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.     

A clinical and radiological two‐year follow‐up study of maxillary overdentures on osseointegrated implants

In order to satisfy the need to restore the aesthetics, phonetics and comfort and to facilitate optimal hygiene procedures, 20 edentulous patients were treated with a new concept of overdenture therapy on implants ad modum Brånemark. After 24±3.5 months the patients were re‐examined. They were asked to answer a questionnaire and use a Visual Analogue Scale (VAS) to give their opinion on the prosthetic treatment. The results indicate that an implant‐retained overdenture in the maxilla with this design can satisfy the patients needs in aesthetics, phonetics and comfort and can 1 facilitate oral hygiene measures.     

旋转铰链型与单纯铰链型膝关节肿瘤假体置换的临床比较研究

目的 研究膝关节肿瘤保肢手术两种假体置换的术后效果及其比较.方法 随访我院1999年6月2006年3月治疗的72例膝关节肿瘤患者，失访9例，余63例中40例采用单纯铰链型假体置换(A组)，23例采用旋转铰链型假体置换（B组）63例随访时间9月~8年平均3年9个月，按MSTS膝关节评分标准、ambulation scores、关节屈伸度及感染、复发、手术时间进行评估。结果：A组：手术时间2.6625±0.3362h，复发5例，转移死亡3例，感染2例； B组：手术时间2.5722±0.2878h，复发3例，转移死亡2例，感染2例 。B组1例术后发生旋转轴聚乙烯轴套断裂关节脱位，再次手术更换轴套后未再出现并发症，两组无假体松动病例。两组手术时间无统计学意义；去除复发及转移死亡病例后,剩50例, A组32例， MSTS评分平均23.0/30分。 B组18例，MSTS评分平均23.7/30分。两组MSTS评分p>0.05，无统计学意义；ambulation scores各分项总分均p<0.05，有统计学意义．两组关节伸直时为0°或接近0°,屈曲度A组119.3750±17.49°，B组125.0000±15.34°，无统计学意义（p>0.05）。结论： 1. 按ambulation scores标准，在步行舒适度和快速步行方面，旋转型铰链假体置换组与单纯铰链型假体置换比较有统计学意义；2.而MSTS标准则未能体现出两组术后功能方面的统计学意义，因此ambulation scores较MSTS评分更灵敏，更适合对膝关节保肢术后功能评价；3.两组在手术时间、术后临床屈伸功能及并发症方面，如复发、感染，未见显著差别，单纯铰链型不会出现脱位，而可旋转铰链型假体有脱位的可能。     

升主动脉成形术中期效果分析

Objective Reduction ascending aortoplasty is an alternative procdure to the replacement of the ascending aorts in case of ascending aorta dilation. However,its applicabikity is still under debate.This retrospective study was designed to evaluuate the midterm follow-up of unsupported ascending reduction aortoplasty for of the ascending aorta in petients with aortic valve dis- ease.Methods From October ,1996 to April,2007, a total of 54 patients with aortic valve disease and dilatation of the ascending aorta underwent unsupported reduction aortoplasty in combination with aortic valve replacement at our institution The diameter of the ascending aorta was measyred before and early after sugery and then later between 13 and 96 menths [mean (23 ±16)months] posto- perativeiy using echocardiography.Results Two patients were dead with thean overall perioperative mortality rate was of 3.7%. The reduction aortoplasty decreased the diameter of the aorta from (45.77±6.02) mm p～eope～afive]y to (34.67 ～4.81) mm early after surgery (P<0.01). During follow-up, the diameter d aorta increased from (34.67±4.81) mm early after surgery to (37.65± 6.35) mm after a mean follow-up of (23±16) months (P<0.01), including the diameters are greater than > 45 mm within 5 pa- tients. Aortic stenosis and an early postoperative diameter greater than 40 mm m'e independent risk factors for redilatation. Conchusion Because of the unsatisfied midterm follow-up redilation of unsupported reduction aortoplasty for dilation of the ascending aorta with aortic valve disease, this group of patients needs continued intimate fallow-up or even reoperation. The patients of stenosis is the surtable indication for RAA, and it is necessary to reduce the diameter of aorta to be lees than 40 mm to prevent redilation.     

High resolution solid-state 29si nmr spectroscopy of silicone gels used to fill breast prostheses

We have used ²⁹Si solid-state nuclear magnetic resonance (NMR) spectroscopy to study the chemical structure of the silicone gels in virgin and explanted breast prostheses. Despite evidences of alteration in the morphological appearance of the silicone gel inside the breast prosthesis, our results do not reveal changes in the chemical nature and structure of the silicone gels after implantation. In addition to the main ²⁹Si resonance peak at ?22.26 ppm that corresponds to the resonance frequency of the D repeat unit of the polysiloxane chains, the high sensitivity of our NMR technique allows the detection of very low concentrations of silicone compounds. Within our experimental detection limit of 0.2%, no signal between ?90 ppm and ?150 ppm are observed. This indicates that no silica products are present inside the gel of the prostheses. Furthermore, our ²⁹Si NMR spectra indicate differences in the chemical compositions of the silicone gels from different manufacturers.     

Image technique optimization in MR imaging of a titanium alloy joint prosthesis

The purpose of this study was to explore systematically the effect of the imaging parameters changeable by the user in spin-echo (SE) imaging sequences to minimize image distortion when imaging joint prostheses. A titanium alloy hip joint prosthesis was studied at 1.0 T. The SE imaging parameters were bandwidth/pixel (BW/p), TE, strength of encoding gradients (matrix size), echo train length (ETL), and direction of phase and frequency encoding. The effect of ETL in rapid acquisition relaxation enhanced (RARE) sequences was also evaluated with a turbo-SE sequence using a different ETL with the same TR and an effective TE. It is concluded that an optimized image quality can be achieved in SE imaging by using a high bandwidth/pixel value (at least 130 Hz/pixel), a high resolution matrix (256–512), sequences with multiple refocusing, and a frequency-encoding axis parallel to the long axis of the prosthesis. The degree of distortion is reduced with this optimized technique.     

Factors influencing survival of reconstructions. Consensus report of Working Group 2

Abstract: In order to evaluate the level of evidence of factors influencing the survival of reconstructions, systematic reviews of the relevant literature were prepared by a group of rapporteurs. The review papers were circulated to the members of the group before the conference and formed the basis for group and panel discussions. Subsequently, modifications were added to the review papers, and suggestions for consensus statements concerning the following topics were prepared and again critically reviewed in the group and in the plenum: Impact of (i) periodontal disease on the survival of tooth-supported reconstructions, (ii) post-surgical factors as supportive therapy on the survival of implant supported reconstructions, (iii) technical and/or biological complications on the survival of different types of reconstructions, (iiii) material choice for reconstructions on the survival of single crowns and fixed dental prostheses.     

Immediate versus delayed chemotherapy in patients with asymptomatic incurable metastatic cancer

Aim: To examine the evidence of benefit in initiating immediate chemotherapy in patients with newly diagnosed asymptomatic metastatic incurable cancer, compared with delaying chemotherapy until symptomatic progression. Methods: Through an extensive review of published reports, we examined the biological, clinical, psychological and ethical background of the issue and reported on the available clinical trial evidence in a variety of tumor types. Results: Only a limited number of clinical trials have directly examined the role of immediate versus delayed chemotherapy in patients with incurable asymptomatic metastatic cancer. Small studies in mesothelioma, colorectal cancer, breast cancer, myeloma, and low‐grade lymphoma suggest no survival benefit for the immediate initiation of chemotherapy. However, there was no evidence in other tumor types. Conclusion: The appropriate timing of chemotherapy initiation in an asymptomatic patient with metastatic cancer remains a substantial question in oncology. Many factors are likely to impact on the decision. However, little if any evidence demonstrates a clear advantage in the immediate initiation of chemotherapy in this setting.     

踝关节病的人工踝关节置换

[目的]探讨人工踝关节置换治疗踝关节病的疗效。[方法]对1999~2004年1月的18例患者包括骨性踝关节炎6例,创伤性踝关节炎9例,局限性距骨缺血坏死2例,踝关节融合后1例,均采用L ink STAR假体3构件套进行人工踝关节置换。18例中,男13例,女5例;平均年龄47.7岁(38~67)。[结果]随访平均3 a 9个月(1~5 a)。按Kofoed评价系统观察疗效,优(85~100)16例,良(75~84)2例,无可(70~74)和差(<70)。患足背屈平均8°(范围6°~12°),跖屈12°(范围8°~16°),背屈和跖屈平均16°(11°~23°)。并发症有切口皮缘坏死2例,无足内、外翻和影像学松动。[结论]人工踝关节置换是治疗和替代踝关节多种疾患疼痛和需要融合的良好方法。     

Voice prosthesis insertion after endoscopic balloon-catheter dilatation in case of a stenotic hypopharyngo-oesophageal junction

Stenosis of the hypopharyngo-oesophageal junction can be a rare complication of laryngectomy and/or partial pharyngectomy and makes the insertion of voice prosthesis extremely difficult. This study describes the authors’ experiences gained by endoscopic balloon-catheter dilatation of hypopharyngo-oesophageal stenoses prior to implantation of voice prostheses in four cases. In two patients a single balloon-catheter dilatation resulted in wide enough pharyngo-oesophageal lumen on the long run. The average prosthesis wearing-times were 6.8 months in case 1 and 4.6 months in case 2, corresponding to the published literature data. In case 3, repeated dilatation of the pharyngo-oesophageal transition had proved to be unsuccessful despite taking every effort with the endoscopic balloon-catheter method. Having excised the stenotic segment, reconstruction with pectoralis major myocutaneous flap (PMMF) was indicated. Eighteen months later, a repeated restenosis was observed and a free jejunal flap needed to be performed as a final solution. In case 4, the insertion was carried out into a previously dilated jejunal free flap, which became gradually ischemic and stenotic since the major head-and neck procedure was carried out that resulted in prosthesis rejection after just 1 week. The authors emphasize that correct indication of pedicled and free flaps in head and neck reconstruction is a prerequisite from the aspect of prevention of pharyngo-oesophageal strictures. Endoscopic balloon-catheter dilatation is a safe and established method for dilatating hypopharyngo-oesophageal stenoses of different origin. The procedure provides maximum patient benefit with minimal trauma and morbidity; moreover, facilitates insertion of voice prostheses. However, a single balloon-catheter dilatation cannot always result in wide enough oesophageal lumen on the long run (case 3). Insertion of a voice prosthesis into a previously dilated ischemic jejunal segment is challenging and avoidable due to risks of complications.