Effects of a bone graft substitute consisting of porous gradient HA/ZrO2 and gelatin/chitosan slow-release hydrogel containing BMP-2 and BMSCs on lumbar vertebral defect repair in rhesus monkey.

Dense biomaterial plays an important role in bone replacement. However, it fails to induce bone cell migration into graft material. In the present study, a novel bone graft substitute (BGS) consisting of porous gradient hydroxyapatite/zirconia composite (PGHC) and gelatin/chitosan slow-release hydrogel containing bone morphogenetic protein 2 and bone mesenchymal stem cells was designed and prepared to repair lumbar vertebral defects. The morphological characteristics of the BGS evaluated by a scanning electron microscope showed that it had a three-dimensional network structure with uniformly distributed chitosan microspheres on the surfaces of the graft material and the interior of the pores. Then, BGS (Group A), PGHC (Group B), or autologous bone (Group C) was implanted into lumbar vertebral body defects in a total of 24 healthy rhesus monkeys. After 8 and 16 weeks, anteroposterior and lateral radiographs of the lumbar spine, microcomputed tomography, histomorphometry, biomechanical testing, and biochemical testing for bone matrix markers, including Type I collagen, osteocalcin, osteopontin, basic fibroblast growth factor, alkaline phosphatase, and vascular endothelial growth factor, were performed to examine the reparative efficacy of the BGS and PGHC. The BGS displayed excellent ability to repair the lumbar vertebral defect in rhesus monkeys. Radiography, microcomputed tomography scanning, and histomorphological characterization showed that the newly formed bone volume in the interior of the pores in the BGS was significantly higher than in the PGHC. The results of biomechanical testing indicated that the vertebral body compression strength of the PGHC implant was lower than the other implants. Reverse-transcription polymerase chain reaction and western blot analyses showed that the expression of bone-related proteins in the BGS implant was significantly higher than in the PGHC implant. The BGS displayed reparative effects similar to autologous bone. Therefore, BGS use in vertebral bone defect repair appears promising.

Treatment of Calcified Insertional Achilles Tendinopathy by the Posterior Midline Approach.

The present study investigated the clinical outcomes of the posterior midline approach in the treatment of 34 patients with significantly calcified insertional Achilles tendinopathy. The posterior midline approach was applied for the surgical treatment of 34 patients with chronic significantly calcified insertional Achilles tendinopathy after failed conservative treatment. Gastrocnemius recession was performed simultaneously for patients with gastrocnemius contracture. The Fowler-Philip angle and parallel pitch lines were measured before surgery, and the visual analog scale, Tegner score, and Victorian Institute of Sport tendon study group score were recorded before and after surgery. The mean follow-up period was 45.2 ± 17.7 (range 24 to 84) months. After surgery, the visual analog scale score had decreased notably, and the Tegner score and Victorian Institute of Sport tendon study group score had increased significantly. The posterior midline approach can achieve satisfactory outcomes in the treatment of significantly calcified insertional Achilles tendinopathy, and gastrocnemius recession (Strayer procedure) should be performed for patients with gastrocnemius contracture to improve the surgical outcome.

Evaluation of porous gradient hydroxyapatite/zirconia composites for repair of lumbar vertebra defect in dogs.

OBJECTIVE: To evaluate the effects of porous gradient composites with hydroxyapatite/zirconia and autologous iliac in repair of lumbar vertebra body defects in dogs. METHODS: (1) New porous gradient hydroxyapatite/zirconia composites were prepared using foam immersion, gradient compound and high temperature sintering; (2) A total of 18 adult beagle dogs, aged five to eight months and weighted 10-13 kg, were randomly assigned into two subgroups, which were implanted with new porous gradient hydroxyapatite/zirconia composites (subgroup A in 12) or autologous iliac bone (subgroup B in 6); (3) The post-operative data were analyzed and compared between the subgroups to repair the vertebral body defect by roentgenoscopy, morphology and biomechanics. RESULTS: The porosity of new porous gradient hydroxyapatite/zirconia composites is at 25 poles per inch, and the size of pores is at between 150 and 300 µm. The post-operative roentgenoscopy displayed that new-bone formation is increased gradually, and the interface between composites and host-bone becomes became blur, and the new-bone around the composites were integrated into host-bone at 24 weeks postoperatively in subgroup A. As to subgroup B, the resorption and restructure were found at six weeks after the surgery, and the graft-bone and host-bone have been integrated completely without obvious boundary at 24 weeks postoperatively. Histomorphologic study showed that the amount of bone within pores of the porous gradient hydroxyapatite/zirconia composites increased continuously with a prolonged implantation time, and that partial composites were degradated and replaced by new-bone trabeculae. There was no significant difference between subgroups (P > 0.05) in the ultimate compressive strengths. CONCLUSION: New porous gradient hydroxyapatite/zirconia composites can promote the repair of bony defect, and induce bone tissue to ingrow into the pores, which may be applied widely to the treatment of bony defect in the future.

Multivariate analysis of the prognosis of 37 chondrosarcoma patients.

OBJECTIVE: The current study aimedto screen for possible factors which affect prognosis of chondrosarcoma. METHODS: Thirty seven cases were selected and analyzed statistically. The patients received surgical treatment at our hospital between December 2005 and March 2008. All of them had complete follow-up data. The survival rates were calculated by univariate analysis using the Kaplan-Meier method and tested by Log-rank. χ2 or Fisher exact tests were carried out for the numeration data. The significant indexes after univariate analysis were then analyzed by multivariate analysis using COX regression model. Based on the literature, factors of gender, age, disease course, tumor location, Enneking grades, surgical approaches, distant metastasis and local recurrence were examined. RESULTS: Univariate analysis showed that there were significant differences in Enneking grades, surgical approaches and distant metastasis related to the patients' 3-year survival rate after surgery (P<0.001). No significant difference was not found in gender, age, disease course, tumor location or local recurrence (P>0.05). Multivariate analysis showed that Enneking grade (P=0.007) and surgical approaches (P=0.010) were independent factors affecting the prognosis of chondrosarcoma, but distant metastasis was not (P=0.942). CONCLUSION: Enneking grades, surgical approaches and distant metastasis are risk factors for prognosis of chondrosarcoma, among which the former two are independent factors.

Difference of adherence, proliferation and osteogenesis of mesenchymal stem cells cultured on different HA/ZrO2 composites.

OBJECTIVE: To study the adherence, proliferation and osteogenesis of mesenchymal stem cells (MSCs) cultured on different HA/ZrO2 composites. METHODS: The simplex and graded HA/ZrO2 compo-sites were prepared using dry-laid method. The surface topography of the composites was observed by scanning electron microscope (SEM). The MSCs were isolated from rabbits and cultured on experimental groups (simplex HA/ZrO2 composite, graded HA/ZrO2 composite, pure HA or pure ZrO2 coatings respectively) and control group (ordinary culture plate). Then, we observed the adherence, proliferation and osteogenesis of the MSCs, detected the cellular alkaline phosphatase (ALP) activities, extracted total RNA and detected the mRNA expression of collagen I, osteocalcin and osteopontin using the reverse transcription and polymerase chain reaction (RT-PCR) method. RESULTS: The SEM images confirmed that the surface of the simplex HA/ZrO2 composite was coverd by discon-tiguous HA layer with clear visualization of the partial ZrO2 matrix, while the surface of the graded HA/ZrO2 composite was fairly rough with porosity. X-ray diffraction showed that after high temperature sintering, the ZrO2 phase still remained, while the HA phase was transformed to beta-Ca3(PO4)2 , alpha-Ca3(PO4)2 and CaZrO3 phases on the surface of both composites. Cell culture indicated that the HA/ZrO2 composites supported cell attachment. Neither ALP expression nor mRNA expression of collagen I, osteocalcin or osteopontin from RT-PCR results showed significant deviation among four groups. CONCLUSION: Among these four composites, the graded HA/ZrO2 composite promotes the MSCs proliferation and the osteogenic differentiation to a certain extent.

Bilateral Achilles tendon enlargement.

Cerebrotendinous xanthomatosis is a rare, autosomal-recessive, lipid-storage disease with accumulation of cholestanol in most tissues, particularly within the Achilles tendons. It has been characterized both clinically and biochemically, and recently from the molecular biological aspect as well. Juvenile cataract, childhood diarrhea, mental retardation, cerebellar ataxia, and tendon xanthomas are the most prominent features of this disease. Bilateral symmetrical firm masses of Achilles tendons may be the first symptom the patient recognizes because it can jeopardize his or her ability to walk. However, the treatment strategies for tendon tumors vary. In a recent case, we diagnosed the disease properly, according to the clinical manifestations and the radiological and laboratory examinations. The genetic mutation was characterized by analyzing sterol 27-hydroxylase from the patient's family (located on nucleotide 599) and led to a nonsense mutation. It is a unique type of mutation that has never been reported to our knowledge. Tendon lesions are characterized by the loss of muscle fibers and accumulation of lipid products. To help the patient regain the strength of the Achilles tendon and walking abilities, a large area of tendon tumor was excised, followed by reconstruction with a tibialis posterior allograft, which is the second strongest tendon in the foot and ankle. Although the use of this type of graft is uncommon, the final result was satisfactory. At the 10-month follow-up examination, the patient could walk easily without pain. This case report suggests that the surgical procedure will provide an alternative for the repair of large-area degenerative Achilles tendons.

[Resection pseudoarthrosis for pelvic malignant tumors around acetabular].

OBJECTIVE: To discuss the resection pseudoarthrosis for pelvic malignant tumors around acetabular. METHODS: From May 1997 to June 2005, 25 patients with malignant tumors around acetabular were treated surgically with resection pseudoarthrosis. The series comprised 15 males and 10 females with an average age of 42 years old (range from 16 to 75 years old). There were 4 osteosarcomas, 12 chondrosarcomas, 1 Ewing's sarcoma, 1 neuroectodermal tumor, 1 myeloma, 1 malignant fibrohistiocytoma, 2 synovial sarcomas, and 3 metastases. Pseudoarthrosis was performed after resection of pelvic malignant tumors around acetabular. The affected side was protected postoperatively by skin traction with 2 - 3 kg weight for 6 to 8 weeks. After then, the patients walked gradually with a cane. RESULTS: Among 25 patients, 6 had complications (24%). At a follow-up ranging from 3 to 10 years, 11 patients died of lung metastases, 2 relapsed, 12 remained alive free of disease. There was an average crispation of 5 cm (range from 2.5 to 7.5 cm). The patients were functionally evaluated according to Enneking's MSTS criteria in 1993. The average MSTS functional score was 17 points (12 to 19 points). After 3 months postoperative, the patients could sit normally, walk with a cane, and even walk limpingly without cane. CONCLUSIONS: Resection pseudoarthrosis for pelvic malignant tumors around acetabular results in good clinical results at the time of mid-term and long-term follow-up. And pseudoarthrosis is advisable especially for patients with malignant highly tumors around acetabular, poor soft tissue reconstruction condition, high risk for infection, poor economy.

Enhancement effect of adenovirus-mediated antisense c-myc and caffeine on the cytotoxicity of cisplatin in osteosarcoma cell lines.

AIMS: Studies on cancer biology have shown that overexpression of oncogenes (with or without functional loss of tumor suppressor genes), which is responsible for the progression of human malignancies via a multistep process, may be reduced by antisense technology. Caffeine enhances the effect of cisplatin (CDDP) chemotherapy on osteosarcoma cells. We constructed the recombinant adenovirus (Myc-AS) encoding the antisense c-myc fragment and investigated the synergic effect of caffeine and Myc-AS on the in vitro sensitivity of osteosarcoma MG-63 cells to cisplatin. METHODS: The recombinant adenovirus (Myc-AS) encoding the antisense c-myc fragment was constructed by cloning c-myc cDNA of about 750 bp in a reverse direction into adenovirus vector, then undergoing recombination, amplification and complementation in vivo. Myc-AS and caffeine were used either alone or in combination with CDDP to treat osteosarcoma MG-63 cells in vitro. Western blot, MTT, flow cytometry (FCM) and electron microscopy were used to evaluate the expression of c-myc protein, tumor cell proliferation in vitro and apoptosis and to perform cell cycle analysis. RESULTS: Myc-AS encoding antisense c-myc fragment was obtained with a titer of 2 x 10(9) pfu/ml. Myc-AS downregulated the expression of c-myc protein after transfecting MG-63 cells for 48 h, induced tumor cell apoptosis and inhibited tumor cell proliferation in vitro. Myc-AS or caffeine can enhance the cytotoxic effects of 2.0 and 5.0 microg/ml CDDP on MG-63 cells. Moreover, the significantly enhancing effect of the Myc-AS-caffeine combination on CDDP chemotherapy of MG-63 cells was not restricted to apoptosis but also decreased tumor cell proliferation in vitro. Expression of the apoptosis-associated bcl-2 gene was downregulated and bax was upregulated, with no changes in E2F-1 expression. FCM analysis showed that CDDP treatment induced a block in S phase, and caffeine reversed this block and accelerated cell progression through the S phase. CONCLUSIONS: Myc-AS can induce obvious G2/M phase arrest in transfected cells. Myc-AS combined with caffeine can enhance apoptosis induction and chemotherapeutic effects of CDDP on osteosarcoma MG-63 cells.

[Long-term result of fibula grafting for reconstruction of the distal radius after giant cell tumor excision].

OBJECTIVE: To observe the long-term result of fibula grafting for reconstruction of the distal radius after giant cell tumor excision. METHODS: From March 1994 to November 2004, 31 cases of fibula grafting for reconstruction of the distal radius for giant cell tumors performed were analysed. There were 12 males and 19 females. The patients were from 19 to 48 years old, and the mean age was 31 years. Twenty-four patients had Campanacci grade 3 lesions, and 7 patients had Campanacci grade 2 lesions. There were 6 cases of vascularized fibular grafting and 25 cases of non-vascularized fibular grafting. All cases were evaluated by clinical and radiologic examinations; the movement of the wrist and the grip strength was measured; the MSTS score and Mayo Wrist scores were calculated. RESULTS: Clinical follow-up time after reconstruction averaged 86.3 months, range from 41 to 169 months. The mean time for bone union at the host-graft junctions was 5.1 months range from 3 to 9 months in vascularized group and 10.3 months range from 7 to 15 months in non-vascularized group. One patient who had non-vascularized fibula grafting developed non-union at the host-graft junction, and one patient had local recurrence (3.2%). Five patients developed an wrist dislocation after surgery. The average movements of the wrist were: 67.3 +/- 9.4 degrees of extension, 31.2 +/- 5.1 degrees of flexion, 14.1 +/- 4.7 degrees of radial deviation, 19.4 +/- 3.9 degrees of ulnar deviation, 33.8 +/- 6.6 degrees of pronation, 15.3 +/- 4.0 degrees of supination. Average grip strength was 33.1 kg range from 15.5 to 52.1 kg. Compared with the contralateral side, there were accounted for 73%. MSTS score averaged 25.5 from 23 to 29, Mayo wrist score averaged 56 from 40 to 65. CONCLUSIONS: En bloc resection of giant cell tumor of the distal radius followed by reconstruction with a fibula graft is proved to be an effective method and results in a good functional outcome at long term follow-up evaluation. The stability of wrist is achieved by reconstruction of the capsule.

[The treatment of knee joint peripheral fractures and/or dislocations with vascular injury].

OBJECTIVE: To investigate the effect and influence factors on knee joint peripheral fractures and/or dislocations with an associated vascular injury through retrospectively study. METHODS: From March 2002 to November 2007 31 patients with knee joint peripheral fractures and/or dislocations with an associated vascular injury were treated, including 24 males and 7 females with a mean age of 41 years (range from 21 to 62 years). Definite diagnosis of vascular injury by combining colored ultrasonic, CTA, operative exploration with clinical signs, fixing fractures and/or dislocations with fixators, plates and screws, reconstructing blood circulation based on the condition of the vascular injury by vascular repair, homograft vein or artificial vascular grafting separately and analysing the effects of PSI, diagnosis and treatment methods on salvage lower extremities. RESULTS: Successful reconstruction was carried out in 31 cases, however there were 1 death because of mult-fractures and brain injury and 6 amputation, 24 cases successful salvage followed up mean 24.2 months, 6 cases bone nonunion and infected bone defect were cured by delayed bone planting or bone transportation. Ligaments repair reconstruction of 7 cases knee joint dislocation were done in delayed 3 or 4 weeks after first operation, the good functional rate was 71.4%. CONCLUSIONS: The patients of PSI under 10 grades in knee joint peripheral fractures and/or dislocations with an associated vascular injury should been carried out treatment, early definite diagnosis and blood circulation reconstruction are the key factors of successful salvage treatment.

[The surgical therapy of periacetabular malignant tumors].

OBJECTIVE: To study the limb salvage methods and treatment outcomes in malignant periacetabular bone tumors. METHODS: The data of 31 patients of periacetabular malignant tumors who had limb salvage surgery between January 1999 and December 2006 was retrospectively reviewed. There were 14 females and 17 males with a mean age of 53 years (range, 42-75 years). Twenty-four patients had chondrosarcomas, 4 patients had Ewing sarcomas, 1 patient had osteosarcoma, and the remaining 2 patients had metastatic disease. Sixteen patients had Types II pelvic resections, 5 patients had Types I and II pelvic resections, another 5 had Type I and III pelvic resections, and Type I , II and III pelvic resections in the remaining patients. Seventeen patients had reconstructions after tumor resection. RESULTS: The mean follow-up time for all patients was 52 months (range, 12-84 months). Fourteen patients were alive with no evidence of disease, 4 patients were alive with disease at the most recent follow-up, and 13 patients died of disease. The local recurrence rate and mortality rate in 24 patients with chondrosarcomas was 20.8% and 33.3% respectively. Two patients with metastatic disease died at 11 and 34 months postoperatively. One patient with osteosarcoma and 2 patients with Ewing sarcoma died of lung metastases. Enneking scoring system was used to evaluate the functional outcome in 18 alive patients. In 13 patients who had reconstructions, 6 were in excellent, 6 were in good, and 1 was in poor. While in 6 patients who had no reconstructions, 3 were in excellent, 2 were in good, and 1 was in poor. Minor complications occurred in 6 patients. CONCLUSIONS: Clear margin tumor resection with decreased local recurrence rate is critical for limb salvage surgery in periacetabular sarcomas. The ranges of tumor invasion and resection, the principle of individual treatment should be considered in functional reconstruction.

[Endoprosthetic reconstruction after wide resection of primary bone tumor around the knee].

OBJECTIVE: To evaluate the effect and complication of the endoprosthetic reconstruction after wide resection of primary bone tumor around the knee. METHODS: The retrospective analysis was performed on 83 patients undergoing the prosthetic reconstruction after the resection of the primary tumor around the knee between December 1995 and December 2005. All the diagnoses were pathologically confirmed (58 patients with osteosarcoma, 2 with osteosarcomatosis, 1 with parosteal osteosarcoma, 4 with malignant fibrous histiocytoma, 13 with giant cell tumor of bone, 1 with leiomyosarcoma, 2 with Ewing's sarcoma, 2 with chondrosarcoma). The distal femur group was involved in 44 patients, proximal tibia group in 34 (including 33 deficit in proximal tibia, 1 deficit both in proximal tibia and distal femur), total femur replacement group in 5. After operation, the Musculoskeletal Tumor Society (MSTS) score was used to evaluate the recovery of their corresponding functions. RESULTS: The follow-up for 12 - 130 months (with a median of 41 months) revealed that the 3-year survival rate of the prosthesis was 88.2%, and the 5-year survival rate was 82.1%. As for the complications, local recurrence developed in 6 patients, peri-prosthesis infection in 2 patients, aseptic loosening in 2 patients. The mean MSTS core was 25.0 (19.0 - 29.0) in the distal femur group, 24.4 (17.0 - 28.0) in the proximal tibia group, and 19.0 (16.0 - 21.0) in the total femur replacement group. As to the statistical analysis, the function of the former two groups were greater than the latter one (F = 11.666, P < 0.001), however, there was no significant difference between the former 2 groups (F = 0.813, P = 0.370). CONCLUSIONS: Taken together, the tumor prosthesis gives a satisfactory functional outcome after the tumor around the knee is removed with a lower incidence of complication.

Caspase-8 dependent osteosarcoma cell apoptosis induced by proteasome inhibitor MG132.

Many researchers have reported that proteasome inhibitors could induce apoptosis in a variety of cancer cells, such as breast cancer cell, lung cancer cell, and lymphoma cell. However, the effect of proteasome inhibitors on osteocsarcoma cells and the mechanisms are seldom studied. In this study, we found proteasome inhibitor MG132 was an effective inducer of apoptosis in human osteosarcoma MG-63 cells. On normal human diploid fibroblast cells, MG132 did not show any apoptosis-inducing effects. Apoptotic changes such as DNA fragment and apoptotic body were observed in MG132-treated cells and MG132 mostly caused MG-63 cell arrest at G(2)-M-phase by cell cycle analysis. Increased activation of caspase-8, accumulation of p27(Kip1), and an increased ratio of Bax:Bcl-2 were detected by RT-PCR and Western blot analysis. Activation of caspase-3 and caspase-9 were not observed. This suggests that the apoptosis induced by MG132 in MG63 cells is caspase-8 dependent, p27 and bcl-2 family related.

The construction of the eukaryotic expression plasmid pcDNA3.1/azurin and the increased apoptosis of U2OS cells transfected with it.

In our previous study, we demonstrated that azurin could selectively trigger apoptosis in human osteosarcoma cell line U2OS cells. However, the rate of apoptosis (35.8 +/- 3.2%) is not very high, and azurin is too expensive to obtain readily. To solve these problems, we constructed a eukaryotic expression plasmid containing the azurin gene with an influenza virus haemagglutinin 9 peptide HA epitope tag, and transfected the recombinant plasmid pcDNA3.1(+)/azurin into U2OS cells. RT-PCR and Western blot analysis validated the successful transfection and the expression of the azurin-HA protein. Conspicuous apoptosis of the transfected cells was detected by flow cytometry (FCM) and the DNA ladder test. The apoptosis rate reached 64.3 +/- 13.1%. The transcriptional levels of the Bax and p53 genes increased significantly in U2OS cells transfected with pcDNA3.1(+)/azurin, but the Bcl-2 mRNA level decreased. There was no difference in the levels of Bcl-xl mRNA and Survivin mRNA. We propose that the transfection of the recombinant plasmid pcDNA3.1(+)/azurin can significantly induce apoptosis in U2OS cells. This is closely associated with the up-regulation of the transcriptional level of the Bax and p53 genes, and the down-regulation of that of the Bcl-2 gene.

Study of the morphology and biomechanics of sacral fracture.

OBJECTIVE: To observe the morphological characteristics of sacral fracture under different impact loads. METHOD: Ten fresh pelvic specimens were loaded in dynamic or static state. A series of mechanical parameters including the pressure strain and velocity were recorded. Morphological characteristics were observed under scanning electron microscope. RESULTS: The form of sacral fracture was related to the impact energy. Under low energy impact loads, ilium fracture, acetabulum fracture and crista iliaca fracture were found. Under high energy impact loads, three types of sacral fracture occurred according to the classification of Denis: sacral ala fracture, Type I fracture; sacral foramen cataclasm fracture, Type II fracture; central vertebral canal fracture, Type III fracture. Nerve injury of one or two sides was involved in all three types of sacral fracture. The fracture mechanism of sacrum between the dynamic impact and static compression was significantly different. When the impact energy was above 25 J, sacral foramen cataclasm fracture occurred, involving nerve root injury. When it was below 20 J, ilium and sacral fracture was most likely to occur. When it was 20 approximately 25 J, Type I fracture would occur. While in the static test, most of the fracture belonged to ilium or acetabulum fracture. The cross section of sacrum was crackly and the bone board of Haversian system was brittle, which could lead to separation of bone boards and malposition of a few of cross bone boards. CONCLUSIONS: In dynamic state, sacrum fracture mostly belongs to Type I and Type II, and usually involves the nerve roots. Sacrum fracture is relevant to the microstructures, the distribution of the bone trabecula, the osseous lacuna and the Haversian system of sacrum. The fracture of ilium and acetabulum more frequently appears in static state, with slight wound of peripheral tissues.

Recombinant antisense C-myc adenovirus increase in vitro sensitivity of osteosarcoma MG-63 cells to cisplatin.

C-myc is an oncogene with the important role of cell proliferation controller. It has been found to be amplified and overexpressed in osteosarcoma. Moreover, it can promote cell transformation and induce metastatic features. Some studies showed that overexpression of c-myc could induce resistance in response to antineoplastic agents. Currently, we constructed the recombinant adenovirus (Ad-Asc-myc) encoding antisense c-myc fragment and investigated its effect on the in vitro sensitivity of osteosarcoma MG-63 cells to cisplatin(CDDP). The osteosarcoma MG-63 cells were transfected by the Ad-Asc-myc in vitro, and Western Blot, MTT assay, RT-PCR, flow cytometry (FCM), and transmission electron microscopy (TEM) were used to study expression of c-myc and caspase-3 protein, tumor cell proliferation in vitro, cell apoptotic morphology and cell cycle change. Ad-Asc-myc encoding antisense c-myc fragment was obtained with the titer of 2.0 x 10(9) pfu/ml. Ad-Asc-myc downregulated the expression of c-myc protein after transfected MG-63 cells for 48 hours, combined with the treatment of 2.0, 5.0 microg/ml cisplatin for 2 hours can inhibited tumor cells proliferation in vitro by 33.4 and 54.2 percent, respectively, which had significant difference compared with control recombinant adenovirus (Ad-LacZ) groups (P < 0.05). RT-PCR revealed that Ad-Asc-myc downregulated expression of bcl-2 and upregulated expression of Bax, and no appreciable changes were observed in the expression of E2F-1. Detection of caspase-3 protein TEM, and FCM analysis showed that Ad-Asc-myc could induce apoptosis of transfected cells, which was enhanced by the treatment of cisplatin. Cell cycle analysis showed that obvious G(2)/M phase arrested in transfected cells. In conclusion, Ad-Asc-myc increased the in vitro sensitivity of osteosarcoma MG-63 cells to cisplatin as well as induced apoptosis.

[The choice strategy of surgical treatment for giant cell tumor close to the knee].

OBJECTIVE: To retrospectively study and analyze the methods of the surgery management for giant cell tumor close to the knee. METHODS: A retrospective analysis was performed in 121 patients who underwent surgical treatment for giant cell tumor close to the knee between 1978 and 1997. There were 71 cases had been managed with an intralesional procedure of the tumor (curettage, freezing with liquid nitrogen and autograft or allograft, Group 1), 50 cases with a semi-arthroplasty using allograft after en bloc resection (Group 2). According to the relation of the clinical signs and symptoms, tumor character, operative method and local recurrence, limp function, complication were evaluated. Based on the figure of tumor lesion on CT, a new formulation of treatment was given: (1) I diameter of tumor 3/4, en bloc resection and reconstruction. The prospectively collected records of 65 cases of patients, 45 cases with curettage, heat cauterization with electrocautery and phenol, autograft and cement (Group 1), 20 cases with arthroplasty using prosthetic (Group 2), who had a giant-cell tumor closed knee, were reviewed to determine feasibility of the new formulation of treatment. RESULTS: The first duration, the rate of the local recurrence between 2 groups showed no statistical difference. There were less complication rate and better limp function after using two different surgical treatment. The second duration, there were no statistical difference with the rate of the local recurrence, complication, and limp function. The number of patients who managed with en bloc resection and reconstruction decreased. CONCLUSIONS: The choice strategy of surgical treatment for giant cell tumor close to the knee should be based on the figure of tumor lesion on CT. It gives a new formulation of treatment to choice of an intralesional procedure and en bloc resection. An effective intralesional procedure should be the method of the first choice.

[Cytotoxicity and apoptosis of human osteosarcoma U2OS cells induced by recombinant soluble AZURIN].

OBJECTIVE: To investigate the effects of recombinant AZURIN protein of P. aeruginosa on growth and apoptosis of U2OS cells. METHODS: The AZURIN gene was amplified from the genome of P.aeruginosa by PCR, and cloned into prokaryotic expression vector pQE30. The soluble AZURIN protein was expressed in E. coli cells M15, then purified and refolded. After treatment of AZURIN, the cell cycle, proliferation and apoptosis were determined by morphological observation, MTT assay, flow cytometry(FCM) and DNA fragmentation assay. Mitochondrial membrane potential(DeltaPsim) was measured by FCM. RESULTS: The purity of recombinant protein AZURIN reached to 99.1%. Proliferation of U2OS cells were significantly inhibited 12 h after AZURIN (100-200 mg/L) treatment. Apoptosis peak and DNA ladder were observed. Mitochondrial membrane potential decreased gradually from 12 h to 72 h after AZURIN treatment. CONCLUSION: The recombinant AZURIN inhibit the growth of the human osteosarcoma U2OS cells and inducs apoptosis in vitroìwhich may be associated with the decrease of mitochondrial membrane potential.

[Cytotoxic effect of cisplatin with proteasome inhibitor on osteosarcoma cells].

OBJECTIVE: To observe the cytotoxic effect of cisplatin with proteasome inhibitor on osteosarcoma cells. METHODS: Cell survival was tested by MTT, apoptotic morphology was observed by electron microscopy, apoptotic rate was analyzed by flow cytometry, the transcription level of excision repair cross complementation-1 (ERCC-1) was tested by reverse transcription polymerase reaction. RESULTS: Compared with cells treated with cisplatin alone, cells treated with cisplatin and proteasome inhibitor showed a decreased survival rate, more typical apoptotic morphology, higher apoptotic rate [(14.37 +/-2.37)% vs. (50.93 +/-4.84)%, P<0.01)], and lower transcription level of excision repair cross complementation-1. CONCLUSION: Proteasome inhibitor could increase the cytotoxic effect of cisplatin on osteosarcoma cells and promote cisplatin-induced osteosarcoma apoptosis. These effects may be associated with the decreased transcription of excision repair cross complementation-1.