Changes in some rheological properties of the blood after resuscitation

In experiments on cats anesthetized with pentobarbital, the dynamic viscosity of the blood and the aggregative power of the blood cells were studied during the first 2 h after resuscitation by means of a capillary loop viscosimeter. An increase in viscosity was found both in the zone of small (1.82 dyn/cm²) and in the zone of large (10.94 dyn/cm²) shear stresses. The increase in the hematocrit index and in the aggregative power of the blood cells plays a definite role in the increase in viscosity.     

Importance of nitric oxide in hepatic arterial blood flow and total hepatic blood volume regulation in pigs

The importance of nitric oxide in regulating basal arterial blood flow has been examined in several different vascular beds by intra-arterial infusion of inhibitors of nitric oxide synthesis, but not in the arterial vascular bed of the liver. In the present study, N^G-nitro-L -arginine (L -NNA), in a dose of 0.5 and 1.0 μmol mL^?1 of hepatic arterial blood flow, was infused for 5 min into the hepatic artery in seven pigs anaesthetized with pentobarbital sodium. The haemodynamic effects observed by the first infusion were not further enhanced by the second infusion. Hepatic arterial resistance increased by 143 ± 38% and hepatic arterial blood flow declined by 38 ± 10%. A systemic effect due to `spillover' was observed, as evidenced by an increase in mean aortic blood pressure of 24 ± 4 mmHg. However, no significant increase in arterial mesenteric resistance was observed and total liver blood flow remained unchanged. Hepatic arterial vasodilation in response to occlusion of the portal vein, the arterial buffer response, remained intact after inhibition of nitric oxide synthesis. Liver lobe thickness, measured by an ultrasonic technique,was not found to change with inhibition of arterial nitric oxide synthesis, excluding a significant direct effect of arterial nitric oxide on liver capacitance. In conclusion, nitric oxide is an important regulator of hepatic arterial resistance, but does not mediate the hepatic arterial buffer response and was not found to play any significant role in total hepatic capacitance regulation.     

冠状动脉微栓塞后冠脉血流储备及心肌血流量的变化及其机制

目的:经导管建立冠状动脉微栓塞模型,测定微栓塞后冠脉血流储备及心肌血流量的变化情况,并探讨其机制。方法:12只小型猪,通过导管方法建立急性冠脉微栓塞模型,观察急性期（基础、微栓塞后2 h、6 h）及慢性期（基础、微栓塞后1周）冠脉血流储备和心肌血流量的变化情况,并测定血清中内皮素-1（ET-1）浓度变化。结果:急性期冠脉微栓塞后冠脉血流储备在基础、微栓塞后2 h、6 h分别为2.10±0.60、1.40±0.10及1.10±0.10（微栓塞后2 h及6 h与基础相比,均P<0.01）,慢性期实验中,冠脉血流储备在微栓塞前及微栓塞后1周分别为2.03±0.43及1.58±0.22（微栓塞后1周与基础相比,P<0.05）。但前内侧和后内侧心肌血流量以及它们的比值在微栓塞后没有显著变化。测定血清ET-1浓度显示微栓塞后2 h开始升高,但只有微栓塞后6 h较基础有明显增加(P<0.05),微栓塞后6 h及1周心脏标本NBT染色均未见梗死灶。结论:冠脉微栓塞后冠脉血流储备呈现先下降后恢复的趋势,这种变化与内皮功能变化一致,冠脉血流储备和心肌血流量变化不同步。     

光照后胎儿脐动脉与脑动脉血流变化

为了证实胎儿对经母腹壁光照可产生应答反应，我们通过彩色多谱勒超声诊断仪观察了30名妊娠34-41周孕妇的胎儿，光照前后脐动脉、脑动脉血流变化。结果显示：光照后胎儿脐动脉及脑动脉血流量增加，经统计学处理有高显著性差异（P＜0．001），而动脉血流阻抗指数（RI）无差异性改变（P＞0．05）。说明血液流量增力。是由动脉压升高引起，而光照刺激使胎儿产生视觉，引起胎儿植物性神经功能的情绪反应，使交感神经系统活动相对亢进，是动脉压升高的原因。光照后胎儿脐动脉、脑动脉平均血流速度增加亦有高显著性差异（P＜0．001），而动脉血流速度指数（S／O）无差异性改变（P＞0．05）。说明本组胎儿的循环状态良好，光照后胎儿出现血液动力学上的明显变化，正是胎儿对光照产生的应答反应。这一研究成果为光照胎教方法提供了科学的依据。     

Regulation of hepatic blood flow in patients with liver cirrhosis and after liver transplantation

We studied liver blood flow at rest and its regulatory changes after exercise and food intake in ten patients with advanced liver cirrhosis and in 14 patients more than 10 months after orthotopic liver transplantation. The results were compared with those obtained in ten healthy volunteers. Sorbitol steady state infusion was employed to measure functional liver blood flow (FLBF). Thirty minutes of half-maximal muscular work, performed on a supine position ergometer and consumption of a standard meal were used as stimuli to study regulatory changes in hepatic perfusion. Results: FLBF at rest was reduced in end stage cirrhosis (mean 1257±105 ml/min in cirrhosis vs. 1707±76 ml/min in controls; P<0.01). After liver transplantation FLBF at rest was normalized (mean 1922±169 ml/min) in patients with stable graft function. Muscular exercise led to a reduction in FLBF, which in the transplanted patients was the same range as in normal controls (−26.7±3.7%; −24.7±0.7, respectively), but was reduced in cirrhosis (−19.1±2.1%; P<0.05). After ingestion of a standard meal FLBF increased substantially in normal controls (+40.2±2.3%), while in patients with cirrhosis this increase was rather small (+10.1±1.9%; P<0.001). After transplantation the food-induced increase in FLBF(+20.5±3.6%) was larger than in cirrhosis (P<0.05) but remained smaller than in the controls (P<0.01). We conclude that in cirrhosis FLBF is reduced and adaptive changes after exercise or food intake are impaired. After transplantation FLBF is normalized, but blood flow regulation, especially after food intake remains abnormal.     

Evaluation of disorders of portal and total hepatic blood flow in patients with chronic diffuse liver diseases

The total hepatic blood flow measured with radioactive colloidal gold and the portal blood flow with the echo-Doppler method were investigated in 19 healthy examinees and 63 patients with chronic diffuse liver diseases. In the group of healthy examinees, the average values of the total hepatic blood flow was 1254 +/- 231 ml/min and of the portal one 1104 +/- 227 ml/min. The lowest blood flow values were obtained in patients with decompensated cirrhosis, especially in the hepatic (704 +/- 186 ml/min) and the portal blood flow (562 +/- 198 ml/min). In all the groups of examinees, registered values of the total hepatic blood flow were significantly higher than the values of the portal blood flow. The relations of the values obtained by both methods, among groups, were similar. By both methods decreased values are not obtained in liver steatosis and chronic persistent hepatitis in relation to the normal values. In patients with more serious forms of chronic diffuse liver diseases (cirrhosis and chronic active hepatitis) significantly lower blood flow values than the normal ones were obtained. Both methods contribute to the investigation of liver circulation disturbances, liver function damages, and to the follow-up of the liver disease course. The possibility of an indirect evaluation of the arterial hepatic blood flow from the difference of hepatic and portal blood flows may mean a new approach to the investigation of pathophysiological liver occurrences.     

脂肪肝对小鼠肝血窦内血流状况的影响

目的 由于脂肪肝状态下肝细胞的体积变化可能导致肝内血液流动特征改变,本研究拟通过观测肝内的形态学、血流速度和迂曲度的变化,为脂肪肝的诊治提供帮助。 方法 小鼠背部皮下注射四氯化碳或橄榄油溶液建立脂肪肝模型,取小鼠肝组织进行HE与油红O染色;采用激光多普勒仪测量肝左叶浅表血管内的血流速度;小鼠尾静脉注射德克萨斯红荧光染料,双光子荧光显微镜下观察及测量小鼠肝血窦内红细胞的流动速度及血管内径状况,并进行肝血窦迂曲度检测。 结果 给予小鼠四氯化碳注射2周（n=16）和4周（n=16）后,油红O染色可见肝细胞内出现不同程度的红色脂滴沉积,且主要集中在中央静脉周围,肝血窦存在明显的变形和缩窄,且4周组更加明显。随着模型制作时间的延长,肝左叶的的浅表区域和肝血窦内的血流速度逐渐降低,且肝血窦的内径变小,迂曲度增加。 结论 脂肪肝状态下,肝血窦内径减小,血窦内血流速度下降,迂曲度增加,为脂肪肝早期诊断和治疗提供了可视化的形态学实验依据。     

正常人重复经颅磁刺激后脑血流速度的变化

目的 :探讨重复经颅磁刺激 (rTMS)对正常人脑血流速度的影响。方法 :对 12位健康受试者左额叶进行高频rTMS ,并用经颅多普勒超声仪 (TCD)观察其脑血流速度变化。结果 :正常人rTMS后 ,除左右大脑后动脉及椎动脉外 ,平均血流速度 (Vm)均有不同程度的增加 ,以左侧大脑前动脉及左侧大脑中动脉Vm的增加尤为明显 (P <0 0 5 ) ;刺激过程中无明显不适。结论 :rTMS能增加脑血流速度 ,且在一定的刺激强度和刺激频率范围内 ,具有安全性     

Non-homogeneous blood flow distribution in the rabbit tenuissimus muscle Differential control of total blood flow and capillary perfusion

Structural and functional relationships underlying the blood flow distribution in the rabbit tenuissimus muscle were examined by means of intravital microscopy. A majority of the main feeding arterioles (transverse arterioles) continued into adjacent connective tissue, after giving off branches (terminal arterioles) within the muscle tissue to supply the muscle capillaries. The transverse arterioles thus supplied two vascular areas, although the major part of the arteriolar flow, under normal resting conditions, was distributed to the muscle capillaries—a flow fraction over which the terminal arterioles exerted ultimate control. The fractional distribution of the blood flow between muscle and connective tissue was determined by the relative contributions of the transverse and terminal arterioles to the vascular resistance. These arteriolar segments showed a differential response to an increase in oxygen availability (elevated ambient pO₂), resulting in a total reduction of muscle capillary flow, but no concomitant change in the flow to connective tissue. A decrease in perfusion pressure, on the other hand, led to similar flow changes in the muscle and connective tissue circulation, which was attributed to proportionate resistance changes in the transverse and terminal arterioles. Differences between the larger transverse and smaller terminal arterioles in their sensitivity to various stimuli may form a functional basis for a differential control of arteriolar blood supply and capillary perfusion in this muscle.     

Changes in the tissue blood flow in the rabbit brain after burn,acute radiation,and combined injuries

The tissue blood flow of the brain was determined in experiments on rabbits with the aid of xenon-133 after severe burns affecting 20% of the body surface, whole-body x-ray irradiation in a dose of 900 rad, and combined exposure to both factors. The cerebral blood flow was found to be reduced by a lesser degree in burns than the minute volume of the heart (on the average by 20–30% and 50%, respectively). In combined trauma the decrease in the cerebral blood flow was the same as with isolated burns or radiation injury. The authors suggest that a greater decrease in the cerebral blood flow is incompatible with life. The results are evidence of the existence of compensatory mechanisms aimed at maintaining the cerebral blood flow despite a fall in the minute volume of the heart.