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Li-ming Guan, Xi-Xun Qi, Bin Xia, Zhen-hua Li, Yu Zhao and Ke Xu

Object

In this paper, the authors' aim was to use CT perfusion imaging to evaluate the early changes in tumor microcirculation following radiosurgery in rat C6 brain gliomas.

Methods

C6 glioma cells were inoculated into the right caudate nucleus of 25 Wistar rats using a stereotactic procedure. Tumor-bearing rats were randomly divided into 2 groups (tumor group and treatment group). Rats in the treatment group received maximal doses of 20 Gy delivered by the X-knife unit 16 days postimplantation. Computed tomography perfusion imaging was performed in all rats 3 weeks after tumor implantation prior to death and histopathological analysis.

Results

Hypocellular regions and tumor edema were increased in the treatment group compared with the tumor group. Parameters of CT perfusion imaging including cerebral blood volume (CBV) and mean transit time (MTT) of the tumors as well as the permeability surface area (PSA) product in the tumor-brain districts were decreased in the treatment group compared with the tumor group (p < 0.05). Although microvascular density (MVD) in the periphery of the tumors in the treatment group was higher than that in the normal contralateral brain (p < 0.05), MVD of the tumors in the treatment group was less than that in the tumor group (p < 0.01). There was a positive correlation between cerebral blood flow (CBF) and MVD as well as CBV and MVD in the center and periphery of tumors in both groups (p < 0.05).

Conclusions

A decrease in the perfusion volume of rat C6 brain gliomas was observed during the acute stage following X-knife treatment, and CBF and CBV were positively correlated with MVD of rat C6 brain gliomas. Thus, CT perfusion imaging can be used to evaluate the early changes in tumor microcirculation following radiosurgery.

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Wang Gai Qing, Yang Qi Dong, Tang Qing Ping, Li Guang Lai, Li Dong Fang, Hu Wei Min, Lian Xia and Pei Yu Heng

Object

Brain edema formation following intracerebral hemorrhage (ICH) appears to be partly related to erythrocyte lysis and hemoglobin release. An increase of brain water content was associated with an increase of brain iron, which is an erythrocyte degradation product. Expression of AQP4 is highly modified in several brain disorders, and it can play a key role in cerebral edema formation. However, the question whether AQP4 is regulated by drugs lacks reliable evidence, and the interacting roles of iron overload and AQP4 in brain edema after ICH are unknown. The goal of this study was to clarify the relationship between iron overload and AQP4 expression and to characterize the effects of the iron chelator deferoxamine (DFO) on delayed brain edema after experimental ICH.

Methods

A total of 144 Sprague-Dawley rats weighing between 250 and 300 g were used in this work. The animals were randomly divided into 4 groups. The ICH models (Group C) were generated by injecting 100 μl autologous blood stereotactically into the right caudate nucleus; surgical control rats (Group B) were generated in a similar fashion, by injecting 100 μl saline into the right caudate nucleus. Intervention models (Group D) were established by intraperitoneal injection of DFO into rats in the ICH group. Healthy rats (Group A) were used for normal control models. Brain water content, iron deposition, and AQP4 in perihematomal brain tissue were evaluated over the time course of the study (1, 3, 7, and 14 days) in each group.

Results

Iron deposition was found in the perihematomal zone as early as the 1st day after ICH, reaching a peak after 7 days and remaining at a high level thereafter for at least 14 days following ICH. Rat brain water content around the hematoma increased progressively over the time course, reached its peak at Day 3, and still was evident at Day 7 post-ICH. Immunohistochemical analysis showed that AQP4 was richly expressed over glial cell processes surrounding microvessels in the rat brain; there was upregulation of the AQP4 expression in perihematomal brain during the observation period, and it reached maximum at 3 to 7 days after ICH. The changes of brain water content were accompanied by an alteration of AQP4. The application of the iron chelator DFO significantly reduced iron overload, brain water content, and AQP4 level in the perihematomal area compared with the control group.

Conclusions

Iron overload and AQP4 may play a critical role in the formation of brain edema after ICH. In addition, AQP4 expression was affected by iron concentration. Importantly, treatment with DFO significantly reduced brain edema in rats and inhibited the AQP4 upregulation after ICH. Deferoxamine may be a potential therapeutic agent for treating ICH.

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Wen-qing Huang, Shi-ju Zheng, Qing-sheng Tian, Jian-qing Huang, Yu-xia Li, Qing-zhong Xu, Zi-jun Liu and Wen-cui Zhang

✓ The authors present a statistical survey of the general incidence, age distribution, and preferential sites of 25,122 tumors of the central nervous system (CNS), from 12 centers in China. Of these tumors, 22,457 were intracranial and the rest intraspinal.

Of the 22,457 intracranial neoplasms collected, tumors of neuroepithelial tissue comprised 43.85%, meningiomas 16.58%, tumors of nerve sheath cells 9.5%, pituitary adenoma 9.52%, congenital tumors 8.46%, secondary tumors 6.8%, vascular malformations and tumors 3.82%, and primary sarcomas 0.72%. Neuroepithelial and meningeal tumors occurred first and second in all series, but the other tumors varied in frequency. There was a higher incidence of nerve-sheath tumors in southern than in northern regions. The age distribution of Chinese patients with tumors of the CNS was lower than that of Caucasians: nearly two-thirds (64.57%) had the clinical onset of their tumor between the ages of 31 and 40 years, with the peak incidence at 35 years. Nearly 20% of tumors of the CNS occurred before 20 years of age. The male:female ratio was 1.53:1; the only tumor with a definite preponderance of females over males was the meningioma.

Intraspinal tumors derived from nerve sheaths comprised 47.13% of all tumors within the spinal canal. Meningiomas were second with an incidence of 14.06%, then followed congenital tumors (12.06%) and neoplasms of neuroepithelial tissue (10.83%). Secondary tumors, vascular malformations and neoplasms, and sarcoma were next in order of frequency with 4.6%, 4.5%, and 4.16%, respectively.