Particulate endocytosis mediates biological responses of human mesenchymal stem cells to titanium wear debris.

Continual loading and articulation cycles undergone by metallic (e.g., titanium) alloy arthroplasty prostheses lead to liberation of a large number of metallic debris particulates, which have long been implicated as a primary cause of periprosthetic osteolysis and postarthroplasty aseptic implant loosening. Long-term stability of total joint replacement prostheses relies on proper integration between implant biomaterial and osseous tissue, and factors that interfere with this integration are likely to cause osteolysis. Because multipotent mesenchymal stem cells (MSCs) located adjacent to the implant have an osteoprogenitor function and are critical contributors to osseous tissue integrity, when their functions or activities are compromised, osteolysis will most likely occur. To date, it is not certain or sufficiently confirmed whether MSCs endocytose titanium particles, and if so, whether particulate endocytosis has any effect on cellular responses to wear debris. This study seeks to clarify the phenomenon of titanium endocytosis by human MSCs (hMSCs), and investigates the influence of endocytosis on their activities. hMSCs incubated with commercially pure titanium particles exhibited internalized particles, as observed by scanning electron microscopy and confocal laser scanning microscopy, with time-dependent reduction in the number of extracellular particles. Particulate endocytosis was associated with reduced rates of cellular proliferation and cell-substrate adhesion, suppressed osteogenic differentiation, and increased rate of apoptosis. These cellular effects of exposure to titanium particles were reduced when endocytosis was inhibited by treatment with cytochalasin D, and no significant effect was seen when hMSCs were treated only with conditioned medium obtained from particulate-treated cells. These findings strongly suggest that the biological responses of hMSCs to wear debris are triggered primarily by the direct endocytosis of titanium particulates, and not mediated by secreted soluble factors. In this manner, therapeutical approaches that suppress particle endocytosis could reduce the bioreactivity of hMSCs to particulates, and enhance long-term orthopedic implant prognosis by minimizing wear-debris periprosthethic osteolysis.     

Pulmonary Lophomonas blattarum infection in patients with kidney allograft transplantation

The aim of the study was to analyse the clinical manifestation and management of pulmonary Lophomonas blattarum infection in four allograft transplantation recipients retrospectively. Four patients with pulmonary L. blattarum infection were diagnosed by using Fiberoptic bronchoscopy (FOB) and bronchoalveolar lavage (BAL) examination. Their clinical manifestation and management are summarized. Four cases of pulmonary L. blattarum were found during the period from the second month to the third month after transplantation. Concurring infection by other pathogens was found in three of them. Common initial symptoms included fever (>38 degrees C) without cough and breathlessness. Lower lobe shadowing could be found on chest X-ray. Body temperature decreased to the normal range in three patients and to 37.5 degrees C in the other one, after intravenous injection of metronidazole and tapering immunosuppressant. Radiological examination confirmed improved health condition of the patients afterwards. Two patients received repeated FOB and only dead L. blattarum was found. Pulmonary L. blattarum infection in allograft transplant recipients carry relatively obscure initial symptoms. Possible L. blattarum infection needs to be screened in post-transplantation pulmonary infection patients with similar symptoms, especially in those who respond poorly to anti-infection treatment. Microscopic examination of BAL fluid can help to identify pulmonary L. blattarum infection and metronidazole is an ideal treatment choice.     

Humoral and Cellular Responses to Influenza Vaccination in Human Recipients Naturally Tolerant to a Kidney Allograft

Rare kidney allograft recipients enjoy unaltered graft function years after interruption of their immunosuppressive treatment. To assess the extent to which this state of 'operational tolerance' (TOL) is specific to the graft and not the result of a global immunodeficiency, we analyzed the response of such patients following influenza vaccination. Hemagglutination inhibition titers and frequency of IFNgamma-secreting T cells were measured before 1 and 3 months after vaccination. The proportion of healthy volunteers (HV) responding to vaccine was significantly higher than that of immunosuppressed (IS) patients. Three 'TOL' patients presented a humoral response similar to that of HV, whereas the two others had a poor response, like the IS recipients. Although the small number of patients does not allow for definitive conclusions to be made, these data suggest that the status of tolerance may be heterogeneous, with some patients with a global immunodeficiency and others with an adapted response to vaccination.     

塞来昔布对大鼠心脏移植急性排斥反应的抑制作用

目的观察塞来昔布对大鼠心脏移植急性排斥反应的抑制作用。方法以SD大鼠为供者,Wistar大鼠为受者,进行40次腹部异位心脏移植。采用HE染色和原位末端标记(TUN EL)技术检测移植心切片,进行排斥反应的病理分级并计算移植心肌细胞的凋亡指数(AI)。结果移植心的细胞凋亡主要发生于心肌细胞;移植后第3、5d,塞来昔布治疗组心肌细胞凋亡指数分别为:1.03±0.42和3.28±2.42;对照组分别为2.35±1.51和11.35±3.46;两组比较,差异有统计学意义(P<0.001)。结论细胞凋亡是心脏移植急性排斥中组织损伤的重要机制;塞来昔布能明显抑制心肌细胞凋亡。     

Survivin在食管癌中的表达及其与bcl-2表达关系的相关研究

目的探讨Survivin在食管癌组织中的表达及其与bcl-2蛋白表达的相关性。方法应用免疫组织化学SP法,检测Survivin、bcl-2蛋白在68例食管癌组织和20例正常食管组织中的表达。结果Survivin蛋白在正常食管组织中低表达或不表达,68例食管癌组织中,49例表达阳性,占72.1%。Survivin蛋白表达与分化程度、淋巴结转移密切相关(P<0.05)。食管癌组织bcl-2蛋白表达阳性、阴性组中,Survivin蛋白阳性表达率分别为94.7%(36/38)和43.3%(13/30),两者比较,差异有统计学意义(P<0.05)。Survivin蛋白表达与bcl-2蛋白表达密切相关。结论Survivin在食管癌组织中表达上调,通过抑制细胞凋亡,在食管癌的发生中起到重要作用;凋亡相关基因bcl-2的上调与Survivin的表达可能在食管癌变中起协同作用。     

PTEN及Bcl-2蛋白在膀胱移行细胞癌中的表达及其意义

目的：探讨PTEN及Bcl-2蛋白在膀胱移行细胞癌的表达规律及其临床意义。方法：应用免疫组织化学链亲和素-生物素-霉复合物（SP）方法检测43例膀胱移行细胞癌和7例正常黏膜组织中PTEN及Bcl-2蛋白的表达．分析二者的表达与膀胱癌病理参数的关系。结果：（1）G1、G2、G3肿瘤PTEN表达阳性率分别为85．7％、80．4％、73．3％，浸润性肿瘤和表浅性肿瘤表达阳性率分别为70．4％和93．8％，说明PTEN表达阳性率与肿瘤病理分级、临床分期有关。（2）G。、G2、G3肿瘤Bcl-2表达阳性率分别为14．2％、57．14％、66．67％，浸润性肿瘤和表浅性肿瘤表达阳性率分别为59．3％和43．8％，说明Bcl-2表达阳性率与肿瘤病理分级、临床分期有关。（3）随着肿瘤恶性程度的增高和临床分期进展，PTEN蛋白阳性率呈下降，Bcl-2表达呈增高趋势，二者表达呈负相关关系。结论：PTEN的抑癌作用可能与Bcl-2有关．二者的异常表达在膀胱移行细胞癌的发生、发展过程中起重要作用。二者同时检测有助于判断预后。     

Coccidioidomycosis After Renal Transplantation in an Endemic Area

Coccidioidomycosis is an endemic fungal infection of the desert southwestern United States of particular concern for immunosuppressed renal transplant recipients. The clinical course of coccidioidomycosis can be severe in immunosuppressed patients, with high rates of dissemination and mortality, and antifungal prophylaxis is routinely administered to high-risk patients. We sought to determine the impact of coccidioidomycosis on patients who received their renal transplant at our hospital in Phoenix, Arizona. A retrospective records review of the first 205 patients who received a renal transplant between June 1999 and December 2003 identified 6 patients (3%) who had contracted coccidioidomycosis after transplantation. All six cases occurred more than 6 months after transplantation. Two of these six patients had disseminated coccidioidomycosis. Two patients, one with pulmonary infection and one with disseminated infection, died. None of the six patients with coccidioidomycosis after transplantation had identified risk factors before transplantation. No high-risk patient who received targeted antifungal prophylaxis had a reactivation of coccidioidomycosis after transplantation. Treatment for acute rejection and induction with antithymocyte globulin did not appear to increase the risk of subsequent coccidioidomycosis.     

肾移植术后并发尿路上皮肿瘤的临床分析

目的 分析肾移植患者并发尿路上皮肿瘤的特点，探讨其诊治方法。方法 自1998～2003年肾移植患者1293例，术后发生尿路上皮恶性肿瘤21例（1．6％）。男4例，女17例。17例原发病为慢性问质性肾炎。发生尿路上皮肿瘤距肾移植6～62个月，平均26个月。其中膀胱癌6例，单侧肾盂或输尿管癌6例，单侧肾盂或输尿管、膀胱癌8例，双侧肾盂输尿管癌1例。10例上尿路肿瘤发生部位与移植肾同侧，4例发生于移植肾对侧。临床症状以无痛性肉服血尿和反复泌尿系感染为主。19例行手术治疗，术后所有患者免疫抑制剂用量减少1／3并辅以局部灌注化疗。结果 2例行姑息性治疗的晚期肿瘤患者分别于发现肿瘤5、8个月死亡。余19例现已随访2～5年。13例肿瘤复发，复发部位为膀胱或对侧原。肾、输尿管。所有患者在免疫抑制剂减量期间均未出现急性排斥。2例因切除移植肾恢复透析，17例肾功能正常。结论 慢性间质性。肾炎导致。肾功能衰竭的。肾移植患者和女性肾移植患者易发生移植后尿路上皮肿瘤；移植肾同侧上尿路较对侧好发肿瘤；对移植肾对侧为首发的上尿路发生肿瘤者可预防性行双侧上尿路根治性切除。