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Background: After peripheral nerve injury, there is an increase in calcium concentration in the injured nerves. Our previous publications have shown that increase in calcium concentration correlated well with degree of nerve injury and that local infusion of calcitonin has a beneficial effect on nerve recovery. Schwann cells play a pivotal role in regeneration and recovery. We aim to examine cultured Schwann cell survivals in various concentrations of calcium-containing growth media and the effect of calcitonin in such media. Methods: To establish baseline in postinjury state, crush injury was induced in male Sprague-Dawley rats' sciatic nerves. Extra- and intraneural calcium concentrations were measured. To study Schwann cell survival, uninjured sciatic nerve segment was harvested and cultured in media containing various amounts of calcium. To study the effect of calcitonin, nerve harvest and culture were done in four additional media: (1) normal control, (2) normal control with calcitonin, (3) high calciummedium, and (4) high calcium medium with calcitonin. Schwann cells were studied and analyzed under fluorescent conditions. Results: With increasing calciumconcentration, there was a significant decrease in the number of Schwann cells. For the experimental groups, in which calcitonin had been added to the growth medium, there were similar amounts of Schwann cells present in both high and low calcium-containing medium. Conclusion: Schwann cells are sensitive to increasing calcium concentration. Calcitonin counteracts the detrimental effects of high calcium on Schwann cell survival. This can have significant future clinical implications for patients with peripheral nerve injuries. [ABSTRACT FROM AUTHOR]

Background Histological analysis remains a cornerstone approach for the investigation of peripheral nerve regeneration. This study investigates a newly recognized histological difference between peripheral and central zones within the regenerating nerve trunks. Purpose The purpose of the study was to determine if the nerve axonal area (NXA) in regenerating peripheral nerves differs within central and peripheral areas, when viewed in cross-section. Methods A total of 14 rats were divided into two groups, and subjected to different injuries to the right sciatic nerve. Group 1: Transection injury with immediate repair. Group 2: Crush injury without any treatment. The left sciatic nerve was left uninjured and served as a control in each rat. Following 4 weeks of recovery, nerve trunk cross-sections were prepared. Computerized techniques were then employed to divide nerve sections into central and peripheral zones and calculate corresponding NXA values for subsequent statistical analysis. Results NXA of injured nerves was greater within peripheral as compared with the central zones, independent of injury type (p < 0.05). No statistically significant difference existed within the control groups or between the injury methods with regards to NXA regeneration extent. Conclusion NXA in regenerating peripheral nerves was greater in the peripheral zones than within the central zones. [ABSTRACT FROM AUTHOR]

The commonly used methods to quantify axon numbers and mean area include manual and semiautomated procedures. The authors introduce a new fully automated method of morphometric analysis using ImageJ and Paint.net software to improve efficiency and accuracy. A total of six rat sciatic nerves were examined for their axon numbers and mean axon area by comparing the manual method or semiautomated MetaVue method with the new ImageJ method. It was observed that the number of axons for manual counting and ImageJ were 4,630 ± 403 and 4,779 ± 352, respectively, and the difference was not statistically significant (p > 0.5, t-test). The mean axon area measured was 13.44 ± 2.62 µm² for MetaVue and 8.87 ± 0.78 µm² for ImageJ, respectively, and the difference was statistically significant (p < 0.01, t-test). The standard error and coefficient of variation of MetaVue were 1.07 and 0.195; and for ImageJ were 0.32 and 0.087. The authors conclude that their new approach demonstrates improved convenience, time efficiency, accuracy, and less operator error or bias. [ABSTRACT FROM AUTHOR]

Background After nerve injury, an influx of calcium exceeds the homeostatic capacity, which damages peripheral nerves. Previous studies identified that following nerve crush, function improves as calcium levels normalize. Methods Electrophysiological analysis was performed to measure the compound muscle action potential of 15 patients' damaged nerves. These samples were evaluated for calcium level and also stained with a Luxol fast blue and neurofilament antibodies to evaluate the myelin sheath and neurofilaments of the nerves. Based on the Sunderland scale, we identified three exclusive types of peripheral nerve injury groups. Results There was a correlation between histopathological damage and calcium levels of 0.81 (p < 0.005). The average relative fluorescence units (RFUs) was 235.28 ± 19, which corresponds to 5.3 x 10-7 M of calcium, five times the normal value. Conclusion Our study shows promising clinical implications via faster pathology results by the RFU technique. This approach of calcium staining, though still in clinical trials, offers significant clinical application, allowing physicians to get the clinically diagnostic nerve injury degree faster and will also facilitate better strategies for further treatment or future surgeries. [ABSTRACT FROM AUTHOR]

Despite recent advances in microsurgery, the incidence of thrombosis of repaired digital vessels following crush injury is higher than that of uncrushed arteries. The purpose of this study was to evaluate the effects of traumatic crush injury on uncrushed segments of artery adjacent to crushed segments. Sprague-Dawley rat-tail arteries were crushed for 1 hour by 30 pounds of force at two separate 3-mm-wide segments, with 10 mm of uncrushed artery between segments. Luminal size of the uncrushed segments decreased progressively over the first 12 hours, with a significant reduction by 4 hours postcrush. The condition of the arteries continued to deteriorate until, by 24 hours postinjury, they had been denuded of endothelium, and smooth muscle damage had occurred. Untreated vasospasm following a multiple-level crush injury therefore results in progressive endothelial and intimal damage and thrombosis in the intervening healthy uncrushed segments of artery. This article discusses the implications of these findings. [ABSTRACT FROM AUTHOR]