Schwann cells seeded in acellular nerve grafts improve functional recovery.

INTRODUCTION: This study evaluated whether Schwann cells (SCs) from different nerve sources transplanted into cold-preserved acellular nerve grafts (CP-ANGs) would improve functional regeneration compared with nerve isografts. METHODS: SCs isolated and expanded from motor and sensory branches of rat femoral and sciatic nerves were seeded into 14mm CP-ANGs. Growth factor expression, axonal regeneration, and functional recovery were evaluated in a 14-mm rat sciatic injury model and compared with isografts. RESULTS: At 14 days, motor or sensory-derived SCs increased expression of growth factors in CP-ANGs versus isografts. After 42 days, histomorphometric analysis found CP-ANGs with SCs and isografts had similar numbers of regenerating nerve fibers. At 84 days, muscle force generation was similar for CP-ANGs with SCs and isografts. SC source did not affect nerve fiber counts or muscle force generation. CONCLUSIONS: SCs transplanted into CP-ANGs increase functional regeneration to isograft levels; however SC nerve source did not have an effect.

Nonischemic Cardiomyopathies.

Computed tomography of the heart can characterize and differentiate various forms of nonischemic cardiomyopathy, which are covered individually in this article. With its excellent spatial and ever-improving temporal resolution, computed tomography scanning can delineate cardiac function, anatomy, and myocardial tissue characterization. Various cardiac computed tomography techniques can be tailored to the relevant clinical question, as discussed in the article. Although cardiac computed tomography scanning is not often the primary modality for myocardial evaluation, decreasing radiation doses and emerging applications make this fast and relatively economical examination a useful tool in the evaluation of the patient with cardiomyopathy.

Survey-Based Assessment of Patients' Understanding of Their Own Imaging Examinations.

PURPOSE: To perform a survey-based assessment of patients' knowledge of radiologic imaging examinations, including patients' perspectives regarding communication of such information. METHODS: Adult patients were given a voluntary survey before undergoing an outpatient imaging examination at our institution. Survey questions addressed knowledge of various aspects of the examination, as well as experiences, satisfaction, and preferences regarding communication of such knowledge. RESULTS: A total of 176 surveys were completed by patients awaiting CT (n = 45), MRI (n = 41), ultrasound (n = 46), and nuclear medicine (n = 44) examinations. A total of 97.1% and 97.8% of patients correctly identified the examination modality and the body part being imaged, respectively. A total of 45.8% correctly identified whether the examination entailed radiation; 51.1% and 71.4% of patients receiving intravenous or oral contrast, respectively, correctly indicated its administration. A total of 78.6% indicated that the ordering physician explained the examination in advance; among these, 72.1% indicated satisfaction with the explanation. A total of 21.8% and 20.5% indicated consulting the Internet, or friends and family, respectively, to learn about the examination. An overall understanding of the examination was reported by 70.8%. A total of 18.8% had unanswered questions about the examination, most commonly regarding examination logistics, contrast-agent usage, and when results would be available. A total of 52.9% were interested in discussing the examination with a radiologist in advance. Level of understanding was greatest for CT and least for nuclear medicine examinations, and lower when patients had not previously undergone the given examination. CONCLUSIONS: Patients' knowledge of their imaging examinations is frequently incomplete. The findings may motivate initiatives to improve patients' understanding of their imaging examinations, enhancing patient empowerment and contributing to patient-centered care.

A transgenic rat expressing green fluorescent protein (GFP) in peripheral nerves provides a new hindlimb model for the study of nerve injury and regeneration.

BACKGROUND: In order to evaluate nerve regeneration in clinically relevant hindlimb surgical paradigms not feasible in fluorescent mice models, we developed a rat that expresses green fluorescent protein (GFP) in neural tissue. METHODS: Transgenic Sprague-Dawley rat lines were created using pronuclear injection of a transgene expressing GFP under the control of the thy1 gene. Nerves were imaged under fluorescence microscopy and muscles were imaged with confocal microscopy to determine GFP expression following sciatic nerve crush, transection and direct suturing, and transection followed by repair with a nerve isograft from nonexpressing littermates. RESULTS: In each surgical paradigm, fluorescence microscopy demonstrated the loss and reappearance of fluorescence with regeneration of axons following injury. Nerve regeneration was confirmed with imaging of Wallerian degeneration followed by reinnervation of extensor digitorum longus (EDL) muscle motor endplates using confocal microscopy. CONCLUSION: The generation of a novel transgenic rat model expressing GFP in neural tissue allows in vivo imaging of nerve regeneration and visualization of motor endplate reinnervation. This rat provides a new model for studying peripheral nerve injury and regeneration over surgically relevant distances.