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.     

Patient-proxy response comparability on measures of patient health and functional status

The present study evaluates the response comparability between 361 elderly hip fracture patients admitted from the community to seven Baltimore area hospitals between 1984 and 1986 and interviewer selected proxies on items pertaining to patients' pre-fracture health and functional status. Agreement across items ranges from very poor to good and varies with respect to the health or functional area assessed. Proxies tend to overestimate patient disability relative to the patients themselves, especially with regard to capacity to perform instrumental activities of daily living. Although proxies who report the greatest contact with patients respond most comparably to the patients, when they do disagree, proxies with the greatest patient contact tend to overestimate patient disability. The authors suggest that attention to item construction and phrasing may improve response comparability.     

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.     

Safety and reliability of external fixation for basicervical and intertrochanteric fractures in high-risk elderly patients

Forty elderly patients with basicervical and pertrochanteric fractures were managed with uniplanar AO external fixator under regional anaesthetic block of the femoral nerve and lateral cutaneous nerve of the thigh from April 2003 to March 2006. The mean age of the patients was 67.9 ± 5.5 years. External fixator application was performed under radiological control after closed reduction had been obtained. Comorbid factors, duration of surgery, duration of hospitalisation, complications, walking ability, time to union and mortality rate were recorded. Patients were followed up for a mean period of 12 ± 4.5 months. Superficial pin tract infection occurred in 13 patients, healing in varus >10° and with shortening >2 cm occurred in six patients, and one patient suffered a spontaneous ipsilateral femoral neck fracture after removal of the fixator. The mean time for union was 10.4 ± 1.2 weeks. Rapid union rate and minor complications obtained in the present study are comparable to those obtained with standard internal fixation techniques. Minimal intraoperative blood loss, short operative time and early patient mobilisation are advantages signifying uniplanar external fixator application under regional anaesthetic block to be a viable option in treatment of basicervical and pertrochanteric fractures in high-risk elderly patients.     

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.     

Arthroscopic Chondral Cyst Excision in a Stiff Perthes’ Hip

Persistent hip stiffness in Perthes’ disease indicates a poor prognosis and is a therapeutic challenge. We report a case of a 13-year-old boy with a stiff Perthes’ hip that was nonresponsive to prolonged nonsurgical treatment. Imaging revealed Catterall group IV Perthes’ disease in an advanced reossification stage, with a focal defect in the weight-bearing area of the capital femoral epiphysis. A focal, compressible chondral elevation was detected on hip arthroscopy; on incision, flocculent fluid was released. After the cyst was excised, microfracture revascularization of the chondral defect was undertaken. Postoperatively, the patient had immediate pain relief, correction of deformity, and restoration of painless range of motion; this has continued for 4 years since surgery was performed. Persistence of an unhealed necrotic segment in Perthes’ disease has traditionally been associated with osteochondritis dissecans; however, in this case, the unhealed and nonossified segment produced an elevated painful chondral cyst that caused spasm and stiffness of the hip. Although 2 distinct types of chondral lesions have been described in Perthes’ disease, stiffness arising because of these lesions has not been reported. Patients with this unusual third type of chondral lesion of the capital femoral epiphysis, which causes persistent stiffness in Perthes’ hip, may be identified and successfully treated with the use of arthroscopic techniques.     

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.     

Hip fracture incidence in the canton of Vaud,Switzerland, 1986–1991

The objective of this study was to estimate the incidence of hip fracture in the canton of Vaud, Switzerland (total population 584 000), for the period 1986–1991 using routine hospital discharge data collected by the Cantonal Service of Statistical Research and Information (SCRIS). For the survey period, the estimated average annual crude incidence rate of hip fractures was 167 per 100 000 persons aged 20 or older (241 for women and 84 for men). For the population aged 50 years or older, the crude incidence rate was 388 per 100 000 persons (546 for women and 185 for men). The average annual age-specific rates rose exponentially by successive 5-year age groups. The median age of patients at the time of the fracture was 82 years in women and 74 years in men. There was no significant difference between the total number of cervical and trochanteric fractures. Between the ages of 20 and 84 years, the cumulative risk for a woman to be admitted to hospital with a hip fracture was twice that of a man (15.8% vs 7.8%). From 1986 to 1991, the age- and sex-adjusted incidence, like the ratio of cervical to trochanteric fractures, did not show any significant trend, although it was consistent with an increase in men (p=0.09). However, the annual number of fractures rose from 644 to 776, particularly among very aged men. The mean length of stay in the acute care hospital fell from 38 days in 1986 to 25 days in 1991. Finally, the comparison of these results with those obtained in 1986 for the same population from more exhaustive sources has confirmed the provision of a consistent, although overestimated, assessment of hip fracture incidence by means of these routine hospital statistics in the canton of Vaud, Switzerland.