AIM: To investigate the relation between the changes of the cerebral microvasculature and the expression of plasminogen activator inhibitor-1 (PAI-1) in ischemic focal and perifocal areas after 2 hours focal cerebral ischemia with reperfusion in rats. METHODS: The changes of cerebral microvascular structure were observed by optical microscope and electric microscope, the expression of PAI-1 were assessed by immunohistochemical staining, Western blotting in ischemic focus and perifocal areas after focal cerebral ischemia with reperfusion. RESULTS: The edema of extra-cellular matrix and the hemorrhage of extravessels in ischemic focus and perifocal areas were most severe, and degradation and the defect of basement membrane were also observed after 6 hours and 3 days reperfusion following focal cerebral ischemia. The expression of PAI-1 decreased significantly compared with control group (P

Objective To evaluate the anatomic changes and dosimetric variations of patients with nasopharyngeal carcinoma (NPC) during the course of simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) by comparison of the dosimetric differences with or without replanning.Methods Twelve cases with NPC treated with SIB-IMRT underwent repeated CT scans after 20- 25 fractions of the initiation of therapy.The original treatment plan ( Plan1 ) based on the first CT scan ( CT1 ) and the second IMRT plan (Plan 2) based on the second CT scan (CT2) were calculated with an inverse planning system (Pinnacle3,Philips Medical System).In addition,the hybrid IMRT plan,Planl (CT2),was generated by deformable registration with MIMVISTA software,and the doses in Plan 1 ( CT1 ) and Plan 2 ( CT2 ) were accumulated based on CT2.The dosimetric differences were compared among the Plan 1 ( CT1 ),Plan 1 (CT2) and Plan 1 + 2(CT2).Results Compared with CT1,the mean volumes of the right and left parotid glands in the CT2 were significantly smaller by ( 24.6 ± 11.9 ) ％ and ( 35.1 ± 20.1 ) ％,respectively.Compared with Plan 1 ( CT1 ),the dose received by 95％ of the target ( D9s ) to PGTV,PTV1 and PTV2,and mean dose (D ) to PGTV,and PTV2 were all significantly lower in the Plan 1 (CT2),indicating that the doses to targets decreased without replanning.With repeated CT and replanning after 25 fractions as shown in Plan 1 + 2 (CT2),the doses to targets would be improved.The doses to normal tissue were increased without replanning,although no statistical significance was observed.In 5 of 12 cases,the doses to the spinal cord and brainstem exceeded the constraint without replanning,while the corresponding values decreased with replanning.Conclusions During the course of IMRT for cases with NPC,the volumes of the targets and parotid glands decrease significantly.Mid-treatment CT scanning and replanning should be recommended to ensure adequate doses to the targets and safe doses to the normal tissues.

genes related to pancreatic cancer was mainly associated with biological process,cellular location,molecular function,which suggested the development of pancreatic cancer was caused by multiple genes.