急性无氧功率自行车运动对颈总动脉弹性模量 和局部血液动力学的影响

目的研究急性无氧功率自行车运动对不同性别人体颈总动脉弹性模量和局部血液动力学的影响。方法以9名男性和8名女性20～30岁年龄段的健康志愿者作为研究对象,使用无氧功率自行车持续进行4组相同强度的急性运动训练。应用彩色超声多普勒分别检测静息状态及每组运动训练后的颈总动脉管径波形、轴心流速波形,用电子自动血压计同步检测心率和血压大小。运用经典血液动力学理论对检测数据进行分析,计算颈总动脉的弹性模量和局部血液动力学参数,包括压力-应变弹性模量、流量率、周向应变、壁面切应力和振荡剪切指数。结果运动后心率增加;随着运动的积累,颈总动脉弹性模量呈增加趋势;一个心动周期内轴心血流速度和流量率最大值与平均值上升,流速和流量率最小值下降;收缩压和平均压增高,舒张压无明显改变;周向应变无明显改变;切应力最大值有明显增加的趋势,切应力最小值下降趋势明显;振荡剪切指数也有增大的趋势。结论急性无氧功率自行车运动可增加20～30岁年龄段不同性别志愿者的颈总动脉弹性模量,并对颈总动脉局部血液运动学和动力学功能参数产生明显的影响。本文结果将为无氧运动调控脑血管功能提供有用的血液动力学信息。     

喉罩对颈总动脉和颈内动脉血流动力学的影响

目的 研究喉罩对颈总动脉(CCA)和颈内动脉(ICA)内径、血流速率和血流量等血流动力学参数的影响.方法 随机选择择期全麻下行腹腔镜胆囊切除术患者60例,为美国麻醉医师协会(ASA)Ⅰ～Ⅲ级.根据不同年龄分为中青年组(A组,20～59岁)和老年组(B组,60～85岁).按不同的喉罩套囊内压力将A组和B组分为4个亚组,即A1、B1(套囊内压为20～30 cm H2O)(1 cm H2O=0.098 kPa)和A2、B2(套囊内压为40～50 cm H2O),每组15例.所有患者术毕后送入ICU复苏,尚未清醒时拔除气管导管,而后置入喉罩.记录置入喉罩前(T0),置入喉罩后3 min(T1)、10 min(T2)和拔除喉罩后(T3)各时点CCA和ICA的内径、血流速率和血流量等血流动力学参数以及生命体征参数.结果 CCA、ICA的内径和CCA血流量的基础值B组比A组要大(P<0.05).与T0比较,在T1和T2时点,A组和B组CCA内径分别减少9.5%～12.9%和14.5%～24.3%(P<0.05或P<0.01),其中以B2组减少最为显著,A2组和B2组ICA内径分别减少10.9%和16.3%(P<0.05).CCA和ICA的血流速率无明显变化(P>0.05).与T0比较,A组和B组,T1和T2时CCA的血流量分别减少9.3%～10.7%和12.2%～19.1%(P<0.05),其中以B2组减少最为显著,A组和B组ICA血流量分别减少10.0%～13.5%和13.9%～16.6%(P<0.05).在T3时点各观察指标均恢复至T0水平.结论 喉罩通气时,CCA和ICA的内径有所缩小,其血流量相应减少,老年患者减少更为明显,而其血流速率则无明显改变.     

急性上肢哑铃训练对颈总动脉硬度和血液动力学的影响

抗阻力训练对于动脉硬度的影响存在着相互矛盾的结果。为研究不同负荷的急性上肢哑铃训练对颈总动脉硬度和血液动力学的影响,选择10名健康男性志愿者,年龄（21 ± 2）岁,分别进行5 kg和7 kg负荷的哑铃上肢曲臂训练各50次,两种负荷中间休息30 min。用彩色超声多普勒记录静息状态及不同哑铃负荷训练后颈总动脉的管径和轴心流速波形,用电子自动血压计同步测量心率和肱动脉血压。基于检测的实验数据,用经典血液动力学理论对颈总动脉硬度、压力-应变弹性模量以及相关血液动力学参数进行分析和计算。结果表明,受试者经过急性上肢哑铃训练后,心率、最大轴心流速、收缩压和最大壁面切应力等血液动力学参数明显增大,而颈总动脉管径、平均流量率、平均血压等参数没有明显变化。此外,在经过5 kg哑铃训练后,最大流量率和平均轴心流速显著增加,最小轴心流速显著减小,颈总动脉硬度、压力-应变弹性模量、舒张压、最小壁面切应力和振荡剪切指数无明显变化;而7 kg哑铃训练后,颈总动脉硬度、压力-应变弹性模量、振荡剪切指数明显增加,舒张压、最小壁面切应力显著降低,平均轴心流速和轴心流速最小值无明显变化。上肢急性哑铃训练会明显改变部分血液动力学参数,在高负荷训练时会急性增加颈总动脉的硬度。     

腹部枪伤时颈总动脉内血流动力学变化的模拟实验

为了探讨腹部枪伤时脑损伤的发生机制，本研究设计了模拟实验，在模拟腹部枪伤瞬间用压力传感器测试并计算了模拟总动脉内血流动力学变化。实验结果显示枪击瞬间颈总动脉内压力高，压力上升速度快，血流速度快，压差大，流量大。大量血流从颈总动脉急速涌向脑部必须导致脑部的损伤。     

锁骨下动脉、颈总动脉和椎动脉分叉处血流动力学数值模拟

目的:探讨锁骨下动脉、颈总动脉和椎动脉分叉处的血流动力学特性,分析该处发生血管狭窄引起大脑供血不足的 血流动力学原因。方法:采用内蒙古民族大学附属医院神经内科提供的CT数据,应用医学建模软件MIMICS20.0将患者 二维CT数据进行三维血管重建,经过网格划分及边界条件设置后导入计算流体力学软件FLUENT14.5中。计算和分析 不同血液入口速度的锁骨下动脉、颈总动脉和椎动脉分叉处的血流动力学特性。结果:在血液入口速度不同的情况下,锁 骨下动脉、颈总动脉和椎动脉分叉处的血液流场分布、血液压力分布和血管壁面切应力分布有显著变化。在血液入口速 度增大时,锁骨下动脉分叉处和颈总动脉分叉处的血液流速快、血管壁压力大,颈总动脉内侧血管壁面切应力大,但锁骨 下动脉分叉处和颈总动脉分叉处血管壁面切应力数值和变化幅度小,属于低切应力区。结论:通过血流动力学数值模拟 研究,分析锁骨下动脉、颈总动脉和椎动脉分叉处易发生粥样斑块病变导致大脑供血不足的血流动力学原因。     

颈总动脉血管粥样斑块与颅内血流速度关系

观察颈总动脉血管粥样斑块与该血管颅内供血区动脉血流速度变化的关系;方法颈部超声观察有粥样斑块者,用经颅多普勒超声观察该血管颅内供血区血流速度的变化;结果颈总动脉血管有粥样斑声者,颅内供血区动脉血管出现异常的机率增加,且两者有70%显示为高度相关.同时表明动脉内膜厚度改变较粥样斑块大小与血流速度异常相关明显;结论颈总动脉粥样斑块可明显影响该血管颅内供血区动脉血管的血液供应,并显示出动脉内膜厚度改变较粥样斑块大小变化对颅内血管血流速度影响更敏感.     

颈总动脉血管粥样斑块与颅内血流速度关系

观察颈总动脉血管粥样斑块与该血管颅内供血区动脉血流速度变化的关系;方法：颈部超声观察有粥样斑块,用经颅多普勒超声观察该血管颅内供血区血流速度的变化;结果：颈总动脉血管有粥样斑声,颅内供血区动脉血管出现异常的机率增加,且两有70％显示为高度相关。同时表明动脉内膜厚度改变较粥样斑块大小与血流速度异常相关明显;结论：颈总动脉粥样斑块可明显影响该血管颅内供血区动脉血管的血液供应,并显示出动脉内膜厚度改变较粥样斑块大小变化对颅内血管血流速度影响更敏感,     

弯曲颈总动脉内流场的模拟实验研究

目的模拟研究弯曲颈总动脉定常流动速度剖面的不对称性。方法用粒子图像测速技术(PIV)测量并分析曲率分别为1:60和1:20的90°弯管模型在颈总动脉生理平均雷诺数、峰值雷诺数和极限雷诺数条件下,在不同位置的弯曲平面及其垂直方向的轴向速度剖面。结果当颈总动脉的曲率等于1:60时,在人生理平均流动雷诺数条件下,颈总动脉的速度剖面可用偏斜的抛物面来近似;当颈总动脉曲率增大或流动雷诺数增大时,弯曲平面上的速度剖面中部出现下凹趋势,垂直方向上出现M型速度剖面;沿管轴不同位置上的速度剖面形状不同。结论为确定颈动脉分叉定常流动不对称入口速度剖面条件,认识速度剖面的形状如何随流动雷诺数、弯管曲率和截面位置变化提供实验依据。     

锥度角对弯曲动脉血管的血流动力学影响

运用血流动力学的基本原理和计算流体力学方法,对具有锥度角的弯曲血管内的血液二维定常流动流场进行数值模拟和分析.计算出具有锥度角的弯曲动脉内血液流动的压力和速度的分布情况.计算结果表明由于弯曲血管的曲率和沿血管渐缩的锥度角使得血管截面血流速度分布尤其是径向速度分布发生较大畸变;锥度角对弯曲动脉血管的血流动力学影响主要体现在对血流径向速度分布的影响.     

HPLC法比较心脏采血和颈总动脉采血对家兔水杨酸钠血浆半衰期的影响

目的:观察心脏采血和颈总动脉采血对家兔水杨酸钠血浆半衰期的影响.方法:将12只家兔按随机数字单盲法分为心脏采血组和颈总动脉采血组(n=6),经耳缘静脉注射10％水杨酸钠溶液2 ml·kg-1,分别于0 min,10 min和40 min后采血,处理血样,HPLC测定血浆水杨酸的峰面积,计算其半衰期.结果:心脏采血组半衰期比颈总动脉采血组明显延长(P＜0.05),颈总动脉采血组的实验数据较心脏采血组更为稳定.结论:颈总动脉采血较心脏采血对水杨酸钠半衰期的测定更为稳定.     

高血压与低切应力对大鼠颈总动脉血管重建的影响

目的研究高血压与低切应力对血管重建的影响及其机制,这对于阐明血管疾病的发病机理以及提供诊断、治疗的一些基本原理都将有重要的理论和实际意义。方法通过腹主动脉缩窄,结扎左颈总动脉的部分分支建立高血压、左颈总动脉低切应力以及高血压伴有低切应力大鼠动物模型。几何形态学方法观测左颈总动脉的壁厚及壁厚/内径比的变化;金属蛋白酶谱法分析MMP-2活性;免疫印迹法检测信号通路分子p-Akt分子以及Rho GDIα的表达变化。结果高血压和低切应力均可诱导颈总动脉MMP-2活性和壁厚及壁厚/内径比显著增加;当高血压伴有低切应力时,两者的协同作用诱导颈总动脉MMP-2活性和壁厚及壁厚/内径比进一步增加,从而促进血管重建。低切应力可诱导颈总动脉p-Akt的表达水平,且与低切应力大小相关,切应力低,p-Akt的表达水平高。当高血压伴有低切应力时,两者的协同作用诱导p-Akt的表达水平进一步增加。高血压和低切应力可诱导颈总动脉RhoGDIα表达增加;当高血压伴有低切应力时,两者的协同作用诱导颈总动脉Rho GDIα表达进一步增加。结论高血压与切应力协同作用对血管重建的影响最为显著,Akt和Rho GDIα信号通路参与了高血压与低切应力诱导的血管重建过程。     

Treatment of an acute mycotic aneurysm of the common carotid artery with a covered stent-graft

We report herein a case successful endovascular treatment with a stent-graft of a rare case of rapidly growing mycotic aneurysm of the left common carotid artery due to acute bacterial endocarditis after eradication of the infection. Infected mycotic aneurysms of the peripheral vasculature have been considered as a contraindication for stent-graft implantation because of the possibility of microorganism spreading to the stent-graft; however, if there is evidence of complete eradication of microorganism and surgery is not an option, stent-graft implantation can be an effective and safe treatment modality for exclusion of the mycotic aneurysm.     

Influence of different isoflurane anesthesia protocols on murine cerebral hemodynamics measured with pseudo‐continuous arterial spin labeling

Arterial spin labeling (ASL)‐MRI can noninvasively map cerebral blood flow (CBF) and cerebrovascular reactivity (CVR), potential biomarkers of cognitive impairment and dementia. Mouse models of disease are frequently used in translational MRI studies, which are commonly performed under anesthesia. Understanding the influence of the specific anesthesia protocol used on the measured parameters is important for accurate interpretation of hemodynamic studies with mice. Isoflurane is a frequently used anesthetic with vasodilative properties. Here, the influence of three distinct isoflurane protocols was studied with pseudo‐continuous ASL in two different mouse strains. The first protocol was a free‐breathing set‐up with medium concentrations, the second a free‐breathing set‐up with low induction and maintenance concentrations, and the third a set‐up with medium concentrations and mechanical ventilation. A protocol with the vasoconstrictive anesthetic medetomidine was used as a comparison. As expected, medium isoflurane anesthesia resulted in significantly higher CBF and lower CVR values than medetomidine (median whole‐brain CBF of 157.7 vs 84.4 mL/100 g/min and CVR of 0.54 vs 51.7% in C57BL/6 J mice). The other two isoflurane protocols lowered the CBF and increased the CVR values compared with medium isoflurane anesthesia, without obvious differences between them (median whole‐brain CBF of 138.9 vs 131.7 mL/100 g/min and CVR of 10.0 vs 9.6%, in C57BL/6 J mice). Furthermore, CVR was shown to be dependent on baseline CBF, regardless of the anesthesia protocol used.     

Effects of blood-volume distribution on the characteristics of the carotid baroreflex in humans at rest and during exercise

Seven supine subjects were studied at rest and during mild to moderate dynamic leg exercise with and without unloading of the cardiopulmonary baroreceptors accomplished by exposing the lower portion of the body to a subatmospheric pressure of 20 mmHg (Lower Body Negative Pressure, LBNP). The function of the cardiac branch of the carotid baroreflex was studied over its full operational range by measuring R-R intervals during application of pulse synchronous graded pressures (40 to – 65 mmHg) in a neck-chamber device. Raising the carotid transmural pressure (systolic arterial pressure minus neck-chamber pressure) induced increasing R-R intervals in all conditions. In conformity with previous results from our laboratories it was found that the maximal rate of change in relative R-R intervals and the corresponding transmural pressure were higher during exercise than at rest, indicating that exercise increased the carotid baroreflex sensitivity and shifted its optimal buffering range to higher arterial pressures. LBNP did not affect the characteristics of the reflex at rest nor during exercise. It is concluded that reduced central venous pressure with consequent selective cardiopulmonary receptor disengagement exerts no influence on the carotid baroreflex control of heart rate (HR), as tested over the entire arterial pressure-effector response relation, either at rest or during mild-moderate exercise.     

解除狭窄联合Rho激酶抑制剂对颈动脉狭窄大鼠认知功能的影响

目的 观察解除狭窄联合Rho激酶抑制剂对重度颈动脉狭窄大鼠认知功能(VCI)、海马区细胞凋亡及相关基因表达.方法 用48只SD大鼠,复制重度颈动脉狭窄模型,分成假手术组、狭窄解除组、药物组和联合组,另12只为对照组.联合组给予狭窄解除和法舒地尔(8.35 mg/kg),药物组注射等量的法舒地尔,狭窄解除组给予解除狭窄,对照组注射等容积的0.9％氯化钠注射液.分别在干预2和4周后,Morris水迷宫实验检测大鼠的空间学习记忆能力;免疫组化方法检测海马区凋亡相关蛋白BCL-2及BAX免疫阳性细胞数;TUNEL染色法检测海马区凋亡神经细胞.结果 与单纯药物组和狭窄解除组比较,联合治疗组大鼠的逃避潜伏期和游泳距离百分比均有显著改善(P＜0.05),海马区凋亡相关蛋白BCL-2免疫阳性细胞数显著增加(P＜0.05),而BAX的免疫阳性细胞数显著降低(P＜0.05),且治疗4周比2周更明显(P＜0.05);联合治疗组大鼠海马区的神经细胞凋亡率为56.24％±2.25％,明显低于药物治疗组和狭窄解除组的63.86％ ±2.23％和61.89％±2.67％(P ＜0.05),且随着治疗时间延长,细胞凋亡率呈下降趋势.结论 解除颈动脉狭窄联合Rho激酶抑制剂可通过调节凋亡相关蛋白的表达而明显改善颈动脉狭窄引起的认知功能障碍.     

Effects of percutaneous lower-extremity arterial interventions on endothelial function and inflammation response in patients with both type 2 diabetes and lower-extremity peripheral arterial disease

Background: The high incidence and damage of PAD in people with diabetes has aroused wide attention. We aimed to examine effects of percutaneous lower-extremity arterial interventions (PLEAIs) on endothelial function and inflammation response in type 2 diabetes (T2D) patients with lower-extremity peripheral arterial disease (PAD). Methods: 78 T2D inpatients with PAD were selected into the treatment group. Their venous levels of von Willebrand Factor (vWF) and high sensitivity C reactive protein (hsCRP) were measured. Blood samples were collected from the arterial sheath for vWF and hsCRP tests. Venous levels of vWF and hsCRP were monitored at 24 hours, 48 hours, 1 week, and 2 weeks post PLEAIs. Results: Prior to PLEAIs, venous levels of vWF and hsCRP in the treatment group were significantly higher than the control group. The arterial levels of vWF and hsCRP were 117.9%±15.1% and 5.19±0.76 mg/L in the control group, while those levels in the treatment group before intervention were also significantly higher than in the control group. In the treatment group prior to inventions, vWF and hsCRP levels of arterial ischemic regions were significantly higher than the non-ischemic regions. The vWF level of arterial ischemic regions after treatment was significantly higher than that prior to treatment. Conclusions: PLEAIs applied to those patients may lead to worse endothelial dysfunction and activated inflammatory response during treatment and 1 week after treatment, which indicates an emerging necessary of early protection or care on endothelial function and inflammatory reaction during and post PLEAIs.