Increased activity of Rho kinase contributes to hemoglobin-induced early disruption of the blood-brain barrier in vivo after the occurrence of intracerebral hemorrhage

This study is to examine whether the activation of Rho kinase (ROCK) accounts for hemoglobin (Hb)-induced disruption of blood-brain barrier (BBB) after the occurrence of intracerebral hemorrhage. A model of intracerebral injection of Hb was established in rats. Changes in the levels of mRNA of RhoA, ROCK2 and matrix metalloproteinase-9 (MMP-9) were measured using quantitative real-time polymerase chain reaction. Protein expression of RhoA, ROCK2, claudin-5 and MMP-9, as well as ROCK activity, were determined using Western blotting. Immunohistochemical assay was performed to visualize the expression of RhoA, ROCK2, claudin-5 and MMP-9 in endothelial cells. Hb injection produced a significant increase in BBB permeability and water content in the brain. Significant reduction of claudin-5 expression was detected by Western blotting and immunofluorescence in Hb group. The levels of RhoA and ROCK2 were significantly up-regulated from 6 h to 12 h after Hb injection and were concomitant with the increase in ROCK activity. Immunofluorescence double staining showed enhanced p-myosin light chain immunoreactivity but diminished claudin-5 staining in endothelial cells. Significant up-regulation of MMP-9 expression was detected after Hb injection, and statistical analyses further confirmed a positive correlation of MMP-9 expression with ROCK activity. The results showed that ROCK was activated in endothelial cells by Hb. This may account for the early disruption of the BBB via up-regulation of p-myosin light chain expression and aggravation of injuries to TJ proteins. The activation of ROCK may also increase MMP-9 expression, thereby leading to further BBB disruption.     

乳果糖口服液对肝硬化患者肝功能和肠黏膜屏障功能的影响分析

目的探讨和分析乳果糖口服液对肝硬化患者肝功能和肠黏膜屏障功能的影响。方法将我院84例肝硬化患者随机分为对照组和观察组,对照组给予呋塞米注射液、甘草酸二胺注射液治疗,观察组患者在此基础上给予口服乳果糖口服液,观察对比治疗前后2组患者肝功能和肠黏膜屏障功能的变化情况。结果治疗后,2组患者的ALT、AST、TB、血清内毒素、D-乳酸、PCT水平较治疗前均明显改善(P0.01),且观察组治疗后的肝功能和肠黏膜屏障功能各项指标均明显优于对照组(P0.01)。结论乳果糖可改善肝功能和肠黏膜屏障功能的各项指标,阻止肝硬化病情恶化,提高患者生活质量。     

The importance of temperature on the neurovascular unit

Therapeutic hypothermia is the only treatment that has been shown to be of benefit to infant's ≥ 36 weeks of gestation with hypoxic–ischemic encephalopathy. The evidence for the benefit is based on multiple, well-designed randomized clinical trials. Based on this data, the use of therapeutic hypothermia has been widely disseminated throughout the neonatal community. An important concept in hypoxic–ischemic brain injury is the functioning of the neurovascular unit which links neurons, non-neuronal cellular elements and the capillary endothelial cells to promote optimal barrier maintenance between the brain and systemic circulation, regulation of blood flow and neuro-immunologic functioning. Hypoxic–ischemic injury can trigger increased permeability of the blood‐brain-barrier via molecular events within the neurovascular unit and initiate pathways to brain injury. In addition, exposure of the brain to cellular elements from the systemic circulation can further propagate the neuro-inflammatory response. The influence of temperature on injury to the neurovascular unit has received relatively little attention. This review will focus on one component of the neurovascular unit, the blood‐brain barrier and its constituents. Specifically, this review will address the effects of hypoxia–ischemia and temperature on the neurovascular unit and potential knowledge gaps which may serve as areas for further investigation.     

Histocytological study of the guided bone regeneration using the rat mandible

Histological changes, localization of osteoblasts, and activating time at defective areas of rat mandible were studied with the GBR technique using absorptive (dura mater) and non-absorptive (GTAM) barrier membrane. We examined the rat-mandibles which had been operated by the GBR technique and obtained following results:

A prospective clinical study of bone augmentation techniques at immediate implants

The efficacy of combinations of membranes and autogenous bone grafts at immediate implants were compared in a prospective study. Sixty-two consecutively treated patients each received an immediate implant for a single tooth replacement at a maxillary anterior or premolar site. Dimensions of the peri-implant defect at the implant collar were measured as follows: vertical defect height (VDH), horizontal defect depth (HDD) and horizontal defect width (HDW). Each implant randomly received one of five augmentation treatments and were submerged with connective tissue grafts: Group 1 (n=12)--expanded polytetrafluoroethylene membrane only, Group 2 (n=11)--resorbable polylactide/polyglycolide copolymer membrane only, Group 3 (n=13)--resorbable membrane and autogenous bone graft; Group 4 (n=14)--autogenous bone graft only, and Group 5 (n=12)--no membrane and no bone graft control. At re-entry, all groups showed significant reduction in VDH, HDD and HDW. Comparisons between groups showed no significant differences for VDH (mean 75.4%) and HDD (mean 77%) reduction. Significant differences were observed between groups for HDW reduction (range, 34.1-67.3%), with membrane-treated Groups 1, 2 and 3 showing the greatest reduction. In the presence of dehiscence defects of the labial plate, HDW reduction of 66.6% was achieved with membrane use compared with 37.7% without membranes. Over 50% more labial plate resorption occurred in the presence of a dehiscence defect irrespective of the augmentation treatment used. The results indicate that VDH and HDD reduction at defects adjacent to immediate implants may be achieved without the use of membranes and/or bone grafts.