ABSTRACT
Objective To establish the model for periventricular leukomalacia(PVL) by intracerebral injection of 3-nitropropionic acid (3-NPA) and explore realistic model for concerned studies and investigate the diagnostic method with magnetic resonance imaging (MRI) examination. MethodsSprague-Dawley rat pups of both sexes at the age of postnatal day 5 (P5) were randomized and divided into two groups: NPA group and PBS group , and they were injected the same volume of 3-NPA and PBS with a tip located at the corpus callosum above the left ventricle by stereotaxis instrument, respectively. One day (P6), two days (P7), three days (P8) and nine days (P14) after injection, the injections were transcardially perfused and brains were collected. Then sections of brains were undertaken HE staining; growth and the time of opening eyes of the rats in the two different groups were observed and compared. Neurobehaviorai activity and memory tests were performed on postnatal day 29 (P29) and day 30 (P30). MRI examination was performed on postnatal day 30 (P30). ResultsMore weight increase and slower opening eye time were found in the NPA group compared with PBS group (P < 0.05). In the NPA group, sub-cortical and periventricular white matter rarefaction were observed by HE staining on P6, P7 and P8, significant lateral ventricle enlargement was found on P14, while the same changes were not found in the PBS group, and no histological changes in gray matter were noted in both groups. The outcomes of neurobehavioral tests of NPA group were much more abnormal compared with the PBS group (P < 0.05). MRI examination disclosed the signal changes of brain tissue is worse in the NPA group than that of the PBS group in muscle strength of limbs, autocinesis, capability and white matter. ConclusionsThe model for PVL induced by intracerebral injection of 3-NPA is characterized by damage to the periventricular white matter. The model can stimulate the pathologic change factually in vivo. The neurobehavioral movement is consistent with.clinical symptom. It can be used as a model to investigate some related disease. MRI examination is a feasible diagnostic method to show anatomic changes of white matter injury of the brain.
ABSTRACT
Automatic gene-chip image grid localization is an essential task for gene-chip image analysis. Now an method based on profiles of gene-chip image is proposed. Using the differences between two profiles after filtration by arithmetic mean method, we can easily find the local grayscale minimum between two probe spots, then the probe spots are automatically located. The experiments show that the new approach correctly locates the probes while giving protection against noise affection robustly. Grid location