4 mg per kilogram, 8 mg per kilogram, and 16 mg per kilogram of cyclosporine for 6 weeks before surgery. The effect of long-term CsA administration on cremaster flap microcirculation was evaluated in vivo using an intravital microscopy system. Hemodynamic parameters of the cremaster muscle flap such as vessel diameter, red blood cell velocity, capillary density, leukocyte-endothelial interaction, and microvascular permeability were measured. There was no significant (p > 0.05) difference in vessel diameter in all groups. There was a significant increase in the number of adherent leukocytes in the 8-mg and 16-mg CsA group compared with the control (12 +/- 4.8 leukocytes per 100 microm and 12 +/- 4.5 leukocytes per 100 microm vs. 6 +/- 4.3 leukocytes per 100 microm; p < 0.05). Microvascular permeability indices increased significantly at 0 and 30 minutes after fluorescent isothiocyanate-albumin injection in the 8-mg and 16-mg CsA groups compared with the control (0 minutes: 0.6 +/- 0.2% and 0.5 +/- 0.1% vs. 0.4 +/- 0.05%; 30 minutes: 0.8 +/- 0.2% and 0.7 +/- 0.1% vs. 0.5 +/- 0.04%; p < 0.05). Histologically, the cremaster muscle flaps in all cyclosporine groups showed evidence of interstitial inflammation and venous vasculitis. In the 8-mg and 16-mg CsA groups there was also focal muscle injury. The toxic effect of CsA on the microvascular tree of a muscle flap was demonstrated by the increased permeability index in vivo, and the moderate venulitis and focal muscle injury histologically. Systemic CsA administration seems to have minimal impact on the viability of the muscle flaps, which was confirmed by preserved capillary function and muscle flap perfusion. These data suggest that there is a minimal risk in undertaking a pedicled muscle flap transfer procedure using a CsA immunosuppressive protocol.