大鼠脑缺血/再灌注过程中血流量和脑组织含水量的变化趋势*

目的:研究大鼠脑缺血/再灌注过程中血流量及与脑组织水含量变化的趋势。方法:选取5只成年SD雄性大鼠(n=5),参照改良Zea-Longa线栓法制备大鼠大脑中动脉缺血/再灌注模型,2 h后拔出线栓。利用PeriCam PSI血流灌注成像系统实时监测大鼠在缺血前及缺血5 min、30 min、1 h、2 h、再灌注5 min、30 min、1 h、2 h、4 h、6 h及24 h的血流灌注量,记录在ROI(感兴趣区)测量的数值。再选取15只成年SD雄性大鼠,分为Control组、缺血2 h、再灌注30 min、4 h及24 h组(n=3)。正常组不做任何处理,实验组按上述线栓法制备MCAO模型。取新鲜脑组织用干湿重法测定其左、右半球的水含量。结果:栓塞时缺血侧血流量逐渐下降,缺血2 h下降最低(P＜0.05);再灌注早期血流量恢复较大(P＜0.05),30 min时显著下降(P＜0.05),4 h明显上升(P＜0.05),24 h再次上升(P＜0.05)但低于缺血前血流量(P＞0.05)。脑组织水含量测量,缺血2 h组和再灌注30 min组与正常组无明显差异(P＞0.05);再灌4 h组和再灌24 h组明显增高(P＜0.05),且再灌24 h组明显高于再灌4 h组(P＜0.05)。结论:大鼠脑缺血/再灌注过程中血流量和脑组织中水含量的变化存在一定的规律,且脑组织中水含量与再灌注过程中血流量的变化有一定关系。     

急性脑梗死并发肺部感染患者预后及危险因素分析

目的分析急性脑梗死并发肺部感染患者病原菌分布、病原菌耐药性、患者用药特征及其危险因素。方法选取2015年3月至2017年3月在我院急诊科进行住院治疗,且年龄60岁的急性脑梗死并发肺部感染患者60例为研究对象,对患者的一般资料及病原菌分布情况、耐药情况和患者用药情况进行分析。结果 60例患者中有30例出现肺部感染,感染率为50.00%。肺部感染患者中死亡4例。肺部感染患者痰液中共培养出28株病原菌,其中革兰阴性菌21株,革兰阳性菌5株,真菌2株。30例肺部感染患者共使用6种抗感染药物,其中哌拉西林/舒巴坦的使用频率最高,其次为依替米星及美罗培南。Logistic回归分析显示,病原菌分布、耐药情况和患者用药情况与患者的预后存在相关性。结论急性脑梗死并发肺部感染患者的病原菌分布、耐药情况及患者用药情况与患者的预后密切相关,应针对上述因素给予患者合理的治疗。     

The thermodynamics of thinking: connections between neural activity,energy metabolism and blood flow

Several current functional neuroimaging methods are sensitive to cerebral metabolism and cerebral blood flow (CBF) rather than the underlying neural activity itself. Empirically, the connections between metabolism, flow and neural activity are complex and somewhat counterintuitive: CBF and glycolysis increase more than seems to be needed to provide oxygen and pyruvate for oxidative metabolism, and the oxygen extraction fraction is relatively low in the brain and decreases when oxygen metabolism increases. This work lays a foundation for the idea that this unexpected pattern of physiological changes is consistent with basic thermodynamic considerations related to metabolism. In the context of this thermodynamic framework, the apparent mismatches in metabolic rates and CBF are related to preserving the entropy change of oxidative metabolism, specifically the O₂/CO₂ ratio in the mitochondria. However, the mechanism supporting this CBF response is likely not owing to feedback from a hypothetical O₂ sensor in tissue, but rather is consistent with feed-forward control by signals from both excitatory and inhibitory neural activity. Quantitative predictions of the thermodynamic framework, based on models of O₂ and CO₂ transport and possible neural drivers of CBF control, are in good agreement with a wide range of experimental data, including responses to neural activation, hypercapnia, hypoxia and high-altitude acclimatization.This article is part of the theme issue ‘Key relationships between non-invasive functional neuroimaging and the underlying neuronal activity’.     

醒脑静联合纳洛酮对急性脑出血伴意识障碍患者神经功能、炎性因子和氧化应激的影响

摘要 目的：探讨纳洛酮联合醒脑静对急性脑出血（ACH）伴意识障碍患者炎性因子、神经功能和氧化应激的影响。方法：选取2017年2月~2019年12月期间我院收治的95例ACH伴意识障碍患者,按照随机数字表法将上述患者分为对照组（n=47）和研究组（n=48）,对照组患者予以纳洛酮治疗,研究组则在对照组的基础上联合醒脑静治疗,比较两组患者疗效、神经功能、炎性因子和氧化应激指标,记录两组不良反应发生情况。结果：研究组治疗10 d后的临床总有效率为91.67%（44/48）,高于对照组的74.47%（35/47）（P<0.05）。两组治疗10 d后美国国立卫生研究院卒中量表（NIHSS）评分,白介素-6（IL-6）、C反应蛋白（CRP）以及肿瘤坏死因子-α（TNF-α）、丙二醛（MDA）水平均较治疗前下降,且研究组低于对照组（P<0.05）。两组治疗10 d后超氧歧化酶 (SOD)水平均较治疗前升高,且研究组高于对照组（P<0.05）。两组不良反应发生率对比未见统计学差异（P>0.05）。结论：醒脑静联合纳洛酮治疗ACH伴意识障碍患者,疗效显著,可有效改善患者神经功能、炎性因子和氧化应激,且安全性较好。     

入院时血清钙水平与高血压性脑出血血肿体积、神经功能及预后的关系研究

摘要 目的：探讨入院时血清钙水平与高血压性脑出血血肿体积、神经功能及预后的关系。方法：选择2018年9月-2020年4月我院收治的高血压性脑出血患者102例,根据患者入院时血清钙水平将其分为低血钙组（血清钙<2.1 mmol/L, n=34）、正常血钙组（2.1 mol/L≤血清钙≤2.7 mmol/L, n=39）和高血钙组（血清钙>2.7 mmol/L, n=29）,比较各组性别、血肿体积、入院美国国立卫生研究院卒中量表（NIHSS）评分等临床资料。所有患者随访1年,观察患者格拉斯哥预后量表（GOS）评分,根据患者预后情况将患者分为预后良好组（n=84）和预后不良组（n=18）,比较两组血清钙、血肿体积、入院NIHSS评分、GOS评分。应用受试者工作特征（ROC）曲线分析血清钙水平对患者预后的预测价值。结果：三组血肿体积、入院NIHSS评分、GOS评分、1年病死率、1年再出血率、总预后不良率比较有统计学差异（P<0.05）。预后不良组血清钙水平、GOS评分显著低于预后良好组,血肿体积、入院NIHSS评分显著高于预后良好组（P<0.05）。Pearson相关性分析显示：高血压性脑出血患者入院时血清钙水平与脑出血血肿体积、入院NIHSS评分呈负相关,与GOS评分呈正相关（P＜0.05）。ROC曲线分析显示入院时血清钙预测高血压脑出血不良预后的曲线下面积为0.129（95%CI：0.073~0.179）。结论：高血压性脑出血患者入院时血清钙水平与血肿体积、神经功能及预后存在一定关联,且入院时血清钙对高血压性脑出血不良预后具有一定预测价值。     

α-Synuclein在脑缺血中的作用

α-Syn(α-Synuclein,SNAC)最初是从阿尔茨海默病患者大脑的淀粉样斑块中分离出来的一种蛋白质,在突触活动中扮演着重要的角色。α-Syn主要在脑中表达,研究发现其参与脑缺血损伤发生发展。在现有证据的基础上,该文简要介绍α-Syn的基本概念,并介绍α-Syn在脑缺血后的表达变化,重点探讨α-Syn在脑缺血中的作用。该文提供的信息可能有助于对α-Syn进行深入探索,α-Syn可能是未来脑缺血诊治的有效靶点。     

A gait index may underestimate changes of gait: a comparison of the Movement Deviation Profile and the Gait Deviation Index

The ability of the Movement Deviation Profile (MDP) and Gait Deviation Index (GDI) to detect gait changes was compared in a child with cerebral palsy who underwent game training. Conventional gait analysis showed that sagittal plane angles became mirrored about normality after training. Despite considerable gait changes, the GDI showed minimal change, while the MDP detected a difference equal to a shift between 10-9 on the Functional Assessment Questionnaire scale. Responses of the GDI and MDP were examined during a synthetic transition of the patient's curves from before intervention to a state mirrored about normality. The GDI showed a symmetric response on the two opposite sides of normality but the neural network based MDP gave an asymmetric response reflecting faithfully the unequal biomechanical consequences of joint angle changes. In conclusion, the MDP can detect altered gait even if the changes are missed by the GDI.     

Computational haemodynamics in two idealised cerebral wide-necked aneurysms after stent placement

Endovascular stents are being commonly used to treat cerebral wide-necked aneurysms recently. The effect of a stent placed in the parent artery is not only to protect the parent artery from occlusion, due to extension of coils and thrombosis, but also to act as flow diverter to vary the haemodynamics in the aneurysm. In this article, two idealised cerebral wide-necked aneurysms were created, one was sidewall aneurysm with curved parent vessel and the other was terminal aneurysm with the bifurcated parent vessel. The plexiglass models of the two aneurysms were ‘treated’ with commercial porous intravascular stents. The stented physical models were scanned by Micro-CT and the numerical models of the two idealised cerebral wide-necked aneurysms after stent placement were constructed from the scanned image files. The pulsatile flow of non-Newtonian fluid inside the models was simulated by using computational fluid dynamics package. From the simulated flow dynamics, various haemodynamic characteristics such as velocity contours, wall shear stress and oscillatory shear index (OSI) were computed. The velocity of the jet entering the sacs reduced after stent was deployed across the necks of both sidewall and terminal aneurysms; the wall shear stress on the distal neck of sidewall aneurysm reduced, the wall shear stress on the dome of the terminal aneurysm increased and the OSI on the dome of the terminal aneurysm reduced. Therefore, stent placement not only promotes thrombus formation in both aneurysm models but also reduces the regrowth risk of the sidewall aneurysm and the rupture risk of the terminal aneurysm.     

Formation of Free Radicals and Nitric Oxide Derivative of Hemoglobin in Rats During Shock Syndrome

Free radicals have been postulated to play an important role as mediators in the pathogenesis of shock syndrome and multiple-organ failure. We attempted to directly detect the increased formation of radicals by Electron Spin Resonance (ESR) in animal models of shock, namely the endotoxin (ETX) shock or the hemorrhagic shock of the rat. In freeze-clamped lung tissue, a small but significant increase of a free radical signal was detected after ETX application. In the blood of rats under ETX shock, a significant ESR signal with a triplet hyperfine structure was observed. The latter ESR signal evolved within several hours after the application of ETX and was localized in the red blood cells. This signal was assigned to a nitric oxide (NO) adduct of hemoglobin with the tentative structur ((a2+ NO)/23+)2. The amount of hemoglobin-NO formed, up to 0.8% of total hemoglobin, indicated that under ETX shock a considerable amount of NO was produced in the vascular system. This NO production was strongly inhibited by the arginine analog N^G-monomethyl-arginine (NMMA). The ESR signal of Hb-NO was also observed after severe hemorrhagic shock. There are three questions, namely (i) the type of vascular cells and the regulation of the process forming such a large amount of NO during ETX shock, (ii) the pathophysiological implications of the formed NO, effects which have been described as cytotoxic mediator, endothelium-derived relaxing factor (EDRF) or inhibitor of platelet aggregation, and (iii) the possible use of Hb-NO for monitoring phases of shock syndrome.     

Growth hormone and outcome in patients with intracerebral hemorrhage: a pilot study

Background: Endocrine alterations of the hypothalamic-pituitary-axis are one of the first measurable physiological changes in cerebral insults. During acute stress, human growth hormone (GH) is stimulated and has shown to have a prognostic value in various diseases. Within this pilot study, we evaluated the prognostic value of GH in patients with acute intracerebral hemorrhage (ICH).

Methods: In a prospective observational study in 40 consecutive patients with ICH, GH was measured on admission. The prognostic value of GH to predict 30-day mortality and 90-day functional outcome was assessed. Favorable functional outcome was defined as Barthel Index score >85 points and Modified Rankin Scale <3 points.

Results: GH levels were increased in patients who died within 30 days as compared to survivors (0.45 (IQR 0.20–1.51) vs. 1.51 (IQR 0.91–4.08) p?=?0.03), and in patients with an unfavorable functional outcome as compared to patients with a favorable functional outcome after 90 days 0.28 (IQR 0.16–0.61) vs. 0.78 (IQR 0.31–1.99) p?=?0.03). For mortality prediction, receiver-operating-characteristics revealed an area under the curve (AUC) on admission for GH of 0.78 (95% CI 0.60–0.96), which was in the range of the Glasgow Coma Score (GCS) (AUC 0.82 (95% CI 0.59–1.00) p?=?0.80). For functional outcome prediction, GH had an AUC of 0.71 (95% CI 0.54–0.87), which was statistically not different from the GCS (AUC 0.81 (95% CI 0.68–0.94) p?=?0.36).

Conclusions: In our small cohort of patients with acute ICH, elevated GH level were associated with increased mortality and worse outcome. If confirmed in a larger study, GH levels may be used as an additional prognostic factor in ICH patients. (ClincalTrials.gov number NCT00390962).