Validation of White-Matter Lesion Change Detection Methods on a Novel Publicly Available MRI Image Database

Changes of white-matter lesions (WMLs) are good predictors of the progression of neurodegenerative diseases like multiple sclerosis (MS). Based on longitudinal magnetic resonance (MR) imaging the changes can be monitored, while the need for their accurate and reliable quantification led to the development of several automated MR image analysis methods. However, an objective comparison of the methods is difficult, because publicly unavailable validation datasets with ground truth and different sets of performance metrics were used. In this study, we acquired longitudinal MR datasets of 20 MS patients, in which brain regions were extracted, spatially aligned and intensity normalized. Two expert raters then delineated and jointly revised the WML changes on subtracted baseline and follow-up MR images to obtain ground truth WML segmentations. The main contribution of this paper is an objective, quantitative and systematic evaluation of two unsupervised and one supervised intensity based change detection method on the publicly available datasets with ground truth segmentations, using common pre- and post-processing steps and common evaluation metrics. Besides, different combinations of the two main steps of the studied change detection methods, i.e. dissimilarity map construction and its segmentation, were tested to identify the best performing combination.     

Estradiol prevents Aβ25 35-inhibited long-term potentiation induction through enhancing survival of newborn neurons in the dentate gyrus

Aim and Methods: Estradiol (E2) is reported to attenuate β-amyloid (Aβ) accumulation and slow the progression of Alzheimer's disease (AD). This study explored the beneficial effect of E2 in AD using histological examination and electrophysiological recording technique in AD model mice created by intracerebroventricular injection of β-amyloid 25–35 (Aβ_25–35). Results: Infusion of Aβ_25–35 reduced the number of newborn neurons in the 2nd week after birth, a critical period for neurite growth, and impaired high-frequency stimulation-dependent long-term potentiation (LTP) induction in perforant path-granular synapses of hippocampal dentate gyrus (DG). Administration of E2 from the 2nd to 4th week after cell birth in Aβ_25–35-mice ameliorated the impairment of newborn neurons and LTP induction in DG. Acute application of E2 failed to increase the newborn neurons and rescue LTP induction in the DG of Aβ_25–35-mice. Conclusions: The effect of E2 in Aβ_25–35-impaired LTP induction depends on its neuroprotection improvement.     

Hydrocephalus after decompressive craniectomy for malignant hemispheric cerebral infarction

Purpose: Several studies have investigated the incidence and risk factors of hydrocephalus after decompressive craniectomy (DC) for malignant hemispheric cerebral infarction. However, the results are controversial. Therefore, the following is a retrospective cohort study to determine the incidence and risk factors of hydrocephalus after DC for malignant hemispheric cerebral infarction. Materials and methods: From January 2004 to June 2014, patients at two medical centres in south-west China, who underwent DC for malignant hemispheric cerebral infarction, were included. The patients’ clinical and radiologic findings were retrospectively reviewed. A chi-square test, Mann–Whitney U-test and logistic regression model were used to identify the risk factors. Results: A total of 128 patients were included in the study. The incidence of ventriculomegaly and shunt-dependent hydrocephalus were 42.2% (54/128) and 14.8% (19/128), respectively. Lower preoperative Glasgow Coma Scale (GCS) score and presence of subarachnoid haemorrhage (SAH) were factors significantly associated with the development of post-operative hydrocephalus after DC. Conclusions: Cerebral infarction patients receiving DC have a moderate tendency to suffer from post-operative hydrocephalus. A poor GCS score and the presence of SAH were significantly associated with the development of hydrocephalus after DC.     

Wnt/β‐catenin signaling mediates the seizure‐facilitating effect of postischemic reactive astrocytes after pentylenetetrazole‐kindling

Ischemia not only leads to tissue damage, but also induces seizures, which in turn worsens the outcome of ischemia. Recent studies have revealed the impaired homeostatic functions of reactive astrocytes, which were thought to facilitate the development of seizures. However, how this phenotype of reactive astrocytes is regulated remains unclear. Here, using pentylenetetrazole (PTZ)‐kindling model, we investigated the roles of reactive astrocytes and their intracellular Wnt/β‐catenin signaling in the ischemia‐increased seizure susceptibility. Our data showed that somatosensory cortical ischemia significantly increased the susceptibility to PTZ‐induced seizure. Genetic ablation of Nestin‐positive reactive astrocytes significantly decreased the incidence and severity of seizures. By using a Wnt signaling reporter mice line Topgal mice, we found that Wnt/β‐catenin signaling was upregulated in reactive astrocytes after ischemia. Depletion of β‐catenin in reactive astrocytes significantly decreased the susceptibility of seizures and the expression of c‐Fos induced by PTZ in the ischemic cortex. Overexpression of β‐catenin in reactive astrocytes, in contrast, significantly increased seizure susceptibility and the expression of c‐Fos. Furthermore, the expression of aquaporin‐4 (AQP‐4) and inwardly rectifying K⁺ channel 4.1 (Kir4.1), two molecules reportedly associated with seizure development, was oppositely affected in reactive astrocytes with β‐catenin depletion or overexpression. Taken together, these data indicated that astrocytic Wnt/β‐catenin signaling accounts, at least partially, for the ischemia‐increased seizure susceptibility. Inhibiting Wnt/β‐catenin signaling may be utilized in the future for preventing postischemic seizures. GLIA 2016;64:1083–1091     

医疗保险状态对急性缺血性脑卒中患者选择静脉内溶栓治疗的影响

目的探索医疗保险状态对急性缺血性脑卒中(AIS)患者选择静脉内溶栓治疗的影响。方法回顾性收集2012年5月至2016年1月收治的符合静脉内溶栓治疗指征的AIS患者293例,根据患者的医疗保险状态分为医保组256例和非医保组37例,比较两组的临床基线资料,并采用Logistic回归分析医疗保险状态与选择静脉内溶栓治疗的相关因素。结果医保组静脉内溶栓177/256例(69.1%);非医保组静脉内溶栓30/37例(81.1%),两组间比较差异无显著性(P=0.136)。医保组患者年龄更大(P0.001),合并有高血压病史(P=0.040)、冠心病史(P=0.008)和既往脑卒中史的比例更高(P=0.002),住院天数明显延长(P0.001),住院总费用增高(P=0.077)。多因素Logistic回归分析提示:高龄(P0.001)、血脂异常(P=0.005)、入院时美国国立卫生研究院卒中量表(NIHSS)评分高(P0.001)、发病至来院时间长(P=0.006)是AIS患者选择接受静脉内溶栓治疗的独立预测因素。在接受静脉内溶栓治疗的患者中,医保组与非医保组的溶栓开始时间差异无显著性(P=0.612)。结论年龄轻、高NIHSS评分、发病时间短且伴有血脂异常的AIS患者更倾向于接受静脉内溶栓治疗,是否有医疗保险不影响患者对静脉内溶栓治疗的选择;无论是否有医疗保险,患者接受静脉内溶栓治疗的开始时间相似;有医疗保险患者住院时间更长,住院总费用更高。     

移植人羊膜间充质干细胞促进脊髓损伤大鼠神经功能恢复

目的研究移植人羊膜间充质干细胞（hAMSCs）是否促进脊髓损伤大鼠神经功能恢复,探索其可能作用机制。 方法60只雌性SD大鼠按照随机数字表法分为磷酸盐缓冲液（PBS）治疗组（30只）和hAMSCs治疗组（30只）。脊髓损伤采用脊髓撞击损伤模型,hAMSCs或PBS立刻移植到离脊髓损伤中心2 mm的头尾两端。免疫荧光检测细胞分化,血管再生和轴突再生。酶联免疫吸附剂测定试剂盒检测脑源性神经营养因子（BDNF）和血管内皮生长因子（VEGF）含量,BBB运动功能评分检测行为学。 结果在脊髓损伤后14 d、21 d和28 d,hAMSCs治疗组BBB评分分别为（8.75±0.701）、（10.375±0.532）和（12.125±0.350）,高于PBS组（6.0±0.463）、（7.25±0.412）和（9.125±0.440）,差异具有统计学意义（P<0.05）。在第7天和第14天,hAMSCs治疗组BDNF表达水平分别为（75.138±4.367）pg/mg和（66.483±4.099）pg/mg,高于PBS组（43.901±3.607）pg/mg和（41.108±3.848）pg/mg,差异具有统计学意义（P<0.05）。在第7天,第14天和第28天,hAMSCs治疗组VEGF表达水平分别为（23.328±2.463）pg/mg,（22.301±2.223）pg/mg和（14.855±1.282）pg/mg,高于PBS组（9.978±1.572）pg/mg,（9.271±1.496）pg/mg和（7.113±1.123）pg/mg,差异具有统计学意义（P<0.05）。hAMSCs治疗组血管数目（17.5±2.102）高于PBS组（6.25±1.750）,差异具有统计学意义（P<0.05）。hAMSCs治疗组小鼠抗5羟色胺阳性神经纤维面积（3486±203.643）和GAP43阳性神经纤维面积（4568.25±253.881）高于PBS组（2070.25±156.344）和（2455.725±314.475）,差异具有统计学意义（P<0.05）。 结论移植hAMSCs能促进脊髓损伤大鼠神经功能恢复,其作用机制可能是通过增加神经营养因子表达,促进血管再生和轴突再生。因此hAMSCs移植是治疗脊髓损伤的理想方法。     

重症患者凝血功能障碍标准化评估中国专家共识

40%以上的重症患者会发生凝血功能障碍,合并凝血功能障碍的重症患者出血不良事件、输血量及病死率可升高4倍以上。早期识别凝血功能障碍并准确评估凝血功能,是尽快纠正凝血功能障碍的前提及保障,但目前国内外尚缺乏如何快速、准确评估重症患者凝血功能障碍的标准。为此,全军重症医学专业委员会联合中国医药教育协会血栓与止血危重病专业委员会组织临床专家共同制定了《重症患者凝血功能障碍标准化评估中国专家共识》。本共识包括重症患者凝血功能障碍的有关概念、评估方法及诊断标准3个部分,共12条推荐意见,以期为临床工作提供相应指导。