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1.

Purpose

The aim of this study was to assess the effect of acute bilateral jugular vein compression on: (1) pial artery pulsation (cc-TQ); (2) cerebral blood flow velocity (CBFV); (3) peripheral blood pressure; and (4) possible relations between mentioned parameters.

Methods

Experiments were performed on a group of 32 healthy 19–30 years old male subjects. cc-TQ and the subarachnoid width (sas-TQ) were measured using near-infrared transillumination/backscattering sounding (NIR-T/BSS), CBFV in the left anterior cerebral artery using transcranial Doppler, blood pressure was measured using Finapres, while end-tidal CO2 was measured using medical gas analyser. Bilateral jugular vein compression was achieved with the use of a sphygmomanometer held on the neck of the participant and pumped at the pressure of 40 mmHg, and was performed in the bend-over (BOPT) and swayed to the back (initial) position.

Results

In the first group (n = 10) during BOPT, sas-TQ and pulse pressure (PP) decreased (−17.6% and −17.9%, respectively) and CBFV increased (+35.0%), while cc-TQ did not change (+1.91%). In the second group, in the initial position (n = 22) cc-TQ and CBFV increased (106.6% and 20.1%, respectively), while sas-TQ and PP decreases were not statistically significant (−15.5% and −9.0%, respectively). End-tidal CO2 remained stable during BOPT and venous compression in both groups. Significant interdependence between changes in cc-TQ and PP after bilateral jugular vein compression in the initial position was found (r = −0.74).

Conclusions

Acute bilateral jugular venous insufficiency leads to hyperkinetic cerebral circulation characterised by augmented pial artery pulsation and CBFV and direct transmission of PP into the brain microcirculation. The Windkessel effect with impaired jugular outflow and more likely increased intracranial pressure is described. This study clarifies the potential mechanism linking jugular outflow insufficiency with arterial small vessel cerebral disease.  相似文献   

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目的:探讨胚胎型大脑后动脉(Fetal origin of the posterior cerebral artery,FTP)与脑白质病之间的关系。方法:收集2013年1月~2014年6月在我院住院患者共485例,所有患者均行头颅磁共振平扫及血管成像,观察脑白质病变、急性脑梗死及FTP存在与否,并分为观察组(脑白质病组)和对照组(无脑白质病组),比较FTP的发生率。结果:观察组和对照组分别为232例和253例,观察组共发现53例FTP患者(左侧、右侧、双侧FTP分别为15例、19例、19例),FTP总发生率为22.8%,左侧、右侧、双侧FTP发生率分别为6.5%、8.2%、8.2%;对照组98例FTP患者(左侧、右侧、双侧FTP分别为26例、44例、28例),FTP总发生率为38.7%,左侧、右侧、双侧FTP发生率分别为10.3%、17.4%、11.1%,观察组FTP总发生率及右侧FTP发生率明显低于对照组(P0.001和P0.01)。232例观察组中急性脑梗死患者共156例,无急性脑梗死患者76例,其中急性脑梗死组有28例FTP患者(左侧、右侧、双侧FTP分别为7例、15例、6例),FTP总发生率及左侧、右侧、双侧FTP发生率分别为17.9%、4.5%、9.6%、3.8%;而无急性脑梗死的患者中,有24例FTP患者(左侧、右侧、双侧FTP分别为8例、4例、12例),FTP总发生率及左侧、右侧、双侧FTP发生率分别为31.6%、10.5%、5.3%、15.8%,观察组FTP总发生率及双侧FTP发生率明显低于对照组(P0.05和P0.01)。结论:FTP的存在可能一定程度上降低脑白质病甚至脑梗死的发生。  相似文献   

4.
To determine the optimal velocity values in diagnosing unilateral middle cerebral artery (MCA) stenosis by Transcranial Doppler (TCD), and improve the diagnostic accuracy using magnetic resonance angiography (MRA), a total of 302 unilateral MCA stenosis patients undergoing TCD also consented to a MRA of the intracranial arteries. The peak systolic velocity (PSV) and each MCA spectrum for each patient were recorded. Using the MRA to confirm, the degree of middle cerebral artery stenosis was categorized into four groups: normal (normal caliber and signal), mild (<50 %), moderate (50–69 %), severe (70–99 %, or no flow detected). The velocity difference among these four groups was significant (P < 0.001). The optimal PSV values for normal and stenosis were 160 cm/s. For mild and moderate were 200 cm/s, for moderate and severe were 280 cm/s. Using PSV as the diagnostic criteria, the Kappa number was >0.668. The optimal PSV differential value for mild and moderate was 70 cm/s, for moderate and severe at 120 cm/s. Optimal combined criteria for moderate stenosis were PSV >200 cm/s and PSV differential value >70 cm/s (specificity 87.2 %), for severe stenosis were PSV >280 cm/s and PSV differential value >120 cm/s (sensibility 81.6 %). Transcranial Doppler distinguishes normal and MCA stenosis with a reduced lumen diameter of less than 50 %. Using the PSV criteria, TCD has a high coincidence rate with MRA in the diagnosis of MCA stenosis. Combined PSV differential value and the abnormal spectrum may improve the accuracy of TCD in diagnosing moderate or severe stenosis.  相似文献   

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Background

The middle cerebral artery supplies long end-artery branches to perfuse the deep white matter and shorter peripheral branches to perfuse cortical and subcortical tissues. A generalized vasodilatory stimulus such as carbon dioxide not only results in an increase in flow to these various tissue beds but also redistribution among them. We employed a fast step increase in carbon dioxide to detect the dynamics of the cerebral blood flow response.

Methodology/Principal Findings

The study was approved by the Research Ethics Board of the University Health Network at the University of Toronto. We used transcranial ultrasound to measure the time course of middle cerebral artery blood flow velocity in 28 healthy adults. Normoxic, isoxic step increases in arterial carbon dioxide tension of 10 mmHg from both hypocapnic and normocapnic baselines were produced using a new prospective targeting system that enabled a more rapid step change than has been previously achievable. In most of the 28 subjects the responses at both carbon dioxide ranges were characterised by more complex responses than a single exponential rise. Most responses were characterised by a fast initial response which then declined rapidly to a nadir, followed by a slower secondary response, with some showing oscillations before stabilising.

Conclusions/Significance

A rapid step increase in carbon dioxide tension is capable of inducing instability in the cerebral blood flow control system. These dynamic aspects of the cerebral blood flow responses to rapid changes in carbon dioxide must be taken into account when using transcranial blood flow velocity in a single artery segment to measure cerebrovascular reactivity.  相似文献   

8.
To investigate the association of single nucleotide polymorphism in the matrix metalloproteinase-3 (MMP3) gene promoter with the susceptibility to the middle cerebral artery stenosis. A case–control study was performed by determining the genotype of MMP3 gene promoter region using polymerase chain reaction-restriction fragment length polymorphism in 119 patients with middle cerebral artery stenosis documented by transcranial Doppler compared to 92 control patients. The frequencies of 5A and 6A alleles in MMP3 promoter region were 16.0 and 84.0% respectively in case group compared to 15.8 and 84.2% in control group with no significant difference between the two groups (P > 0.05). No significant difference was also observed in the distribution of genotypes 5A/5A,5A/6A, and 6A/6A between middle cerebral artery stenosis and control groups. Compared to 5A/5A + 5A/6A genotypes,the 6A/6A genotype did not significantly modify the risk of developing the middle cerebral artery stenosis. The MMP3–1171 dupA promoter polymorphisms are not valuable markers of susceptibility of the middle cerebral artery stenosis in this sample of population studied.  相似文献   

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目的:探讨饮酒、吸烟与冠状动脉病变程度的相关性。方法:抽取行冠脉造影的男性患者(343例),排除患有高血压病、糖尿病、肝肾功能等异常的患者,根据患者是否吸烟、饮酒将其分为四组,吸烟+饮酒组(86例),吸烟+非饮酒组(135例),饮酒+非吸烟饮酒组(16例),非吸烟+非饮酒组(106例)。通过Gensini积分系统评价和比较各组冠脉病变的情况,分析评估冠心病的风险因素以及饮酒、吸烟与冠心病的关系。结果:吸烟+非饮酒组Gensini评分最高(33.89±31.14)分别与另外三组有统计学意义(P0.05)。饮酒+非吸烟组最低(9.31±10.88),分别与另外三组有统计学意义(P0.05)。单因素分析结果显示年龄、饮酒、TG、HDL-C是发生冠心病的危险因素,logistic回归分析结果显示饮酒是发生冠心病的保护因素,年龄与TG是发生冠心病的危险因素。结论:吸烟为冠状动脉病变高危因素,饮酒是发生冠心病的保护因素。  相似文献   

10.
目的:探讨胎儿大脑中动脉(Middle cerebral artery,MCA)与脐动脉(umbilical artery,UmA)和孕妇子宫动脉(uterine artery,UtA)测量诊断胎儿宫内窘迫的临床价值。方法:将我院自2017年1月至2019年1月间收治的孕晚期发生胎儿宫内窘迫的孕妇80例作为研究组,选择同期入院各项指标正常的健康孕妇78例作为对照组,对比观察两组胎儿MCA与UmA和孕妇UtA预测胎儿窘迫的价值及胎儿MCA与UmA与新生儿Apgar评分的相关性。结果:研究组孕妇UtA血流参数脐血流搏动指数(pulsatility index,PI)、脐血流阻力指数(resistance index,RI)和收缩/舒张比(systole/diastole ratios,S/D)指标水平均明显高于对照组,研究组胎儿MCA血流参数PI、S/D均明显低于对照组,研究组患儿UmA的血流参数PI和S/D高于对照组(P<0.05),RI比较差异无统计学意义(P>0.05);研究组新生儿Apgar评分≤7分的比例为40.00%,明显高于对照组15.38%。研究组UmA-PI、UmA-RI和UmA-S/D随着Apgar评分的降低呈现升高的趋势,MCA-PI、MCA-S/D和MCA-S/D随着Apgar评分的降低呈现逐渐减低的趋势。UtA血流参数联合MCA血流参数诊断胎儿宫内窘迫的敏感度为97.50%,特异性为96.25%,均明显高于各项参数单独诊断在的敏感度和特异性(P<0.05)。结论:临床可利用孕晚期孕妇UtA、胎儿UmA和MCA的血流动力学参数改变来预测胎儿宫内窘迫发生的几率,根据胎儿UmA和MCA的血流指标随着Apgar评分的变化趋势,可指导临床早期干预,降低胎儿出生缺陷和死亡率,临床价值较高,可推广使用。  相似文献   

11.

Background and Purpose

Longitudinal functional imaging studies of stroke are key in identifying the disease progression and possible therapeutic interventions. Here we investigate the applicability of real-time functional optoacoustic imaging for monitoring of stroke progression in the whole brain of living animals.

Materials and Methods

The middle cerebral artery occlusion (MCAO) was used to model stroke in mice, which were imaged preoperatively and the occlusion was kept in place for 60 minutes, after which optoacoustic scans were taken at several time points.

Results

Post ischemia an asymmetry of deoxygenated hemoglobin in the brain was observed as a region of hypoxia in the hemisphere affected by the ischemic event. Furthermore, we were able to visualize the penumbra in-vivo as a localized hemodynamically-compromised area adjacent to the region of stroke-induced perfusion deficit.

Conclusion

The intrinsic sensitivity of the new imaging approach to functional blood parameters, in combination with real time operation and high spatial resolution in deep living tissues, may see it become a valuable and unique tool in the development and monitoring of treatments aimed at suspending the spread of an infarct area.  相似文献   

12.
We evaluated the optimal flow velocity of transcranial doppler (TCD) in detecting unilateral middle cerebral artery (MCA) stenosis and stenosis grading by magnetic resonance angiography (MRA) as the reference standard. 302 nonconsecutive patients with unilateral MCA stenosis detected by TCD underwent MRA of the intracranial arteries. The peak systolic velocity (PSV), mean flow velocity (MFV), and end-diastolic velocity (EDV) of each MCA were recorded. 604 MCA were categorized into four groups depending on the stenosis severity: normal MCA (n = 319, 52.8 %), mild stenosis (n = 94, 15.6 %), moderate stenosis (n = 66, 10.9 %), and severe stenosis (n = 125, 20.7 %). Significant differences in PSV, MFV, and EDV between these four groups were observed (P < 0.001, respectively). The optimal cutoff velocities for detecting MCA stenosis were: PSV = 160 cm/s, MFV = 100 cm/s, EDV = 60 cm/s; the optimal cutoff points to distinguish mild from moderate stenosis were: PSV = 200 cm/s, MFV = 120 cm/s, EDV = 80 cm/s; the cutoffs to distinguish moderate from severe stenosis were: PSV = 280 cm/s, MFV = 180 cm/s, EDV = 110 cm/s. Using PSV as the diagnostic criteria, the correlation for diagnosing MCA stenosis using TCD and MCA was good (Kappa number κ = 0.668); using as MFV criteria, κ = 0.641. The optimal cutoff PSV values in stenosis grading on TCD were 160, 200, and 280 cm/s. The optimal cutoff MFV values were 100, 120, and 180 cm/s. PSV is more accurate than MFV in detecting and grading MCA stenosis.  相似文献   

13.

Background

The incidence of several adverse pregnancy outcomes including fetal growth restriction are higher in pregnancies where the fetus is male, leading to suggestions that placental insufficiency is more common in these fetuses. Placental insufficiency associated with fetal growth restriction may be identified by multi-vessel Doppler assessment, but little evidence exists regarding sex specific differences in these Doppler indices or placental function. This study aims to investigate sex specific differences in fetal and placental perfusion and to correlate these changes with intra-partum outcome.

Methods and Findings

This is a prospective cohort study. We measured Doppler indices of 388 term pregnancies immediately prior to the onset of active labour (≤3 cm dilatation). Fetal sex was unknown at the time of the ultrasound assessment. Information from the ultrasound scan was not made available to clinical staff. Case notes and electronic records were reviewed following delivery. We report significantly lower Middle Cerebral artery pulsatility index (1.34 vs. 1.43, p = 0.004), Middle Cerebral artery peak velocity (53.47 cm/s vs. 58.10 cm/s, p = <0.001), and Umbilical venous flow/kg (56 ml/min/kg vs. 61 ml/min/kg, p = 0.02) in male fetuses. These differences however, were not associated with significant differences in intra-partum outcome.

Conclusion

Sex specific differences in feto-placental perfusion indices exist. Whilst the physiological relevance of these is currently unknown, the identification of these differences adds to our knowledge of the physiology of male and female fetuses in utero. A number of disease processes have now been shown to have an association with changes in fetal haemodynamics in-utero, as well as having a sex bias, making further investigation of the sex specific differences present during fetal life important. Whilst the clinical application of these findings is currently limited, the results from this study do provide further insight into the gender specific circulatory differences present in the fetal period.  相似文献   

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目的:探讨急性心肌梗死(AMI)患者冠状动脉病变严重程度与脉压和脉压指数的关系.方法:对185例AMI患者进行冠状动脉造影术,冠状动脉病变严重程度用冠状动脉病变支数和Gensini积分来表示,并测定收缩压(SBP)和舒张压(DBP)并计算脉压(PP)及脉压指数(PPI).结果:与脉压<65mmHg的患者相比,脉压≥65mmHg的患者冠状动脉3支血管病变的患病率和Gensini积分显著增高(P<0.01).与PPI<0.500的患者相比,PPI≥0.500的患者冠状动脉3支血管病变的患病率和Gensini积分亦显著增高(P<0.01).结论:PP和PPI与AMI患者冠状动脉病变程度密切相关,在临床上具有指导作用.  相似文献   

15.
正常与脑缺血大鼠的脑皮质蛋白质差异分析鉴定   总被引:10,自引:0,他引:10  
Wistar大鼠随机分为正常组和模型组,采用改进的线栓法制备模型,在规定的时间点快速断头取脑,分离脑皮质组织,提取蛋白质后双向电泳展示,以ImageMaster 2D Elite v301软件对2_DE图谱进行差异表达分析,目标蛋白点用基质辅助激光解析电离质谱测定肽质量指纹图进行鉴定。线粒体应激70蛋白前体、血小板活化因子乙酰基水解酶Ibβ亚单位、ADP核糖基化因子蛋白3、电压依赖性阴离子选择通道蛋白1、泛素C末端水解酶同工酶L1、突触结合蛋白等11个蛋白在模型6h组表达上调,谷胱甘肽S-转移酶omega 1、 谷胱甘肽S-转移酶P、Cu-Zn超氧化物歧化酶、 ATP合酶D链、G蛋白β亚单位1、微管蛋白β链15、苹果酸脱氢酶等15个蛋白在模型6h组表达上调。胆绿素还原酶B、细胞因子A4前体为模型组新出现点,腺苷酸激酶同工酶1在模型组消失,Thiore doxin peroxidase 1在模型组分为2个点。以双向电泳技术得到分辨率较好的电泳图谱,并初步鉴定脑缺血后差异表达蛋白,为深入研究缺血性脑损伤病理机制奠定了基础。  相似文献   

16.
Stroke is the third most common cause of death and a main cause of acquired adult disability in developed countries. Only very limited therapeutical options are available for a small proportion of stroke patients in the acute phase. Current research is intensively searching for novel therapeutic strategies and is increasingly focusing on the sub-acute and chronic phase after stroke because more patients might be eligible for therapeutic interventions in a prolonged time window. These delayed mechanisms include important pathophysiological pathways such as post-stroke inflammation, angiogenesis, neuronal plasticity and regeneration. In order to analyze these mechanisms and to subsequently evaluate novel drug targets, experimental stroke models with clinical relevance, low mortality and high reproducibility are sought after. Moreover, mice are the smallest mammals in which a focal stroke lesion can be induced and for which a broad spectrum of transgenic models are available. Therefore, we describe here the mouse model of transcranial, permanent coagulation of the middle cerebral artery via electrocoagulation distal of the lenticulostriatal arteries, the so-called “coagulation model”. The resulting infarct in this model is located mainly in the cortex; the relative infarct volume in relation to brain size corresponds to the majority of human strokes. Moreover, the model fulfills the above-mentioned criteria of reproducibility and low mortality. In this video we demonstrate the surgical methods of stroke induction in the “coagulation model” and report histological and functional analysis tools.  相似文献   

17.
目的:探讨低频超声治疗动脉粥样硬化性大脑中动脉(MCA)狭窄急性脑梗死(ACI)患者的临床疗效及对炎症指标的影响。方法:选取2015年10月至2018年5月华中科技大学同济医学院附属荆州医院收治的动脉粥样硬化性MCA狭窄ACI患者82例,按随机数字表法分为对照组和观察组,每组各41例。对照组行常规治疗,观察组在对照组的基础上行低频超声治疗,对所有患者治疗前及治疗14 d后的神经功能进行评分,低频超声检测MCA狭窄段峰值血流速度(Vs)、微栓子信号(MES)阳性率,比较治疗前、治疗7 d后、14 d后两组患者血清高敏C-反应蛋白(hs-CRP)水平。结果:治疗14 d后两组的美国国立卫生研究院卒中量表(NIHSS)评分下降,且观察组较对照组NIHSS评分更低(P0.05);治疗14 d后观察组MCA狭窄段Vs低于治疗前(P0.05),而对照组与治疗前比较无统计学差异(P0.05)。治疗7 d后、14 d后观察组MES阳性率均低于对照组(P0.05)。两组治疗7 d后、14 d后hs-CRP水平低于治疗前,且治疗14 d后低于治疗7 d后(P0.05);而观察组治疗7 d后、14 d后hs-CRP水平低于对照组(P0.05)。结论:低频超声治疗动脉粥样硬化性MCA狭窄ACI患者疗效显著,可改善神经功能与炎症反应,减缓Vs,提高动脉粥样硬化斑块的稳定性。  相似文献   

18.
The translational potential of pre-clinical stroke research depends on the accuracy of experimental modeling. Cerebral perfusion monitoring in animal models of acute ischemic stroke allows to confirm successful arterial occlusion and exclude subarachnoid hemorrhage. Cerebral perfusion monitoring can also be used to study intracranial collateral circulation, which is emerging as a powerful determinant of stroke outcome and a possible therapeutic target. Despite a recognized role of Laser Doppler perfusion monitoring as part of the current guidelines for experimental cerebral ischemia, a number of technical difficulties exist that limit its widespread use. One of the major issues is obtaining a secure and prolonged attachment of a deep-penetration Laser Doppler probe to the animal skull. In this video, we show our optimized system for cerebral perfusion monitoring during transient middle cerebral artery occlusion by intraluminal filament in the rat. We developed in-house a simple method to obtain a custom made holder for twin-fibre (deep-penetration) Laser Doppler probes, which allow multi-site monitoring if needed. A continuous and prolonged monitoring of cerebral perfusion could easily be obtained over the intact skull.  相似文献   

19.
Apoptosis and neural degeneration are characteristics of cerebral ischemia and brain damage. Diabetes is associated with worsening of brain damage following ischemic events. In this study, the authors characterize the influence of focal cerebral ischemia, induced by middle cerebral artery occlusion, on 2 indexes of apoptosis,TUNEL(terminal deoxynucleotidyl transferase–mediated deoxyuridine 5-triphosphate nick end-labeling) staining and caspase- 3 immunohistochemistry. Diabetes was induced in normal rats using streptozotocin and maintained for 5 to 6 weeks. The middle cerebral artery of both normal and diabetic rats was occluded and maintained from 24 or 48 hours. Sham-operated normal and diabetic animals served as controls. Following 24 to 48 hours of occlusion, the animals were sacrificed and the brains were removed, sectioned, and processed for TUNEL staining or caspase-3 immunohistochemistry. Middle cerebral artery occlusion in normal rats was associated with an increase in the number of both TUNEL-positive and caspase-3– positive cells in selected brain regions (hypothalamic preoptic area, piriform cortex, and parietal cortex) when compared to nonoccluded controls. Diabetic rats without occlusion showed significant increases in both TUNEL-positive and caspase-3–positive cells compared to normal controls. Middle cerebral artery occlusion in diabetic rats resulted in increases in TUNEL-positive as well as caspase-3–positive cells in selected regions, above those seen in nonoccluded diabetic rats. Both TUNEL staining and caspase-3 immunohistochemistry revealed that the number of apoptotic cells in diabetic animals tended to be greatest in the preoptic area and parietal cortex. The authors conclude that focal cerebral ischemia is associated with a significant increase in apoptosis in nondiabetic rats, and that diabetes alone or diabetes plus focal ischemia are associated with significant increases in apoptotic cells.  相似文献   

20.

Background

The presence of stenoses that significantly impair blood flow and cause myocardial ischemia negatively affects prognosis of patients with stable coronary artery disease. Altered platelet reactivity has been associated with impaired prognosis of stable coronary artery disease. Platelets are activated and form complexes with leukocytes in response to microshear gradients caused by friction forces on the arterial wall or flow separation. We hypothesized that the presence of significantly flow-limiting stenoses is associated with altered platelet reactivity and formation of platelet-leukocyte complexes.

Methods

One hundred patients with stable angina were studied. Hemodynamic significance of all coronary stenoses was assessed with Fractional Flow Reserve (FFR). Patients were classified FFR-positive (at least one lesion with FFR≤0.75) or FFR-negative (all lesions FFR>0.80). Whole blood samples were stimulated with increasing concentrations of ADP, TRAP, CRP and Iloprost with substimulatory ADP. Expression of P-selectin as platelet activation marker and platelet–leukocyte complexes were measured by flowcytometry. Patients were stratified on clopidogrel use. FFR positive and negative patient groups were compared on platelet reactivity and platelet-leukocyte complexes.

Results

Platelet reactivity between FFR-positive patients and FFR-negative patients did not differ. A significantly lower percentage of circulating platelet-neutrophil complexes in FFR-positive patients and a similar non-significant decrease in percentage of circulating platelet-monocyte complexes in FFR-positive patients was observed.

Conclusion

The presence of hemodynamically significant coronary stenoses does not alter platelet reactivity but is associated with reduced platelet-neutrophil complexes in peripheral blood of patients with stable coronary artery disease.  相似文献   

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