Microvascular disturbances in the colonic mucosa in antibiotic-associated haemorrhagic colitis: Involvement of platelet aggregation

An ultrastructural study of the colonic mucosa was performed in four patients with antibiotic-associated haemorrhagic colitis and new findings are reported. Colonoscopy was performed and biopsy specimens were obtained within 24 h of the onset of bloody diarrhoea. Colonoscopy demonstrated diffuse oedematous and haemorrhagic mucosa with erosions and white coat. Light microscopy revealed mucosal haemorrhage and inflammatory cell infiltration. Ultrastructurally, platelet aggregation was frequently present in the lumina of colonic mucosal capillaries, causing engorgement of red blood cells in adjacent microvessels. Mild to severe damage was observed in capillary endothelial cells, including discontinuity of basement membranes, gaps between endothelial cells and the destruction of capillaries. There was no evidence of microvascular spasm. In conclusion, our findings suggest that antibiotics directly or indirectly cause microcirculatory disturbances, which result in tissue damage and haemorrhage, in the colonic mucosa.     

Effect of injury to the microvessels on the frequency of tumor cell lodgment in them

The action of local laser injury to the microvessels on the frequency of lodgment of tumor cells and on the ability of the cells to migrate from the lumen of the vessel was studied. A television microscope with video tape recorder and UV-laser were used. Cells of a Zajdela's ascites hepatoma were injected into the blood stream of a rat. Lodgment of tumor cells in the mesenteric vessels was observed infrequently (11%). The lodged cells adhered to the vessel wall and migrated from its lumen. Injury to the vessel wall by the laser beam led to the formation of microthrombi and to an increase in the frequency of lodging of the tumor cells in the vessels: 82% instead of 11%. The frequency of migration of cells from the lumen of the vessel under these circumstances, however, was reduced. The results confirm the role of microthrombus formation in metastasization; however, the role of microthrombus formation mav be exerted in different directions for although the frequency of adhesion of the tumor cells is increased, their mobility is reduced for a few a few hours after lodging in the microvessels.Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 7, pp. 859–861, July, 1976.     

Changes in myocardial metabolism and ultrastructure of myocardial microvessels during pharmacological and cold cardioplegia under hypothermic conditions without perfusion

A combination of pharmacological and cold cardioplegia in with hypothermia without perfusion in open-heart surgery guarantee the reversible character of shifts in energy and free radical balance in the myocardium. However, this procedure can impair coronary micricirculation due to structural and functional changes in microvessel endothelium. Our results demonstrate that new cytoprotective approaches are extremely needed for cardiac protection during surgery.     

针刺对变应性鼻炎患者血浆内皮素及鼻粘膜微血管的影响

目的对３３例常年性变应性鼻炎患者进行针刺治疗,以观察其对血浆内皮素（ｅｎｄｏｔｈｅｌｉｎ,ＥＴ）及鼻粘膜微血管的影响。方法①血浆ＥＴ测定：采用特异性放射免疫法（均相竞争法）直接测定血浆ＥＴ含量。②鼻粘膜微血管的观察：主要观察鼻粘膜微血管管径、管袢数及鼻粘膜微血管的形态。③针刺治疗：选择曲池、血海两穴进行针刺。结果变应性鼻炎患者鼻粘膜微血管管径针刺后较针刺前增粗;针刺后变应性鼻炎患者鼻粘膜微血管形态变化以灯丝状微血管增多、网络状微血管减少为特征;变应性鼻炎患者鼻粘膜微血管管袢数针刺后较针刺前增多;变应性鼻炎患者针刺后血浆ＥＴ含量明显降低。结论变应性鼻炎针刺后鼻粘膜微循环明显改善,表现为鼻粘膜微血管管径增粗,灯丝状微血管增多、网络状微血管减少,管拌数增加,并与血浆ＥＴ存在密切关系,其机理可能是通过降低血浆ＥＴ的水平而起作用的。     

高盐诱导自发性高血压大鼠脑出血及脑微血管构筑改变

目的 探讨自发性高血压大鼠(spontaneously hypertensive rats,SHR)和正常血压大鼠(Wistar-Kyoto rat,WKY)饲喂高盐饮食后脑出血特点及脑微血管结构改变.方法 6周龄雄性SHR和WKY大鼠各60只分别通过随机数字表分为两组,一组饲喂高盐饮食,一组饲喂常规饮食,每周测1次尾动脉收缩压,观察大鼠行为学改变、存活情况、神经功能缺损并评分,HE染色观察脑出血后血肿特点,干湿质量比法测定脑含水量,伊文氏蓝(Evans blue,EB)检测血脑屏障通透性,免疫荧光染色观察脑微血管改变,透射电镜观察脑微血管超微结构和紧密连接改变.结果 与两组常规饮食大鼠相比,两组高盐饮食大鼠均出现血压升高、神经功能缺损症状,脑含水量和血脑屏障通透性增加,HE染色可见血管周围出现圆形渗出性出血,免疫荧光染色显示脑血管呈断续性改变,透射电镜可见脑血管与周围组织间隙增宽,紧密连接消失,管壁厚薄不均,出现空泡样改变.SHR所有改变较WKY显著(P＜0.01).高盐饮食SHR 18周龄时全部死亡,高盐饮食WKY 19周龄时全部死亡,常规饮食大鼠均正常存活.结论 高盐可单独引起大鼠血压升高、脑微血管结构改变,高血压可加重大鼠脑微血管损伤,两者可共同促进大鼠脑出血发生.     

Possible correction of lymph flow and contractile activity of lymphatic microvessels during febrile response

In experiments on dogs and rats dimephosphon considerably enhanced contractile activity of walls and valves in lymphatic microvessels, thus accelerating lymph flow and improving exchange between blood and lymph.