Memory T cell–mediated rejection is mitigated by FcγRIIB expression on CD8+ T cells

Donor‐reactive memory T cells generated via heterologous immunity represent a potent barrier to long‐term graft survival following transplantation because of their increased precursor frequency, rapid effector function, altered trafficking patterns, and reduced reliance on costimulation signals for activation. Thus, the identification of pathways that control memory T cell survival and secondary recall potential may provide new opportunities for therapeutic intervention. Here, we discovered that donor‐specific effector/memory CD8⁺ T cell populations generated via exposure to acute vs latent vs chronic infections contain differential frequencies of CD8⁺ T cells expressing the inhibitory Fc receptor FcγRIIB. Results indicated that frequencies of FcγRIIB‐expressing CD8⁺ donor‐reactive memory T cells inversely correlated with allograft rejection. Furthermore, adoptive T cell transfer of Fcgr2b^?/? CD8⁺ T cells resulted in an accumulation of donor‐specific CD8⁺ memory T cells and enhanced recall responses, indicating that FcγRIIB functions intrinsically to limit T cell CD8⁺ survival in vivo. Lastly, we show that deletion of FcγRIIB on donor‐specific CD8⁺ memory T cells precipitated costimulation blockade‐resistant rejection. These data therefore identify a novel cell‐intrinsic inhibitory pathway that functions to limit the risk of memory T cell–mediated rejection following transplantation and suggest that therapeutic manipulation of this pathway could improve outcomes in sensitized patients.     

Brain‐dead donor heart conservation with a preservation solution supplemented by a conditioned medium from mesenchymal stem cells improves graft contractility after transplantation

Hearts are usually procured from brain‐dead (BD) donors. However, brain death may induce hemodynamic instability, which may contribute to posttransplant graft dysfunction. We hypothesized that BD‐donor heart preservation with a conditioned medium (CM) from mesenchymal stem cells (MSCs) would improve graft function after transplantation. Additionally, we explored the PI3K pathway's potential role. Rat MSCs‐derived CM was used for conservation purposes. Donor rats were either exposed to sham operation or brain death by inflation of a subdural balloon‐catheter for 5.5 hours. Then, the hearts were explanted, stored in cardioplegic solution‐supplemented with either a medium vehicle (BD and sham), CM (BD + CM), or LY294002, an inhibitor of PI3K (BD + CM + LY), and finally transplanted. Systolic performance and relaxation parameters were significantly reduced in BD‐donors compared to sham. After transplantation, systolic and diastolic functions were significantly decreased, terminal deoxynucleotidyl transferase‐mediated dUTP nick end‐labeling (TUNEL)‐positive cells and endonuclease G positive cells were increased in the BD‐group compared to sham. Preservation of BD‐donor hearts with CM resulted in a recovery of systolic graft function (dP/dt_max: BD + CM: 3148 ± 178 vs BD: 2192 ± 94 mm Hg/s at 110 µL, P < .05) and reduced apoptosis. LY294002 partially lowered graft protection afforded by CM in the BD group. Our data suggest that PI3K/Akt pathway is not the primary mechanism of action of CM in improving posttransplant cardiac contractility and preventing caspase‐independent apoptosis.     

Contrasting effects of B cell depletion on CD4+ and CD8+ memory T cell responses generated after transplantation

Alloreactive memory T cells play a key role in transplantation by accelerating allograft rejection and preventing tolerance induction. Some studies using µMT mice, which are constitutionally devoid of B cells, showed that B cells were required for the generation of memory T cells after allotransplantation. However, whether B cell depletion in normal adult mice has the same effect on memory responses by CD4⁺ and CD8⁺ T cells activated after transplantation has not been thoroughly investigated. In this study, we tested the effect of anti‐CD20 antibody‐mediated B cell depletion on CD4⁺ and CD8⁺ memory T cell alloresponses after skin transplantation in wild‐type mice. We found that B cell depletion prevented the development of memory alloresponses by CD4⁺ T cells but enhanced that of CD8⁺ memory T cells. Next, we tested the influence of B cell depletion on hematopoietic chimerism. In OT‐II CD4⁺ anti‐OVA TCR transgenic mice sensitized to ovalbumin antigen, B cell depletion also impaired allospecific memory T cell responses and thereby enhanced donor hematopoietic chimerism and T cell deletion after bone marrow transplantation. This study underscores the complexity of the relationships between B and T cells in the generation and reactivation of different memory T cell subsets after transplantation.     

Efficient differentiation of vascular endothelial cells from dermal-derived mesenchymal stem cells induced by endothelial cell lines conditioned medium

Objective

To directionally-differentiate dermis-derived mesenchymal stem cells (DMSCs) into vascular endothelial cells (VECs) in vitro, providing an experimental basis for studies on the pathogenesis and treatment of vascular diseases.

单孔腹腔镜技术操作技巧的临床体会

目的:探讨单孔腹腔镜手术的操作技巧。方法:回顾分析2011年1月至2013年1月为189例患者行单孔腹腔镜手术的临床资料。其中单孔腹腔镜胆囊切除术160例、阑尾切除术12例、脾脏切除术7例、切口疝修补术5例、腹股沟斜疝修补术3例、胃癌根治术1例、胰十二指肠切除术1例。结果:本组中1例胆囊切除患者术中胆道损伤,予以放置支架管,一期胆道修复,余均无医源性损伤。术后胆囊切除术患者发生迟发性胆漏1例,经穿刺引流后治愈,余均无发热、腹腔积液发生,患者恢复顺利,痊愈出院。住院4¹5 d。术后随访115 d。术后随访1²3个月,无黄疸、腹部不适等症状。结论:理性的外科操作理念、精准的细节操作、扶镜手与术者的巧妙配合是保证单孔腹腔镜手术顺利进行的关键技巧。     

助理护士岗位设置对提高基础护理质量的作用

目的探讨助理护士岗位设置对基础护理质量的影响。方法采用问卷调查形式,对助理护士岗位设置前后的基础护理合格率、危重病人护理合格率、病人对基础护理质量的满意度进行对比。结果助理护士岗位设置后基础护理质量、危重病人护理质量、病人对基础护理质量的满意度明显提高,差异具有统计学意义(P<0.01或P<0.05)。结论助理护士岗位设置能有效地提高基础护理质量,培养护士的专业内涵,提高护士的整体素质,并达到合理利用人力资源的效果。     

护理专业操作技能训练方法的研究与应用

[目的]有计划对护理专业的学生进行操作技能训练，提高学生的技能操作能力及创新能力。[方法]采用比较、调查和实验等方法在两届学生中各随机抽取2个班为实验组，2个班为对照组进行研究。[结果]实验组与对照组综合实验技能成绩比较，P〈0．05，带教护士对实习生护理技能掌握情况评价比较，P〈0．01。[结论]采取规范方法进行技能操作训练，可培养学生的创新意识和解决问题的综合能力，提高护理人才质量。     

碱性成纤维生长因子在内窥镜鼻窦炎术后的临床的应用

目的:探讨碱性成纤维生长因子(bFGF)在慢性鼻窦炎术后临床效果。方法:选择78例慢性鼻窦炎行内窥镜鼻窦手术患者,随机分为治疗组39例和对照组39例,所有患者一般治疗相同,对照组术后常规以油纱条填塞鼻腔,治疗组术后使用含有bFGF的油纱条填塞鼻腔。结果:1周后出院,观察鼻腔出血、分泌物及肿胀情况,治疗组明显好于对照组,随访3个月,治疗组的治愈率较对照组的治愈率明显提高,差异有统计学意义(P<0.05)。结论:碱性成纤维细胞生长因子能安全应用于鼻内镜鼻窦手术后术腔填塞可促进鼻窦黏膜修复,提高治愈率,取得满意的临床效果。     

双能量CT的基本原理与研究进展

双能量CT（DECT）作为近几年影像学领域比较热门的一个研究方向,弥补了常规CT在疾病诊断中的部分不足,为疾病诊断、分期及治疗提供了更多影像学依据。本文概述DECT的基本原理、实现途径及近期研究进展,介绍DECT在临床应用中存在的不足,并展望其未来的发展方向。     

护士临床操作技能的培训方法与效果

目的探讨适合临床护士的操作技能培训方法。方法每个操作项目都经过示范、提出问题、临床辅导与问题探讨、病房现场考核4个环节。考核内容包括10个方面:护士着装仪表、对病人的解释、对病情的评估、用物准备、操作步骤、应变能力、用物与废弃物的处理、与病人的交流与沟通、相关知识问答和异常情况处理能力。结果对解剖相关知识回答正确率、操作中异常情况的正确处理率、病情评估正确率、与病人沟通和解释合理性、临床应变能力等方面,两组护士差异均具有统计学意义(P<0.05)。结论结合临床实践对护士进行技能培训,能有效提高护士的临床应变能力、解决问题能力和相关知识水平。