Recent researches have showed that neural stem cells be isolated not only in the embryonic nervous system but also in adult nervous system. Neural stem cells have some capacity for self-renewal, migration and can differentiate into neurons, astrocyte and oligodendrocyte. This provides a basis in therapy of degenerative diseases and functional recovery of the central nervous system injury. Also helps in the study of determining the postmortem interval ( PMI) and postmortem injury. Distribution, biological characteristic, identification and the factors effecting the proliferation, differentiation and migration with reference to therapy of neural stem cells and applications in forensic pathology are reviewed.

Objective To Study the expression of apo E protein changed in different wound age and position of the experimental traumatic brain injury(TBI) in rat. Methods The animal model of cerebral contusion was established by impact to the parietal lobe with a free fall weight,observed the changes of apo E in different wound age (0.5h、2h、6h、12h、24h、3d、7d、14d). The results were measured quantitatively with computer imaging analysis system. Results In cortex apo E-positive neurons definitely detected in 0.5h after brain injury, reaching the peak in 3d, then it shows the gradual decrease from 3d to 14d; In hippocampus apo E-positive neurons definitely detected in 0.5h after brain injury, reaching the peak in 3d in CA1 section and 24h in CA2～CA4. Then it shows the gradual decrease. We found the expression of apo E protein in CA1 section is stronger than others. Conclusion The location and intersity of the immunoreactivity of apo E protein changed at the different stages after TBI. These changes observed in the present study might be used for determination of injury time,early diagnosis and distinguish antemortem and postmortem brain injury in forensic medicine.

Objective To explore the influence of delineator and contouring criteria training on the delineation of the tumor bed and whole breast target after breast-conserving surgery.Methods Twelve brcast cancer patients after breast conserving surgery were selected.Tumor bed marked by clips was defined as gross target volume 1 (GTV1),tumor bed formed by seroma was defined as GTV2 and the whole breast was defined as clinical target volume (CTV).Five junior radiation oncologists first delineated GTV1,GTV2 and CTV for each patient following their own criteria.After contouring criteria training,they then delineated GTV1,GTV2 and CTV for the same group of patients again.The differences of the volumes of GTV1,GTV2 and CTV before and after training among different delineators were compared.One-way ANOVA or matching t-test was performed.Results The inter-delineator variability on GTV1,GTV2 and CTV delineation before training was statistically significant (F =11.16,7.54 and 3.78,P =0.000,0.000 and 0.009).After training,the inter-delineator variability on GTV1 and GTV2 delineation had statistical significance (t =4.78 and 4.24,P =0.002 and 0.005),but the inter-delineator variability on CTV delineation had no statistical significance (t =1.52,P =0.209).The coefficient of variance of the GTV1,GTV2 and CTV before and after training was significantly different (t =3.14,2.81,2.70,P =0.009,0.017 and 0.021).The matching index of GTV1,GTV2 and CTV before and after training was significantly different (F =16.08,8.61,8.48,P =0.000,0.000 and 0.000).Conclusions In delineating the target of breast cancer,application of the criteria of target delineation can reduce the difference among the delineators,especially for CTV.

Tree shrews have an excellent visual system, their cones accounted for 96%of the photorecepter cells, so that their color vision and stereo vision are well developed.With their rich resources and low cost, tree shrews have been considered as an ideal animal model in eye research in comparative medicine and genomics research.The ophthalmological research on tree shrew mainly focused on the establishment of myopia model, as well as the changes in myopic sclera and choroids, and the basic studies of their retina, optic and visual cortex.This paper reviewed the basic ophthalmological re-search of tree shrew.

BACKGROUND: Hepatic oval cells (HOCs) possess the potential of self-renewal, replication, and clone, proliferation and differentiation into mature hepatocytes under a certain condition. HOCs can be used as biomaterial for constructing biological artificial liver in vitro, employed for in vivo transplantation, as well as for tissue engineering as seed cells. HOCs can be widely used for improving clinical treatment of liver diseases. OBJECTIVE: To establish adult Wistar rat models of HOC proliferation, to perform/n vitro isolation and culture of HOCs, and to study the possibility of induction and differentiation of HOCs into hepatucytes. DESIGN: Observational study. SETTING: Institute of Gastroenterology, Nanfang Hospital, Southern Medical University. MATERIALS: Experiments were performed at the Laboratory of Institute of Gastroenterology of Nanfang Hospital from December 2003 to February 2006. Thirty-six healthy male Wistar rats aged 3-4 months (150-200 g) were provided by Experimental Animal Center of Southern Medical University. METHODS: Male Wistar rats were orally fed with ethionine received two-thirds partial hepatectomy (2/3 PH). HOCs were harvested and purified by two-steps perfusion and Percoll density gradient centrifugation, and then cultured in vitro and induced with hepatocyte growth factor (HGF), oncostatin M (OSM) and fibroblast growth factor-4 (FGF4). MAIN OUTCOME MEASURES: Identification and differentiation of HOCs. RESULTS: The concentration of HOCs was about 1.34×108 L-1 in each rat model after in vitro isolation. These cells were round, oval or polygon, about 1/6 1/3 the size of normal hepatocytes. The nucleus-cytoplasm ratio was relatively large. After 2 weeks, clone-like proliferation of HOCs could be observed. Laser scanning confocal microscopy indicated positive expression of stem cells markers Thy-1 and C-kit in cytoplasm and membrane of HOCs. Immunocytochemistry demonstrated positive stem cells marker alpha fetoprotein (AFP) in cytoplasm of HOCs. HOCs can stably passage and its shape gradually changed after inducing with HGF, OSM and FGF4. HOC volume became larger and HOCs lost their ability of sticking to the wall of culture flask. Apparent positive stain of cytoplasm albumin (Alb) was detected 14 days after induction, and the positive ratio increased along with the extension of inducing duration. Results of cytochemistry indicated a brown or black deposit after glucose-6-phosphotase (G-6-P) staining and red particles after periodic acid-Schiff (PAS) staining. CONCLUSION: Adult Wistar rat models of HOC proliferation are replicated by ethionine feeding combined with 2/3 PH. HOCs can be obtained through collagenase perfusion and Percoll density gradient centrifugation. Rat HOCs can be passaged and cultured in vitro. Under a certain condition, HOCs can be induced and differentiated into hepatocytes.

Objective To preliminarily explore the feasibility of tree shrew as a new kind of animal model in research of amblyopia,to discuss the primary visual cortex plasticity mechanism of form deprivation in tree shrew,and to provide a theoretical basis for further understanding the mechanism of amblyopia formation and recovery.Methods Sixty 30-days old tree shrews were divided into five groups,12 in each group:the group A had the right eye sutured for 1 month;the group B had the right eye sutured for 2 months;the group C had the left eye sutured for 1 month and then opened and the righ eye was sutured for 1 month,in other words,the group C was performed by alternating suture;the tree shrews of control group 1(D1) were in the same age as the the group A,but fed in normal breedingenvironment;the tree shrews of control group 2(D2) were at the same age of groups B and C,but fed with a normal diet.Samples of the visual cortex were taken after the completion of modeling,and were processed to observe the histology and ultrastructure of the visual cortex,the neuron apoptosis,and the c-fos protein expression in the tree shrews of different groups.Results Damages to different degrees were found by histological and electron microscopic examination of the visual cortex in each experimental group,and they were more obvious in the group sutured for 2 months.TUNEL staining showed that there were no significant differences between the apoptosis in the experimental and control groups.The expression of c-fos mRNA and protein in the experimental groups was decreased,and it was the lowest in the group sutured for 2 months.There was a small increase in the c-fos expression after the alternate suture,and no significant difference of c-fos expression was found in the control groups.Conclusions Different degrees of deprivation amblyopia lead to different histopathological changes.There is a plasticity in the neurons affected by amblyopia.Tree shrew can be used as an ideal animal model for the studies of form deprivation amblyopia.

The finite element method is a new method to study the mechanism of brain injury caused by blunt instruments. But it is not easy to be applied because of its technology barrier of time-consuming and strong professionalism. In this study, a rapid and quantitative evaluation method was investigated to analyze the craniocerebral injury induced by blunt sticks based on convolutional neural network and finite element method. The velocity curve of stick struck and the maximum principal strain of brain tissue (cerebrum, corpus callosum, cerebellum and brainstem) from the finite element simulation were used as the input and output parameters of the convolutional neural network The convolutional neural network was trained and optimized by using the 10-fold cross-validation method. The Mean Absolute Error (MAE), Mean Square Error (MSE), and Goodness of Fit ( R ²) of the finally selected convolutional neural network model for the prediction of the maximum principal strain of the cerebrum were 0.084, 0.014, and 0.92, respectively. The predicted results of the maximum principal strain of the corpus callosum were 0.062, 0.007, 0.90, respectively. The predicted results of the maximum principal strain of the cerebellum and brainstem were 0.075, 0.011, and 0.94, respectively. These results show that the research and development of the deep convolutional neural network can quickly and accurately assess the local brain injury caused by the sticks blow, and have important application value for understanding the quantitative evaluation and the brain injury caused by the sticks struck. At the same time, this technology improves the computational efficiency and can provide a basis reference for transforming the current acceleration-based brain injury research into a focus on local brain injury research.
Brain ; Brain Injuries ; Computer Simulation ; Finite Element Analysis ; Humans ; Neural Networks, Computer