Aspirin can effectively prevent ischemic cerebrovascular disease. However, as the existence of "aspirin resistance" phenomenon, ischemic events still occur in some patients during the aspirin treatment. This article mainly reviews the mechanisms, screening methods and treatment measures of aspirin resistance.

Objective To investigate the related risk factors for small artery occlusion (SAO) and its 2 subtypes. Methods The clinical and imaging data in 291 patients with first-ever stroke who met the TOAST criteria of large artery atherosclerotic stroke (LAA) or SAO were collected from the Nanjing Stroke Registry Prog-am from December 2009 to November 2010. All the patients were divided into a LAA group (n = 120) and a SAO group (n = 171). The latter was redivided into either a lacunar infarction with ischemic leukoaraiosis (ILA) subgroup (n = 84)or an isolated lacunar infarction (ILI) subgroup (n = 87). The risk factors of the LAA group and SAO group and its subgroups were compared. Multivariate logistic regression analysis was conducted and the independent risk factors were screened. Results The mean age in the SAO group was larger than that in the LAA group. The proportion of the patients with hypertension and the serum homocysteine (Hcy) level were significantly higher than those in the LAA group (all P ＜0. 05). Multivariate logistic analysis showed that the advanced age (odds ratio, [OR] = 1.041,95% confidence interval [CI] 1.02-1.06, P = 0.045), hypertension (OR = 2. 912,95% CI 1. 11-6. 46, P =0. 031) and increased plasma Hcy (OR = 1. 109, 95% CI 1. 11-1. 32, P =0. 001) were the independent risk factors for SAO. The advanced age (OR = 1. 047,95% CI 1.00-1.09, P = 0.043), hypertension (OR = 2. 632, 95% CI 1.08-6.41, P= 0.033) and increased plasma Hcy (OR = 1. 211, 95% CI 1. 11-1. 32, P ＜0. 001) were the independent risk factors for ILA, while the hypercholesterolemia (OR =0. 136, 95% CI 0. 05-0. 37, P ＜0. 001) was the independent risk factor for ILI. Conclusions The advanced age, hypertension and increased plasma Hcy level may play important roles in the pathogenesis of SAO. The hypercholesterolemia is an independent risk factor for ILI, while advanced age, hypertension and increased plasma Hcy level are the independent risk factors for ILA.

Objective To study the lesion patterns of hemorrhagic type of moyamoya disease (MMD) in adults. Methods Seventy-two consecutive cases of hemorrhagic type of MMD, confirmed by digital cerebral angiography in Jinling hospital between January 2004 and February 2010, were retrieved from the Nanjing Stroke Registry Program. MMD patients were classified according to the hemorrhagic sites into 4 types: non-thalamic parenchymal, thalamic, primary ventricular and subarachnoid. The ipsilateral anterior choroidal artery and posterior communicating artery (AChA-PComA) were evaluated by the modified Morioka's 3-points grading system: normal or mild to moderate dilation, severe dilation with abnormal extension and non-visualization. The relationship between lesion patterns and the angiographic findings was analyzed. Results In the stage of normal or mild to moderate dilation of AChA-PComA, non-thalamic parenchymal hemorrhage was the more frequent type (51.6%, 16/31 ;Z = -3.266,P =0.001 ), and there was a high incidence of intrastriatal hemorrhage occurred (22.6%, 7/31 ). In the stage of severe dilation with abnormal extension, intraventricular hemorrhage was most common ( 58.8%, 20/34 ;Z = -2.696 ,P =0.008). In addition, posterior circulation subarachnoid hemorrhage (SAH) was associated with a higher grade of AChA-PComA than anterior circulation SAH (Z = -4.655 ,P ＜ 0.01 ). Furthermore, posterior circulation SAH was the only type of SAH in the stage of non-visualization(9.7% ,7/72; x2 =42.999,P ＜0.01 ). Conclusion In adult patients with MMD, different subtypes of hemorrhagic stroke were associated with angiographic changes of AChA-PComA, and the angiographic characteristics may predict the location of hemorrhage.

Objective To investigate the relationship between isehemic lesion patterns and Suzuki's vessel grades in adult moyamoya disease(MMD).Methods Forty-four consecutive MMD patients,12 with transient ischemic attack(TIA),30 with cerebral infarct(CI)and 2 with combined TIA and CI,who were diagnosed in Jinling hospital between January of 2004 and July of 2009,were retrieved from Nanjing Stroke Registry Program.Ischemic lesions patterns of CI type of MMD were further divided into two paired subgroups including subcortical subgroup versus cortical subgroup, and subgroup of anterior cerebral circulation versus subgroup of posterior cerebral circulation.In addition,the ipsilateral vessel grades of all symptomatic hemispheres were evaluated by Suzuki's 6-grade system according to the results of cerebral angiography of internal carotid arteries.The percentage of number of hemispheres with ischemic events among the paired groups,including TIA group versus CI group,subcortical subgroup versus cortical subgroup,and subgroup of anterior cerebral circulation versus subgroup of posterior cerebral circulation,were analyzed respectively with changes of the Suzuki's grading.Results For above-mentioned each paired groups.the percentage of number of hemispheres with ischemic events was gradually decreased in the former (namely,11/26,2/13,1/8,0 and 0;15/15,9/11,1/7,0 and 0;15/15,10/11,4/7,0 and 0)and increased in the latter(namely,15/26,11/13,7/8,2/2 and 1/1;0,2/11,6/7,2/2 and 1/1;0,1/11,3/7,2/2 and 1/1 ) from grade 2 to grade 6, and the differences were statistically significant (Z = -2. 33 and P =0. 019,Z = - 4.49 and 0. 00, Z = - 3.66 and 0. 01, respectively ). Moreover, the mean value of Suzuki' s grade was lower in the former than the latter for above-mentioned three groups (2. 29 vs 2. 97, 2. 44 vs 4. 18 and 2. 62 vs 4. 13, respectively). Conclusion The ischemic lesion patterns of adult MMD is changing with the change of Suzuki' s vessel grading. The higher the Suzuki' s grade, the greater the likelihood of ischemic lesions involving the cortical areas of posterior cerebral circulation.

BACKGROUND:Large numbers of experimental data have confirmed that bone marrow mesenchymal stem cel s have a positive therapeutic effect on cerebral ischemia-reperfusion injury, but there are few reports about intravenous administration of bone marrow mesenchymal stem cel conditioned medium in the treatment of stroke.
OBJECTIVE:To investigate the effects of the conditioned medium of rat bone marrow mesenchymal stem cel s on the recovery of neurological function in rats after cerebral ischemia-reperfusion injury.
METHODS:The bone marrow mesenchymal stem cel s were isolated from rat bone marrow. When cel s at passage 2 or 3 reached 90%confluence, the original culture medium was removed. Then the cel s were cultured in serum-free DMEM for 18 hours. After that, the culture solution was col ected as the conditioned medium of rat bone marrow mesenchymal stem cel s. Adult rats were subjected to 2 hours of right middle cerebral artery occlusion. Ischemia-reperfusion injury rats were randomly assigned to three groups:control group, simple culture medium group and conditioned medium group, and respectively given injection of normal saline, DMEM, conditioned medium (10 mL/kg) via the tail vein at 2, 24, 48 hours after operation.
RESULTS AND CONCLUSION:There was no difference in the behavioral tests among the three groups at postoperative 2 hours (P>0.05). Compared with the control and simple culture medium group, neurological impairment was significantly improved in the conditioned medium group at postoperative 1, 3, 5 days (P<0.05), but there was no significant difference between the control and simple culture medium groups. At postoperative 5 days, brain edema was significantly eased in the conditioned medium group in comparison to the control and simple culture medium groups (P<0.05), and there was also no difference between the latter two groups (P>0.05). These results suggest that rat bone marrow mesenchymal stem cel s-conditioned medium via intravenous administration can significantly ease brain edema and improve the neurologic function after cerebral ischemia-reperfusion injury.