Microcirculation and excretory function of the liver under conditions of carbon dioxide pneumoperitoneum

Background: To date, the effects of increased abdominal pressure, as given during carbon dioxide (CO₂) pneumoperitoneum, on hepatic microcirculation and biliary excretion are unknown.Methods: Using a custom-made peritoneal cavity chamber, we performed intravital microscopy of the left liver lobe under conditions of CO₂ pneumoperitoneum in a rat model. In addition, biliary excretion was assessed.Results: The establishment of a CO₂ pneumoperitoneum of 4 or 8 mmHg resulted in sinusoidal perfusion failure that was more pronounced in the periportal regions than in the midzonal and pericentral regions of the liver acinus. Biliary excretion was considerably reduced at an intraabdominal pressure of 8 mmHg. Leukocyte–endothelial cell interactions increased significantly in both hepatic sinusoids and postsinusoidal venules.Conclusion: Alterations in hepatic microcirculation and liver function must be taken into consideration in any kind of laparoscopic surgery and may be of particular clinical relevance in patients with liver pathology.     

Ischemic preconditioning fails to improve microcirculation but increases apoptotic cell death in experimental pancreas transplantation

Brief periods of warm ischemia and subsequent short reperfusion before either long-term cold or warm ischemic insult (ischemic preconditioning, IPC) have proven to ameliorate ischemia/reperfusion (I/R) injury in various organs, such as the liver and lung. The aim of this study was to examine the effect of IPC on pancreatic cell apoptosis and microcirculatory impairments in experimental pancreas transplantation. Male Lewis rats served as donors and recipients of heterotopic syngeneic pancreaticoduodenal transplantation. Recipient animals were divided into two experimental groups: group Tx (n=7) received grafts without IPC, group Tx&IPC received grafts with IPC. Animals that had not undergone transplantation but whose pancreata had been exteriorized served as controls (n=5). All pancreatic grafts were preserved in University of Wisconsin solution for 6 h at 4°C. IPC was induced by interruption of the arterial blood flow for 10 min followed by 10 min of reperfusion. One and two hours after reperfusion, graft microcirculation was assessed by means of intravital microscopy (IVM). Rats were immediately killed after the second measurement and DNA breaks of acinar cells were detected by in situ terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate digoxigenin nick end-labelling (TUNEL) assay and gel electrophoresis (laddering). The apoptotic index (AI) was defined as the number of apoptotic cells per high-power field. Analysis of both groups of transplanted grafts showed a significant decrease in functional capillary density (FCD) and a significant increase in leukocyte sticking to postcapillary venules (LAV) at 1 h and 2 h of reperfusion, compared with animals that had not undergone transplantation (P<0.01). In parallel, AI was significantly increased in transplanted grafts compared to the controls (P<0.01). Grafts subjected to IPC showed no significant differences, neither for FCD nor LAV, at both time points if compared with grafts of group Tx. However, IPC resulted in a significant increase in AI (P<0.05). We can conclude that IPC has no effect on pancreatic microcirculation but enhances acinar cell apoptosis in experimental pancreas transplantation. These results indicate that IPC might increase I/R injury after pancreatic cold ischemia.     

方剂突聋灵治疗光化学诱导法致豚鼠突发性聋的实验研究

目的:探讨中药方剂突聋灵治疗光化学诱导法所致豚鼠突聋效果。方法:采用光化学诱导法建立豚鼠耳蜗微循环障碍诱发突聋模型36只,随机均分为正常对照组,单纯造模组,中药给药A组和中药给药B组。以听性脑干反应阈值变化和耳蜗外侧壁铺片为观察指标,观察中药突聋灵对听力的作用及血管纹的变化。结果:中药组动物ABR反应阈值较单纯造模组明显降低(P<0.01),耳蜗外侧壁铺片显示血管纹毛细血管网萎缩明显好转。结论:方剂突聋灵改善耳蜗微循环效果良好。     

糖尿病早期大鼠视网膜微血管改变的形态学研究

目的研究糖尿病早期大鼠视网膜微循环的形态学改变及白细胞在糖尿病视网膜病变（ｄｉａ－ｂｅｔｉｃｒｅｔｉｎｏｐａｔｈｙ，ＤＲ）微循环障碍中的作用。方法雄性成年Ｗｉｓｔａｒ大鼠１２只，随机分为正常对照组、链脲佐菌素（ｓｔｒｅｐｔｏｚｏｔｏｃｉｎ，ＳＴＺ）糖尿病大鼠３、６个月组各４只。动物活体灌注固定，视网膜消化铺片，光镜观察，计数周细胞并行统计分析。结果糖尿病大鼠６个月组视网膜毛细血管周细胞数明显减少，并见毛细血管有白细胞栓塞。结论大鼠注射ＳＴＺ后６个月出现ＤＲ的早期改变，白细胞栓塞毛细血管形成ＤＲ微循环障碍。     

熄风康的药理研究

实验结果表明，熄风康能显著抑制大鼠血小板聚集及体内血栓形成，改善小鼠耳郭微循环，对小鼠急性脑缺血有明显的保护作用     

慢性阿片类耐受、戒断状态下的微循环改变及温阳益气活血复方的作用

目的探讨机体微循环在阿片类耐受、戒断过程中的不同变化,探讨温阳益气活血复方抗戒断症状的作用机理;方法应用高倍显微电视放大技术和甲襞微循环分析仪,观察慢性吗啡耐受、戒断大鼠及海洛因依赖者微循环变化;结果耐受大鼠提睾肌A_3和V_3中RBC聚集成长链状,呈粒流或缓粒流,V_3壁有大量WBC粘附、嵌塞,戒断7日大鼠的微循环状态与耐受大鼠比较无明显变化,复方能显著改善戒断大鼠紊乱的微循环。海洛因依赖者的微循环出现管袢顶淤滞、变窄明显,管袢数目减少,长度缩短;白细胞增多,红细胞聚集,血流速度减慢等改变,复方对紊乱的微循环有极其显著的稳定作用。结论阿片类确能引起机体微循环的改变,且在戒断后一段时间仍不能恢复,温阳益气活血复方可恢复紊乱的微循环。临床辨治时,活血化瘀药物的配用可疏通瘀滞的微循环,使毒品易于排出体外,对后续稽延症状的治疗有积极的意义。     

慢性鼻窦炎患者上颌窦粘膜微循环观察

目的:探讨慢性鼻窦炎患者上颌窦粘膜微循环血流量的变化。方法:在鼻窦内窥镜引导下应用激光多普勒血流计检测10例慢性单纯性鼻窦炎患者(慢性单纯性鼻窦炎组),10例慢性鼻窦炎伴鼻息肉患者(慢性鼻窦炎伴鼻息肉组)及10例健康者(正常对照组)上颌窦粘膜微循环血流量的状况。结果:慢性单纯性鼻窦炎组和慢性鼻窦炎伴鼻息肉组上颌窦粘膜的微循环血流量均下降,分别与正常对照组相比较,其差异均有显著性意义(分别为P<0.05和P<0.01),但两组间比较,其差异无显著性意义(P>0.05)。结论:慢性鼻窦炎患者上颌窦粘膜微循环血流量明显减少。     

Modification of alpha-adrenergic responses of small arteries by altered PCO2 and pH.

Closed-circuit television microscopy was used to measure in vivo small artery (75--140 microns) and vein (105--230 microns) diameters to determine if changes in tissue PCO2 and/or pH would alter the microvascular responses to norepinephrine. Sprague-Dawley rats were anesthetized with a combination of urethane (800 mg/kg) and alpha-chloralose (60 mg/kg). The cremaster muscle with intact circulation and innervation was suspended by sutures in a 60-ml bath which contained a modified Krebs solution (31 degrees C) that was buffered by Tris of bicarbonate. There were four groups of animals with different combinations of bath PCO2 and pH: (1) PCO2 less than 10 mm Hg and pH = 7.2, (2) PCO2 less than 10 mm Hg and pH = 6.9, (3) PCO2 = 60--70 mm Hg and pH = 7.2, and (4) PCO2 = 60--70 MM Hg and pH = 6.9. The maximal responses of the small artery and vein to norepinephrine were similar for the four groups. The artery sensitivity to norepinephrine was significantly lower for group 4 when compared to groups 1, 2 and 3, but there was no effect on small vein sensitivity. Thus, the combination of decreased pH and increased PCO2 reduces small artery sensitivity to norepinephrine in the cremaster muscle of the rat.     

Cortical oxygen pressure during acute venous kindney obstruction

Summary Different degrees of obstruction to the renal venous drainage were produced in rabbits and the cortical oxygen pressures in the kidney measured with the multiple-wire surface electrode of Kessler and Luebbers. Sudden complete occlusion of the inferior vena cava (IVC) above the renal vein, or above and below the renal vein simultaneously, produced a slight decrease of about 27%. Sudden complete occlusion of the renal vein itself caused a severe decrease of 67% (obstruction near the IVC) or 100% (obstruction near the kidney). One hour later different degrees of incomplete recovery were found. The PO₂ curves for the renal cortex revealed different pressure-dependent pathophysiological changes in the microcirculation. The multiple-wire surface electrode may well prove to be of use during renal surgery in which venous obstruction is a critical factor.     

Measurement of the skin microcirculation through intact bandages using laser Doppler flowmetry

The microcirculation under compression bandages has been assessed by numerous methods; however, the measurement techniques can disrupt the bandage-skin interface, affecting the measurement. In this study, a non-invasive method for measuring cutaneous blood flow using laser Doppler flowmetry (LDF) is presented. Ten volunteers had their microcirculation assessed by a laser Doppler probe being placed on their upper forearm with and without a light-transmissive gel and with a compression bandage plus light-transmissive gel. A circulatory challenge to the bandaged forearm in two of the volunteers was also undertaken. The median (95% confidence interval) perfusion (p.u.) for the skin surface was 24 (15–33) perfusion units (p.u.), and the skin plus light-transmissive gel demonstrated a higher perfusion: 66 (50–82) p.u., (p<0.012). The addition of the compression bandage, with additional gel allowed to permeate through to the underlying skin, decreased the perfusion to 27 (20–34) p.u. (p<0.007). In both volunteers, the microcirculatory flow responded to the vascular challenge, resulting in flow changes related to the cuff pressure (45-27 and 14-8 p.u.). This method demonstrated that it may be possible to assess the microcirculation through intact bandages, without the need to place any sensors at the skin-bandage interface.