X-irradiation for inhibiting glial scar formation in injured spinal cord

X-irradiation has a beneficial effect in treating spinal cord injury. We supposed that X-irradiation could improve the microenvironment at the site of a spinal cord injury and inhibit glial scar formation. Thus, this study was designed to observe the effects of 8 Gy X-irradiation on the injury site at 6 hours and 2, 4, 7, and 14 days post injury, in terms of improvement in the microenvironment and hind limb motor function. Immunohistochemistry showed that the expression of macrophage marker ED-1 and the area with glial scar formation were reduced. In addition, the Basso, Beattie and Bresnahan score was higher at 7 days post injury relative to the other time points post injury. Results indicated that X-irradiation at a dose of 8 Gy can inhibit glial scar formation and alleviate the inflammatory reaction, thereby repairing spinal cord injury. X-irradiation at 7 days post spinal cord injury may be the best time window.

FUNCTIONAL AND STRUCTURAL RECOVERY OF INJURED SPINAL CORD FOLLOWING DELAYED X-IRRADIATION IN RATS

Objective To test the hypothesis that delayed X-irradiation can enhance the functional and structural recovery of the injured spinal cord in rats. Methods Seventy Sprague-Dawley rots were randomly divided into two groups, 35 rats in each. The control group sustained a one-minute clip compression （ force of clip was 30 g） injury of the spinal cord at the T2 level, without X-irradiation. The experimental group received X-irradiation 14 days after injury. Neurological function was assessed by the modified Tarlov method, including hind limbs movement, inclined plane, and pain withdrawal. These tests were performed in a blinded fashion at 3, 7, 14, 21, 28, 35, and 42 days after injury. At 43 days after injury, histological examination of the injured spinal cord was performed following decapitation of the rats. Results Sixty-two rats met the experimental requirements （spinal cord injury was similar）, 32 rats in experimental group and 30 rats in control group. Statistically significant difference was observed between the two groups in hind limbs movement and inclined plane （ P 〈0. 01 ）, but not in the pain withdrawal test. The edema and necrosis areas of injured spinal cords in experimental group were less than those in control group, and axons in experimental group were significantly more than those in control group （P 〈0.01）. Conclusion Delayed X-irradiation following spinal cord injury may enhance functional recovery by improving and restoring structural integrity of the injured spinal cord in rats.

Value of mink vomit model in study of anti-emetic drugs

AIM： To establish a new, reliable vomit model of minks METHODS： Adult male minks were randomly divided into 8 groups （n=6）： cisplatin （7.5 mg/kg） intraperitoneal injection （ip） group, copper sulfate （40 mg/kg） intragastric injection （ig） group, apomorphine （1.6 mg/kg） subcutaneous injection （sc） group, and 18 Gy whole-body X-irradiation group, ondansetron injection group （2 mg/kg ip） 30 min later followed by cisplatin （7.5 mg/kg） ip, normal saline （NS） ip injection control group, metoclopramide injection group （4 mg/kg ip） 30 rain later followed by apomorphine （1.6 mg/kg） sc, NS ig control group. The frequency of retching and vomiting was calculated. After behavioral experiment, distribution of 5-HT in the ileum was detected by immunohistologic method. RESULTS： Cisplatin, apomorphine, copper sulfate and X-irradiation administered to minks evoked a profound emetic response in the animals. However, retching and vomiting were significantly inhibited by pretreatment with ondansetron and metoclopramide in cisplatin and copper sulfate groups （P=0.018）. Immunohistologic result showed that 5-HT released from enterochromaffin cells （EC cells） was involved in vomiting mechanism. CONCLUSION： Mink vomit model has a great value in studying the vomiting mechanism and screening new antiemetic drugs.

AUTORADIOGRAPHIC STUDY OF THE ATTRITION OF MIGRATING SCHISTOSOMULA IN THE SKIN OF MICE II.MICE CHALLENGED WITH NORMAL S.MANSONI CERCARIAE AFTER IMMUNIZATION WITH HIGHLY IRRADIATED CERCARIAE

The migratory pattern and attrition of75Se-labelled S.mansoni challenge cercariae in CF1mice immunized 0,1,3, or 5 times with 12kR-or 48kR-irradiated cercariae were investigatedby compressed organ autoradiography.Mice were percutaneously inoculated with 500-1000 cer-cariae for each immunization and with a known count of approximately 90 cercariae at adifferent site for challenge.The skin,lungs,liver,other organs,and catrcass were processedfor autoradiography.Hepatic and mesenteric perfusions for worm collection were alsosampled from day 19 through 34.In naive tnice,25% of challenge cercariae died in theskin.Skin attrition of challenge cercariae in mice immunized with 12kR-irradiated cercariaewas 43% with 1 immunization,54% with 3,and 58% with 5,whereas in mice immunized with48kR-irradiated cercariae,skin,attrition was48% with 1,63% with 3,and 76% with 5 immunni-zations.In all immunized mice,a high percentage of migrating sehistosomula died in the skinwithin 24 hours of a challenge infection.Utilizing autoradiography,it was found that thesilver foci created by single labelled worms were difficult to differentiate from those of pairedworms.This study documents the induction of acquired resistance against a challenge infectionin the skin by vaccination with highly irradiated cercariae,with the degree of attemtation ofimmunizing cercariae and the number of immunizations being closely related to the attritiotn.rate in the skin.Finally,we discuss the contradictory views concerning the site of attritiotn ofchallenge cercariae.

New color centers and recombination luminescence of SrFCl:Eu^(2+) crystal

X-ray storage phosphors MFX:Eu2+ （M=Ca, Sr, Ba; X=Cl, Br, I） have been studied extensively, because they exhibit photostimulated luminescence （PSL） properties and offer an alternative to conventional X-ray imaging technology. Color centers play a very important role in the PSL process; much work on the color centers in this kind of materials has been done, such as the formation and optical properties of F centers, V centers and oxygen defects in BaFCl and BaFBr crystals.The study of color centers provides direct evidence for the understanding of the PSL process and is helpful for the practical application of these materials. New color centers and PSL of BaFCl: Eu2+[8] and BaFBr: Eu2+[9] crystals have been reported. New centers in SrFCl: Eu2+ and BaFI: Eu2+