自主研制镍钛记忆合金左心耳封堵器封闭左心耳对实验动物左心功能的影响

目的:应用经胸彩色多普勒超声技术评价自主研制的镍钛记忆合金左心耳封堵器封闭左心耳对实验动物猪左心房、左心室功能的影响。方法:实验于2005-09/2006-08在南京医科大学第一附属医院江苏省实验动物中心完成。①实验分组:选用苏钟小型种猪17只,随机分为实验组12只和对照组5只。②实验干预:实验组12只苏钟小型种猪使用自主研制的左心耳封堵器(发明专利号码:200610037789.3,公开号CN1799521,由镍钛合金骨架、多聚四氟乙烯膜和传送连接部分等构成。其外观呈单盘状,封堵器的左心房面呈圆盘状,直接连接放入心耳内的圆柱体结构)行左心耳封堵,对照组5只手术步骤相同而不采用封堵器行左心耳封堵。③实验评估:两组动物分别于术前、术后1周、2周、4周采用经胸超声心动图检查观察心功能的改变,测量左心房内径、最大及最小容积、左房射血分数、左心房搏出量、血流分数等左房功能参数以及左室射血分数、左室短轴缩短率、Tei指数、E/A比值等指标。结果:①实验动物数量分析:在施行左心耳封堵后,1头猪于术中出血过多并出现室颤后死亡,1头猪因封堵器脱入左房,卡在二尖瓣口导致死亡。其余动物封堵效果良好。②两组动物术后1,2,4周左房功能指标各参数与术前比较无明显变化(P>0.05);与术前相比,实验组术后1周、2周左室射血分数、左心室短轴缩短率、E/A比值分别由术前的0.70±0.04、0.39±0.03、1.33±0.28降低至术后1周的0.59±0.05、0.31±0.03、0.95±0.11(P<均0.01)及术后2周的0.62±0.05、0.33±0.05、0.90±0.05(P<均0.01);Tei指数由术前的0.48±0.02增加至术后1周的0.59±0.03(P<0.01)及术后2周的0.58±0.04(P<0.01)。对照组手术前后左室功能指标差异无显著性。结论:自主研制左心耳封堵器可以有效的封堵左心耳;左心耳封堵后短期内对实验动物左房功能无明显影响;封堵后短期内对左心室功能具有短期的减弱,更长期的安全性有待于进一步研究。     

Donation reactions among autologous donors

Studies of risk factors associated with reactions among autologous blood donors have been limited. Therefore, 2091 autologous and 4737 homologous donations were examined. Donors at greatest risk for reaction were autologous donors who had reactions at first donation; among 45 who made repeat donations for the same surgery, 17 (38%) had repeat reactions. The group least likely to experience reactions were the autologous donors greater than or equal to 66 years old; they experienced a 1.9 greater than or equal to percent (6/310) incidence of reactions. More reactions were seen in both autologous and homologous donors in the categories of first-time donor, female gender, decreasing age, and lower weight. Multiple logistic regression analysis showed that all of these variables were independent predictors of donor reaction, with first-time donation (odds ratio, 2.4) and female gender (odds ratio, 1.9) being the strongest predictors of reaction. Donor room personnel should be alerted that autologous donors who react at first donation are very likely to react at subsequent donations. Contrary to common concern, elderly autologous donors are least likely to have reactions.     

人工髓核假体置入治疗腰椎间盘突出症的疗效分析

目的：观察已在临床初步开展起来的人工髓核置换术治疗腰椎间盘突出症的中、远期临床疗效及并发症,分析其对策。 方法：纳入2002-02/2004-08南方医科大学附属南方医院脊柱骨病外科采用单枚人工髓核假体置换术治疗单节段腰椎间盘突出症患者98例,获得24～48个月随访患者75例,按平均随访时间达24,36,48个月,分为24个月组（n=30）,36个月组（n=23）,48个月组（n=22）。选同期采用单纯椎间盘髓核摘除术患者30例作为对照组,评估各组术后临床疗效,主观症状采用Oswestry功能障碍指数问卷表（0%表示正常,越接近100%则功能障碍越严重）和Prolo功能评分表（小于或等于5分为差,6～7分为中等,8～10为优）评价,分析术后影像学检查并测量手术节段活动度和椎间隙高度变化情况,同时观察假体位置情况,腰椎MRI观察假体位置和软骨终板的信号变化情况。腰椎活动度=（腰椎中立角度-前屈角度）＋（后伸角度-腰椎中立角度）=后伸角度-前屈角度;为消除X射线放大率的影响,椎间隙高度变化情况采用病变椎间隙后缘高度与上位椎体中部矢状径的比值表示。 结果：75例获得24～48个月随访者,全部进入结果分析。①48个月组2例、36个月组1例发生假体脱出,二次手术取出。其余患者术后临床症状均明显缓解,疼痛消失。②24,36,48个月组及对照组术后末次Oswestry功能障碍指数均较术前降低,差异有显著性意义（14.2%,52.1%;15.5%,55.2%;15.1%,53.6%;15.5%,51.5%;P〈0.05）。③24,36,48个月组及对照组术后末次Prolo能评分均较术前升高,差异有显著性意义（8.5,4.6分;8.6,4.5分;8.7,4.3分;8.4,4.2分;P〈0.05）。④24,36,48个月组同期手术节段腰椎活动度均高于对照组,差异有显著意义（P〈0.05）。⑤24个月组手术节段椎间高度较术前降低约4%、36个月组降低约12%、48个月组降低约18%、对照组较术前降低约25%,各组术前和术后椎间隙高度比值比较,差异具有显著性意义（P〈0.05）。⑥主要并发症：早期出现术后一过性腰痛24例,假体脱出3例。中、远期发现假体下沉32例,软骨终板损伤39例。 结论：单枚人工髓核假体置换治疗腰椎间盘突出症中、远期随访临床疗效肯定,但存在较严重并发症,应慎重开展此项手术。     

Interaction of single-chain urokinase with its receptor induces the appearance and disappearance of binding epitopes within the resultant complex for other cell surface proteins

Binding of urokinase-type plasminogen activator (uPA) to its glycosylphosphatidylinositol-anchored receptor (uPAR) initiates signal transduction, adhesion, and migration in certain cell types. To determine whether some of these activities may be mediated by associations between the uPA/uPAR complex and other cell surface proteins, we studied the binding of complexes composed of recombinant, soluble uPA receptor (suPAR) and single chain uPA (scuPA) to a cell line (LM-TK- fibroblasts) that does not express glycosylphosphatidylinositol (GPI)-anchored proteins to eliminate potential competition by endogenous uPA receptors. scuPA induced the binding of suPAR to LM-TK- cells. Binding of labeled suPAR/scuPA was inhibited by unlabeled complex, but not by scuPA or suPAR added separately, indicating cellular binding sites had been formed that are not present in either component. Binding of the complex was inhibited by low molecular weight uPA (LMW-uPA) indicating exposure of an epitope found normally in the isolated B chain of two chain uPA (tcuPA), but hidden in soluble scuPA. Binding of LMW-uPA was independent of its catalytic site and was associated with retention of its enzymatic activity. Additional cell binding epitopes were generated within suPAR itself by the aminoterminal fragment of scuPA, which itself does not bind to LM-TK- cells. When scuPA bound to suPAR, a binding site for alpha 2-macroglobulin receptor/LDL receptor-related protein (alpha 2 MR/LRP) was lost, while binding sites for cell-associated vitronectin and thrombospondin were induced. In accord with this, the internalization and degradation of cell-associated tcuPA and tcuPA-PAI- 1 complexes proceeded less efficiently in the presence of suPAR. Further, little degradation of suPAR was detected, suggesting that cell- bound complex dissociated during the initial stages of endocytosis. Thus, the interaction of scuPA with its receptor causes multiple functional changes within the complex including the dis-appearance of an epitope in scuPA involved in its clearance from the cell surface and the generation of novel epitopes that promote its binding to proteins involved in cell adhesion and signal transduction.     

The impact of late acute rejection after cadaveric kidney transplantation

BACKGROUND: Acute graft rejection (AR) following renal transplantation results in reduced graft survival. However, there is uncertainty regarding the definition, aetiology and long-term graft and patient outcome of AR occurring late in the post-transplant period. AIM: To determine if rejection episodes can be classified by time from transplantation by their impact on graft survival into early acute rejection (EAR) and late acute rejection (LAR). MATERIALS AND METHODS: 687 consecutive adult renal transplant recipients who received their first cadaveric renal transplant at a single centre. All received cyclosporine (CyA)-based immunosuppression, from 1984 to 1996, with a median follow-up of 6.9 yr. Details were abstracted from clinical records, with emphasis on age, sex, co-morbid conditions, HLA matching, rejection episodes, patient and graft survival. ANALYSIS: Patients were classified by the presence and time to AR from the date of transplantation. Using those patients who had no AR (NAR) as a baseline, we determined the relative risk of graft failure by time to rejection. The characteristics of patients who had no rejection, EAR and LAR were compared. RESULTS: Compared with NAR, the risk of graft failure was higher for those patients who suffered a rejection episode. A much higher risk of graft failure was seen when the first rejection episode occurred after 90 d. Thus, a period of 90 d was taken to separate EAR and LAR (relative risk of 3.06 and 5.27 compared with NAR as baseline, p<0.001). Seventy-eight patients (11.4%) had LAR, 271 (39.4%) had EAR and 338 (49.2%) had NAR. The mean age for each of these groups differed (LAR 39.6 yr, EAR 40.8 yr compared with NAR 44 yr, p<0.003). The 5-yr graft survival for those who had LAR was 45% and 10-yr survival was 28%. HLA mismatches were more frequent in those with EAR vs. NAR (zero mismatches in HLA-A: 36 vs. 24%, HLA-B: 35 vs. 23% and HLA-DR: 63 vs. 41%, p<0.003). There was no difference in mismatching frequency between NAR and LAR. CONCLUSIONS: AR had a deleterious impact on graft survival, particularly if occurring after 90 d. AR episodes should therefore be divided into early and late phases. In view of the very poor graft survival associated with LAR, it is important to gain further insight into the main aetiological factors. Those such as suboptimal CyA blood levels and non-compliance with medication should be further investigated with the aim of developing more effective immunosuppressive regimens in order to reduce the incidence of LAR.     

The role of leptin in human growth and puberty

Experimental animal studies demonstrate the effects of leptin on appetite, weight gain and metabolism. The biological effects of leptin in human adults are still to be determined, but recent reports show that congenital leptin deficiency leads to hyperphagia and excessive weight gain from early infancy as well as failure of pubertal onset in adolescence. Our recently reported data from two longitudinal cohorts suggest a role for leptin in the normal regulation of childhood weight gain, maturation and the development of secondary sexual features and body composition. Low leptin levels in cord blood closely reflected decreased adiposity at birth and stringly predicted high rates of weight gain in infancy and cath-up growth. In adolescents, leptin levels rose gradually with age prior to puberty, suggesting that a threshold effect may trigger puberty. In girls, low leptin levels at the start of puberty predicted large gains in the percentage of fat mass, perhaps suggesting a role in the preparation for childbearing.     

The cerebellopontine angle and internal auditory canal: neurovascular anatomy on gas CT cisternograms

We reviewed 103 normal gas CT cisternograms to delineate the appearance of normal neurovascular structures in the cerebellopontine angle (CPA) and internal auditory canal (IAC). Cranial nerves VII and VIII were identified in the CPA in 97% of cases, either separately (53%) or as a bundle (44%). Intracanalicular branches of the VIIIth cranial nerve were identified in 20% of cases, and cranial nerve V was visualized in the CPA in 14%. The characteristic vascular loop, usually the anterior inferior cerebellar artery, was visible in 35% of cases, and, in 22% of visualized cases, was in an intracanalicular location. The internal auditory artery was questionably visualized in one case. In 10% of cases, greater than 66% of the IAC was occupied by the neurovascular bundle. Familiarity with the normal anatomy and variants seen on gas CT cisternograms is necessary to prevent false-positive interpretations.