ABSTRACT
BACKGROUND: Super-resolution reconstruction has been extensively studied and used in many fields,such as medical diagnostics,military surveillance,frame freeze in video,and remote sensing.OBJECTIVE: In order to obtain high-resolution magnetic resonance images,gradient magnetic field is required and the signal-to-noise will be reduced due to the decrease in voxel size with traditional scan.The present study used a self-adaptive regularized super-resolution reconstruction algorithm to acquire high-resolution magnetic resonance images from four half-pixel-shifted low resolution images.METHODS: The least squares algorithm was used as a cost function.The dedvative of the cost function was calculated to obtain an iterative formula of super-resolution reconstruction.In the process of iterative process,the parameter and step size of image resolution were regularized.RESULTS AND CONCLUSION: The new regularization parameter makes cost function of the new algorithm convex within the definition region.The piori information is involved in the regularization parameter that can improve the high-frequency components of the restored image.As shown from the results obtained in the phantom imaging,the proposed super-resolution technique can improve the resolution of magnetic resonance image.
ABSTRACT
BACKGROUND:For treatment of spinal cord injury, exogenous neural stem cell transplantation still faces many problems.Thus, the strategy of supplementary treatment of activating exogenous neural stem cells has been a hot focus.It has been found that lithium chloride can significantly inhibit differentiation and promote proliferation of neural stem cells, whose effects are correlated to Wnt signal pathway.OBJECTIVE:To investigate the effect of lithium on endogenous neural stem cells after spinal cord injury in rats.DESIGN, TIME AND SETTING:The randomized controlled animal study was performed at the Central Laboratory, Zhujiang Hospital from March to August 2008.MATERIALS:A total of 55 adult female Wistar rats were assigned into normal control group(n=5), simple injury group(n=25), and lithium chloride group(n=25).Lithium chloride was purchased from Guanghua, Guangzhou, China.METHODS:In the simple injury group and lithium chloride group, rat models of acute spinal cord injury at T10 segment were made by Allens method.From 1 hour following model induction, rats in the lithium chloride group received 3 mmol/kg per day lithium chloride through intraperithoneal injection.Samples were directly obtained.In the simple injury group, rats received an equal volume of saline.Rats in the normal control group were left intact.24 hours before samples were obtained, rats in each group were intraperitoneally injected with Brdu solution for labeling, once every 8 hours, totally 3 times.Spinal cord at 5 mm from the center of damage region received Brdu, catenin immunohistochemistry.MAIN OUTCOME MEASURES:BrdU-positive cell number and area of catenin-positive expression were measured.RESULTS:There were a few Brdu-positive cells and less expression of catenin in the center canal and adventitia of spinal cord in the normal control group.Many Brdu-positive cells and a little expression of catenin were found in gray matter and ependyma of injury area in the simple injury group 24 hours after model induction, which reached the peak at 1 week, and declined gradually at 2 weeks.Just a few Brdu-positive cells and little expression of catenin existed at 4 weeks.Compared with the simple injury group, there was no difference in Brdu-positive cells and the expression of catenin at 24 hours following model induction in the lithium chloride group.There were more Brdu-positive cells and the expression of catenin in the center canal and adventitia of spinal cord at 1 week(P
ABSTRACT
Objective: To evaluate the effect of platelet activating factor(PAF) antagonism on the blood content in the random survival flap. Methods: A lipophilic PAF receptor antagonist BN52021 was administered to treat flaps through a local subcutaneous injection route 30 min prior to transplantation. The flaps were imaged in situ by a gamma camera. Results: The PAF receptor antagonist significantly augmented the accumulation of radioactivity of middle and end part within treated flaps( P