Substrate geometry directs the in vitro mineralization of calcium phosphate ceramics

Repetitive concavities on the surface of bone implants have recently been demonstrated to foster bone formation when implanted at ectopic locations in vivo. The current study aimed to evaluate the effect of surface concavities on the surface mineralization of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) ceramics in vitro. Hemispherical concavities with different diameters were prepared at the surface of HA and β-TCP sintered disks: 1.8 mm (large concavity), 0.8 mm (medium concavity) and 0.4 mm (small concavity). HA and β-TCP disks were sintered at 1100 or 1200 °C and soaked in simulated body fluid for 28 days at 37 °C; the mineralization process was followed by scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction and calcium quantification analyses. The results showed that massive mineralization occurred exclusively at the surface of HA disks treated at 1200 °C and that nucleation of large aggregates of calcium phosphate started specifically inside small concavities instead of on the planar surface of the disks. Regarding the effect of concavity diameter size on surface mineralization, it was observed that small concavities induce 124- and 10-fold increased mineralization compared to concavities of large or medium size, respectively. The results of this study demonstrated that (i) in vitro surface mineralization of calcium phosphate ceramics with surface concavities starts preferentially within the concavities and not on the planar surface, and (ii) concavity size is an effective parameter to control the spatial position and extent of mineralization in vitro.     

A novel injectable,cohesive and toughened Si-HPMC (silanized-hydroxypropyl methylcellulose) composite calcium phosphate cement for bone substitution

This study reports on the incorporation of the self-setting polysaccharide derivative hydrogel (silanized-hydroxypropyl methylcellulose, Si-HPMC) into the formulation of calcium phosphate cements (CPCs) to develop a novel injectable material for bone substitution. The effects of Si-HPMC on the handling properties (injectability, cohesion and setting time) and mechanical properties (Young’s modulus, fracture toughness, flexural and compressive strength) of CPCs were systematically studied. It was found that Si-HPMC could endow composite CPC pastes with an appealing rheological behavior at the early stage of setting, promoting its application in open bone cavities. Moreover, Si-HPMC gave the composite CPC good injectability and cohesion, and reduced the setting time. Si-HPMC increased the porosity of CPCs after hardening, especially the macroporosity as a result of entrapped air bubbles; however, it improved, rather than compromised, the mechanical properties of composite CPCs, which demonstrates a strong toughening and strengthening effect. In view of the above, the Si-HPMC composite CPC may be particularly promising as bone substitute material for clinic application.     

The effect of chemical potential on the thermodynamic stability of carbonate ions in hydroxyapatite

First-principles calculations were performed for CO₃²⁻ ions in hydroxyapatite in order to investigate the atomic structures and thermodynamic stability of CO₃²⁻ and its related defects. Two different chemical equilibrium conditions in high-temperature and aqueous-solution environments were considered, and atomic and ionic chemical potentials for the individual chemical equilibrium conditions were evaluated to calculate defect formation energies. It was found that A-type CO₃²⁻ (substituting OH⁻) is energetically more favorable than B-type CO₃²⁻ (substituting PO₄³⁻) in the high-temperature environment, whereas B-type is preferred to A-type in the aqueous solution environment. This result successfully reproduces experimentally observed trends. In the formation of A-type and B-type CO₃²⁻, OH⁻ vacancies or protons (interstitial or substitutional) act as charge-compensating defects.     

Cytologic evaluation of lymphoproliferative lesions of the orbit/ocular adnexa: An analysis of 46 cases

The cytologic features of 46 lymphoproliferative ophthalmic lesions were evaluated using the “squash” technique and/or touch imprints at the time of frozen section. Of the 46 lesions, 33 were located in the orbit, 12 in the conjunctiva, and one in the eyelid. Fifteen cases were benign (reactive) hyperplasias, and 31 were diagnosed as malignant lymphoproliferative tumors. The cytologic features of the reactive group included a polymorphic lymphoid population intermixed with scattered tingible body macrophages. Within the malignant category, there were 28 malignant lymphomas. All 28 cases were diagnosed as non-Hodgkin's lymphomas. Cytologically, the malignant group consisted of a monomorphic population of atypical lymphoid cells. Of the 31 malignant lymphoid lesions, 58% (18 tumors) were small lymphocytic proliferations. The remaining 13 tumors were classified as follows: mixed small/large cell or pure large cell lymphomas (nine), plasmacytoma (three), and Burkitt's lymphoma (one). Final classification using the Working Formulation was made after evaluating the cytologic preparations and surgical material. In selected cases, the monoclonal nature of the malignant lymphoproliferative lesions was confirmed by flow cytometry and/or immunocytochemistry. Cytologic preparations of the fresh specimens preserve the morphologic details of the tumor cells, which is especially important when evaluating lymphoid lesions. Additionally, multiple smears can be prepared simultaneously for ancillary studies such as immunocytochemistry. Of our 46 lymphoproliferative lesions, two-thirds were diagnosed as malignant lymphomas. Based on the morphologic and immunophenotypic findings, all the malignant lymphomas were B-cell tumors, 50% of which were low grade using the Working Formulation. Diagn Cytopathol 1996;15:241–245 © 1996 Wiley-Liss, Inc.     

离体眼眶肿瘤及正常组织超高场磁共振波谱特点的比较

目的:运用超高场MR系统对离体眼眶肿瘤及正常组织进行体外MRS检测,观察眼眶不同病变类型在超高场磁共振条件下的波谱特点,为MRS波谱分析的临床应用提供理论依据.方法:临床肿瘤标本10例,良性肿瘤7例,恶性肿瘤3例,正常组织标本2例,采用BRUKER AVANCE 400(SB)超高场核磁共振谱仪进行检测,比较各自不同的波谱特点.结果:1H-MRS波谱分析结果表明:从波峰测量和形态上看,眼眶恶性肿瘤Cho和Cr峰值要高于良性肿瘤;良、恶性眼眶肿瘤组织波谱分析在2.0×10-6附近可见到3个连续的单峰,而正常组织均无此波谱现象.结论:1H-MRS 波谱分析能够区分离体眼眶良、恶性肿瘤及正常组织,值得进一步探讨以应用于临床.     

Malleostapedotomy for otosclerosis,our experience of nitinol piston on twelve patients

ObjectiveMalleostapedotomy allows to completely by-pass the incus in otosclerosis surgery. Recently its use has been rivaled by hydroxyapatite cement for cases of mild and moderate necrosis of the incus. However, it remains gold standard for cases of extensive necrosis, incus dislocation, or epitympanic fixation. Modern heat-crimping pistons make surgery easier and safer. This study focuses on our experience with this technique.MethodsRetrospective analysis of patient’s files and pre- and post-operative audiograms, for cases of surgically treated otosclerosis with malleostapedotomy.ResultsTwelve patients underwent malleostapedotomy for otosclerosis between 2011 and 2019. Amongst them there were 10 revision surgeries and 2 primary cases. 75% had incus long-process necrosis, 17% had epitympanic fixation and one had a history of incus transposition. Nine patients (75%) had closure of air-bone gap (ABG) of <10 dB (p < 0.001) and 11 (92%) had a threshold of 20 dB (p < 0.001). Mean pre-operative ABG was 31 dB (15 dB–55 dB), and mean post-operative ABG was 7 dB (0 dB–21 dB; p < 0.001). There was no sensorineural hearing loss nor any other post-operative complication.ConclusionsMalleostapedotomy is a safe and reliable technique, allowing an ABG closure comparable to conventional incus to vestibule prosthesis. It remains the preferred technique whenever the incus cannot be used.     

对映异构聚乳酸/聚乙二醇空间异构复合水凝胶的药物释放及形貌和细胞毒性

背景：目前生物降解水凝胶已被广泛应用于抗癌药物及生物活性大分子的装载,但为了保护生物活性大分子的活性,需要得到凝胶化条件更温和,凝胶化时间更短的凝胶体系。 目的：制备对映异构聚乳酸∕聚乙二醇的空间异构复合水凝胶,使其具有更短的凝胶化时间,实现对模拟药物溶菌酶的装载和控释。 方法：以聚乙二醇为引发剂,辛酸亚锡为催化剂,丙交酯与聚乙二醇发生开环聚合反应,得到聚乳酸/聚乙二醇的三嵌段共聚物(PLLA-PEG-PLLA 和 PDLA-PEG-PDLA)。用1H NMR,FT-IR 和 XRD表征三嵌段共聚物。10% PLLA20-PEG227-PLLA20的水溶液和10%PDLA21-PEG227-PDLA21的水溶液在室温下混合,12 h后形成凝胶。通过XRD考察凝胶化机制,以溶菌酶为模拟药物,考察凝胶的释药特性,通过扫描电镜考察凝胶的形貌,采用MTT法考察凝胶的细胞毒性。 结果与结论：成功得到聚乳酸/聚乙二醇的三嵌段共聚物,在嵌段共聚物中,聚乳酸嵌段和聚乙二醇嵌段都能结晶,但以聚乙二醇嵌段的结晶为主。通过XRD证明凝胶中存在空间异构复合作用,溶菌酶在凝胶中通过凝胶的溶蚀和降解行为,在7 d之内释放完全。通过扫描电镜观察到冻干的水凝胶呈三维贯穿的多孔结构,空隙尺寸在50~100 μm 之间。鼠成纤维细胞与浓度为100%的凝胶浸提液共培养72 h之后,细胞的存活率为99.3%。     

Orbital T-cell Lymphoma Human T-cell Leukemia Virus-I Infection

This is the first report of orbital involvement in systemic adult T-cell leukemia/lymphoma (ATLL). The etiologic agent of ATLL is the human T-cell leukemia virus-I (HTLV-I), the first retrovirus demonstrated to induce cancer in humans. The diagnosis of ATLL is based on characteristic clinicopathologic features in combination with serologic or virologic evidence of HTLV-I infection. Serum antibodies to HTLV-I were identified by immunofluorescent microscopy. Viral particles characteristic of HTLV-I were found in a culture of the patient's peripheral blood lymphocytes. The patient was a native of the Caribbean, one of the known endemic foci of HTLV-I infection. Adult T-cell leukemia/lymphoma should be considered in the differential diagnosis of orbital T-cell lymphomas.     

软组织激光全息扫描鼻眶窝的三维数字图像分析

目的　介绍三维扫描仪在非接触条件下采集面部软组织精确数据的方法 ,为临床整形提供标准的鼻眶窝三维测量数据。方法　应用三维激光扫描仪和Geomagic软件 ,采集 12例标准汉族人的颜面轮廓 ,并对鼻眶窝进行数据测量和分析。结果　通过三维激光扫描和逆向工程软件可以再现出面部形态有意义的任一角度的三维图像 ,且精确度达到 0 0 1mm ,实验初步确定了鼻眶窝最低点的三维定位 ,描述了鼻眶窝的三维形态特征。结论　此方法可以全面反映鼻眶窝与周围结构形态学上的相互关系 ,三维激光扫描是实现术前设计、手术模拟和术后效果评价的新途径