快速成型骨组织工程支架的结构及力学仿生性能特征

目的:利用显微CT的成像技术及材料力学测试,观察多孔双相磷酸钙陶瓷支架的三维结构和力学仿生性能特征。方法:实验于2004-06/2005-12在清华大学新型陶瓷与精细工艺国家重点实验室、香港中文大学威尔士亲王医院骨与关节肌肉研究室和解放军总医院骨科研究所完成。利用三维凝胶叠层成型技术和发泡法复合的方法,制备仿骨多孔双相磷酸钙陶瓷支架,经显微CT扫描得到分辨率为20μm的断层图像,并按骨形态计量方法计算三维计量参数,并与急性脑死亡年轻人股骨头(由解放军总医院骨组织库提供,已签署捐献同意书)标本负重区松质骨样本的三维参数进行统计比较。最后对双相磷酸钙陶瓷支架两个互相垂直方向和松质骨样本的长轴方向进行压缩强度试验,计算压缩强度和弹性模量,并进行统计分析。结果:①双相磷酸钙陶瓷支架的小梁平均宽度和间距低于松质骨小梁(P<0.05);支架的小梁数目和各项异性程度高于松质骨样本(P<0.05);说明支架小梁在排列上呈现更为明显的各向异性特征。②双相磷酸钙陶瓷支架的体积分数、表面积体积比及结构模型指数与松质骨样本相比差异无显著性(P>0.05),两组样本均呈明显的板层结构。③力学测试结果显示双相磷酸钙陶瓷支架材料长轴方向的强度和弹性模量高于垂直方向(P<0.05),说明支架材料具有明显的方向性。长轴方向的强度低于正常松质骨样本,但弹性模量仅比松质骨样本弹性模量高20%(P<0.05)。结论:支架材料在空隙率和表面积方面具有很好的仿生性,利于细胞的黏附和长入。同时具有明显的方向性,提高了其在排列方向上的强度。弹性模量接近股骨头松质骨,具有较好的应力顺应性。     

Cytometric characterization of the cell nucleus and nucleolus apparatus in dysplasia and exocervical cancer of the cervix uteri

The morphometric parameters of the nucleonucleolar apparatus of the intact stratified squamous epithelium of the cervix uteri, dysplasias, and exocervical cancer were studied by computed morphometry of 50% silver nitrate solution-stained cytological specimens in order to study nucleolar organizers. It was shown that dysplastic changes and malignant transformation were marked by a progressive increase in the values of morphometric parameters of its nucleonucleolar apparatus. The staining of nucleolar organizers is relatively simple and it is expedient to use it for a specifying cytological diagnosis. The advantage of the staining is to identify rare atypical cells in cytological specimens.     

Surgery in patients with haemophilia and high responding inhibitors: Izmir experience

Summary. This report evaluates the haemostatic efficacy of recombinant factor VIIa (rFVIIa) and activated prothrombin complex concentrate (APCC) in patients with haemophilia and high responding inhibitors who underwent major and minor surgery. Data pertaining to surgeries from 2001 to 2009 at a single centre were retrospectively analysed. During this period, 53 surgical procedures were performed in 30 haemophiliacs with high responding inhibitors. Mean age was 16.2 ± 9.4 years. Eleven major surgeries in 4 patients, 41 radioisotope synovectomies (RS) and one circumcision classified as minor surgery in 28 patients were performed. Among the major surgery procedures, four were treated with rFVIIa, five with APCC and two with sequential use of APCC and rFVIIa. We used rFVIIa at the dosage of 80–120 μg kg^?1 every 2 h and APCC 100 IU kg^?1 every 12 h for the major surgery. When performing RS, we used rFVIIa in 18 patients with 26 target joints and APCC in 9 patients with 15 target joints. Three consecutive doses of rFVIIa (90 μg kg^?1) were used at 2‐h intervals followed by additional three doses at 6‐h intervals. The initial dose of APCC was 75 IU kg^?1 followed by a second and third dose of 50 IU kg^?1 at 12‐h intervals. APCC and rFVIIa demonstrated excellent efficacy in our major and minor surgical interventions [100% (22/22) and 94% (31/33), respectively]. We had only two bleeding complications with rFVIIa. There were no thromboembolic complications. APCC and rFVIIa provide an effective and safe first line haemostatic therapy for inhibitor‐positive haemophiliacs, allowing both major and minor surgery to be successfully performed.     

Patient resources in the therapeutic education of haemophiliacs in France: their skills and roles as defined by consensus of a working group

Summary. The activities of ‘expert patients’ or ‘patient tutors’, who help educate their peers, are gaining recognition in the health care system. This study investigates the role played by such patients in therapeutic education programmes organized by caregivers to validate the role of patients in implementing the therapeutic education of haemophilic patients and to define the skills required for such activities. This study employs the consensus methodology recommended by France’s National Authority for Health. The working group includes seven caregivers from Hemophiliac Treatment Centers (HTCs) and three patients from the French Association of Hemophiliacs (FAH). The role of patients in haemophilia education is recognized. Patients participating in the education of their peers are referred to as ‘patient resources’. A patient resource should be an adult, a volunteer and live in the same region as his peers. Candidates are chosen by the FAH and the HTCs to serve based on their motivation to facilitate the education of other patients as well as on their psychological and pedagogical aptitudes. A patient resource participates in the conception and administration of therapeutic education programmes. He also mediates between the caregivers and the patients. He ensures that the patients understand the material and are able to apply their knowledge in daily life. His activities are governed by professional ethics. Seven categories of skills were defined, permitting the group to determine precisely which skills are required to function as a patient resource. Supervision of the patients is planned to reinforce reflexive practices in the patients. Evolution of the health care system has led patients to become involved in therapeutic education. This phenomenon calls for a framework to be developed and an evaluation of its eventual effects.     

StpC-based gene therapy targeting latent reservoirs of HIV-1

The ability of HIV-1 to form latent reservoirs presents a major obstacle to eradication. One approach to elimination of the latent reservoir is induction therapy, whereby cells harboring latent virus are activated and therefore initiate virus replication. We have constructed a lentiviral vector encoding Herpesvirus saimiri subgroup C saimiri transformation-associated protein (StpC), which has been shown to modulate HIV-1 replication, under the control of a cytomegalovirus promoter in order to determine the ability of StpC to upregulate latent HIV-1. We have included a suicide gene, herpes simplex virus thymidine kinase (TK), under the control of the HIV-1 long terminal repeat (LTR) promoter. We hypothesized that upon StpC expression in latently infected cells induction of virus replication and subsequent production of viral transactivators of the LTR will activate expression of the tk gene, sensitizing the cells to the nucleoside analogue ganciclovir (GCV). Transduction of the latently infected cell line J1.1 resulted in increased virus replication. In the presence of GCV transduced cells exhibited decreased HIV-1 replication, inhibition of cell proliferation, and increased apoptosis. This prototype vector serves as a proof of concept of the utility of gene-based induction agents and suicide genes as a new method for targeting reservoirs of latent HIV-1.     

Rapid ubiquitination of Syk following GPVI activation in platelets

Spleen tyrosine kinase (Syk) activation is a key intermediate step in the activation of platelets by the physiologic agonist collagen. We have found that Syk is rapidly ubiquitinated upon activation of platelets by collagen, collagen-related peptide (CRP), and convulxin. The Src family kinase inhibitors prevented Syk phosphorylation and its ubiquitination, indicating that the process is downstream of Src kinases. The ubiquitination of Syk did not cause degradation of the protein as evidenced by the lack of effect of proteasomal and lysosomal inhibitors. We separated ubiquitinated Syk from its nonubiquitinated counterpart and used an in vitro kinase assay to compare their activities. We found that the ubiquitinated Syk appeared to be about 5-fold more active. Using a phosphospecific antibody to Syk (Tyr525/Tyr526) that measures activated Syk, we found that most (60%-75%) of the active Syk is in the ubiquitinated fraction. This result explains the apparent high specific activity of ubiquitinated Syk. In c-Cbl-deficient mice, Syk is not ubiquitinated, implicating c-Cbl as the E3 ligase involved in Syk ubiquitination. Furthermore, Syk is not dephosphorylated in these mice. We propose that c-Cbl plays a regulatory role in glycoprotein VI (GPVI)/Fc receptor gamma (FcRgamma)-chain-dependent platelet activation through its interaction with Syk.