Arthroscopic Treatment of Calcific Tendinitis of Gemellus Superior and Gemellus Inferior: A Case Report and Literature Review.

BACKGROUND: Tendon calcification is a common disease, and it could happen in the tendons of the shoulder, wrist, etc. However, tendon calcification in the superior and inferior gemellus is rare, and in this region is likely to be misdiagnosed. CASE PRESENTATION: Here, our case report first reported a 53-year-old female patient with an unusual case of calcific tendinitis of the gemellus superior and gemellus inferior muscles. The patient presented with severe pain in the right hip and lower extremities, not relieved using nonsteroidal anti-inflammatory drugs (NSAIDs). The preoperative physical examination indicated an abnormality in the hip joint. Preoperative imaging confirmed the results of the physical examination and showed a right hip lesion. We did not make a definite diagnosis preoperatively but considered that the patient might have an osteochondroma. However, surgical findings indicated that the lesion was not in the hip capsule on subsequent arthroscopic surgery, which suggested that the preoperative diagnosis might be wrong. We opened the posterior capsule and found a "toothpaste-like" lesion in the superior and inferior gemellus muscles' tendon. We thought this might be the calcified tendon. Then the arthroscopic surgery was finished to remove the lesion, and the removed tissue was sent to the pathology department for pathological examination. The pathological report confirmed the diagnosis of the calcified tendon. Postoperative follow-up was conducted. The effect of the operation was noticeable. Postoperative symptoms were relieved. CONCLUSIONS: Calcification of the tendons of the superior and inferior gemellus muscles can be easily misdiagnosed, and the disease can be treated minimally with arthroscopy.

SP1-induced long non-coding RNA SNHG6 facilitates the carcinogenesis of chondrosarcoma through inhibiting KLF6 by recruiting EZH2.

Small nucleolar RNA host gene 6 (SNHG6) is a newly discovered long non-coding RNA (lncRNA), while the regulatory mechanism of SNHG6 in chondrosarcoma is largely unknown. Here we found that SNHG6 expression was upregulated and showed positive correlation with the progression of chondrosarcoma. Functional assays demonstrated that SNHG6 was required for the proliferation, migration, and invasion of chondrosarcoma cells. Mechanistic study revealed that SNHG6 could recruit EZH2 and maintain high level of H3K27me3 to repress the transcription of tumor-suppressor genes, including KLF6. KLF6 was found to bind to the promoter region of SP1 and restrained its transcription, while SP1 could be recruited to the promoter region of SNHG6 and promoted its transcription to form a positive loop. In summary, this study reveals that SP1-induced SNHG6 forms a positive loop to facilitate the carcinogenesis of chondrosarcoma through the suppression of KLF6 by recruiting EZH2, which manifests the oncogenic function of SNHG6 in chondrosarcoma.

Surgical treatment of thoracolumbar fracture with incomplete lower limb paralysis in a patient with COVID-19.

Since December 2019, COVID-19, an acute infectious disease, has gradually become a global threat. We report a case of thoracolumbar fractures (T12 and L1) and incomplete lower limb paralysis in a patient with COVID-19. After a series of conservative treatment which did not work at all, posterior open reduction and pedicle screw internal fixation of the thoracolumbar fracture were performed in Wuhan Union Hospital. Three weeks later, the patient could stand up and the pneumonia is almost cured. We successfully performed a surgery in a COVID-19 patient, and to our knowledge it is the first operation for a COVID-19 patient ever reported.

Recent advances of drug delivery nanocarriers in osteosarcoma treatment.

Osteosarcoma is the most common primary malignant bone tumor mainly occurred in children and adolescence, and chemotherapy is limited for the side effects and development of drug resistance. Advances in nanotechnology and knowledge of cancer biology have led to significant improvements in developing tumor-targeted drug delivery nanocarriers, and some have even entered clinically application. Delivery of chemotherapeutic agents by functionalized smart nanocarriers could protect the drugs from rapid clearance, prolong the circulating time, and increase the drug concentration at tumor sites, thus enhancing the therapeutic efficacy and reducing side effects. Various drug delivery nanocarriers have been designed and tested for osteosarcoma treatment, but most of them are still at experimental stage, and more further studies are needed before clinical application. In this present review, we briefly describe the types of commonly used nanocarriers in osteosarcoma treatment, and discuss the strategies for osteosarcoma-targeted delivery and controlled release of drugs. The application of nanoparticles in the management of metastatic osteosarcoma is also briefly discussed. The purpose of this article is to present an overview of recent progress of nanoscale drug delivery platforms in osteosarcoma, and inspire new ideas to develop more effective therapeutic options.

Outcome of segmental prosthesis reconstruction for diaphyseal bone tumors: a multi-center retrospective study.

BACKGROUND: The optimal reconstructive method after diaphyseal malignant bone tumor resection remains controversial. This multicenter clinical study was designed to investigate the clinical value and complications of segmental prosthesis in the repair of diaphyseal defects. METHODS: We present 49 patients from three clinical centers treated with wide resection for primary or metastatic bone tumors involving the diaphysis of the femur, tibia, humerus, or ulna, followed by reconstruction using a modular intramedullary segmental prosthesis. RESULTS: Enrolled patients included 23 men and 26 women with a mean age of 63.3 years. Of these, seven patients had primary bone tumors and 42 patients had metastatic lesions. At the mean follow-up of 13.7 months, 17 patients were alive, 31 patients were deceased due to tumor progression, and one patient was dead of another reason. There were eight nononcologic complications (two with radial nerve injury, three with delayed incision healing, two with aseptic loosening in the proximal humerus prosthetic stem and one with structural failure) and three oncologic complications (three with primary tumor recurrence) among all patients. The incidence of complications in primary tumor patients (4/7, 57.1%) was higher than that in patients with metastatic tumors (7/42, 16.7%) (p = 0.036). Aseptic loosening and mechanical complications were not common for patients with primary tumors, although the reconstruction length difference was statistically significant (p = 0.023). No statistically significant differences were observed in limb function, while the mean musculoskeletal tumor society score was 21.2 in femora, 19.6 in humeri, and 17.8 in tibiae (p = 0.134). CONCLUSIONS: Segmental prostheses represent an optional method for the reconstruction of diaphyseal defects in patients with limited life expectancy. Segmental prostheses in the humerus experienced more complications than those used to treat lesions in the femur.

Application and Prospect of Mixed Reality Technology in Medical Field.

Mixed reality (MR) technology is a new digital holographic image technology, which appears in the field of graphics after virtual reality (VR) and augmented reality (AR) technology, a new interdisciplinary frontier. As a new generation of technology, MR has attracted great attention of clinicians in recent years. The emergence of MR will bring about revolutionary changes in medical education training, medical research, medical communication, and clinical treatment. At present, MR technology has become the popular frontline information technology for medical applications. With the popularization of digital technology in the medical field, the development prospects of MR are inestimable. The purpose of this review article is to introduce the application of MR technology in the medical field and prospect its trend in the future.

Application of the Guiding Template Designed by Three-dimensional Printing Data for the Insertion of Sacroiliac Screws: a New Clinical Technique.

This study is aimed to explore the clinical application of the guiding template designed by three-dimensional printing data for the insertion of sacroiliac screws. A retrospective study of 7 cases (from July 2016 to December 2016), in which the guiding template printed by the threedimensional printing technique was used for the insertion of sacroiliac screws of patients with posterior ring injuries of pelvis, was performed. Totally, 4 males and 3 females were included in template group, aged from 38 to 65 years old (mean 50.86±8.90). Of them, 5 had sacral fractures (3 with Denis type I and 2 with type II) and 2 the separation of sacroiliac joint. Guiding templates were firstly made by the three-dimensional printing technique based on the pre-operative CT data. Surgical operations for the stabilization of pelvic ring by applying the guiding templates were carried out. A group of 8 patients with sacroiliac injuries treated by percutaneous sacroiliac screws were analyzed as a control group retrospectively. The time of each screw insertion, volume of intra-operative blood loss, and the exposure to X ray were analyzed and the Matta's radiological criteria were used to evaluate the reduction quality. The Majeed score was used to evaluate postoperative living quality. The visual analogue scale (VAS) was applied at different time points to judge pain relief of coccydynia. All the 7 patients in the template group were closely followed up radiographically and clinically for 14 to 20 months, mean (16.57±2.44) months. Totally 9 sacroiliac screws for the S1 and S2 vertebra were inserted in the 7 patients. The time length for each screw insertion ranged from 450 to 870 s, mean (690.56±135.68) s, and the number of times of exposure to X ray were 4 to 8, mean (5.78±1.20). The intra-operative blood loss ranged from 45 to 120 mL, mean (75±23.32) mL. According to Matta's radiology criteria, the fracture and dislocation reduction were excellent in 6 cases and good in 1. The pre-operative VAS score ranged from 5.2 to 8.1, mean (7.13±1.00). The average one-week/six-month post-operative VAS was (5.33±0.78) and (1.33±0.66), respectively (P<0.05 when compared with pre-operative VAS). The 12-month postoperative Majeed score ranged from 86 to 92, mean (90.29±2.21). The three-dimensional printed guiding template for sacroiliac screw insertion, which could significantly shorten the operation time, provide a satisfied outcome of the stabilization of the pelvic ring, and protect doctors and patients from X-ray exposure, might be a practical and valuable new clinical technique.

Epigenetic silencing of SFRP5 promotes the metastasis and invasion of chondrosarcoma by expression inhibition and Wnt signaling pathway activation.

BACKGROUD/AIMS: Abnormal activation of the Wnt/ß-catenin signaling, which may be antagonized by the members of secreted frizzled-related proteins family (SFRPs), is implicated in tumor occurrence and development. However, the function of SFRP5 relating to Wnt/ß-catenin pathway in chondrosarcoma is not clear yet. This study was undertaken to investigate the potential role of SFRP5 promoter methylation in chondrosarcoma metastasis and invasion through activating canonical Wnt signaling pathway. METHODS AND RESULTS: The results demonstrated that SFRP5 promoter was hypermethylated and SFRP5 expression was significantly reduced in chondrosarcoma cell lines at the mRNA and protein levels. The canonical Wnt/ß-catenin signaling was observably activated with ß-catenin stabilization by dephosphorylation and translocation into the nuclear. 5-Aza-2'-deoxycytidine (5-Aza-dC), the DNA methyltransferase inhibitor, significantly inhibited the proliferation of chondrosarcoma cells by cell cycle arrest through repressing the methylation of SFRP5 and promoting its expression. Both 5-Aza-dC treatment and SFRP5 overexpression could significantly inhibited the metastasis and invasion of chondrosarcoma cells by inactivating Wnt/ß-catenin signaling pathway and promoting chondrosarcoma cells mesenchymal-epithelial transition (MET). 5-Aza-dC also inhibited the xenograft growth and lung metastasis of chondrosarcoma cells in vivo via suppressing SFRP5 promotor methylation, inactivating Wnt/ß-catenin pathway and inducing epithelial markers expression. CONCLUSION: All of our results revealed the epigenetic silencing of SFRP5 by promoter methylation plays pivotal roles in chondrosarcoma development and metastasis through SFRP5/Wnt/ß-catenin signaling axis. Modulation of their levels may serve as potential targets and diagnostic tools for novel therapeutic strategies of chondrosarcoma.

Cooperative Assembly of a Peptide Gelator and Silk Fibroin Afford an Injectable Hydrogel for Tissue Engineering.

Silk fibroin (SF) from Bombyx mori has received increasing interest in biomedical fields, because of its slow biodegradability, good biocompatibility, and low immunogenicity. Although SF-based hydrogels have been studied intensively as a potential matrix for tissue engineering, weak gelation performance and low mechanical strength are major limitations that hamper their widespread applicability. Therefore, searching for new strategies to improve the SF gelation property is highly desirable in tissue engineering research. Herein, we report a facile approach to induce rapid gelation of SF by a small peptide gelator (e.g., NapFF). Following the simple mixing of SF and NapFF in water, a stable hydrogel of SF was obtained in a short time period at physiological pH, and the minimum gelation concentration of SF can reach as low as 0.1%. In this process of gelation, NapFF not only can behave itself as a gelator for supramolecular self-assembly, but also can trigger the conformational transition of the SF molecule from random coil to ß-sheet structure via hydrophobic and hydrogen-bonding interactions. More importantly, for the generation of a scaffold with favorable cell-surface interactions, a new peptide gelator (NapFFRGD) with Arg-Gly-Asp (RGD) domain was applied to functionalize SF hydrogel with improved bioactivity for cell adhesion and growth. Following encapsulating the vascular endothelial growth factor (VEGF), the SF gel was subcutaneously injected in mice, and served as an effective matrix to trigger the generation of new blood capillaries in vivo.

TRAIL-R1 as a novel surface marker for circulating giant cell tumor of bone.

Giant cell tumor of bone (GCT), which frequently occurs in the patients' spine, is relatively prevalent in Chinese population. A group of GCT invades into vessels and appears to be circulating tumor cells (CTCs) responsible for the distal metastasis of the primary tumor. So far the cell surface markers of GCT have not been determined. In the current study, we aimed to identify a novel CTC marker with higher specificity in GCT. TRAIL-R1+ cells were purified from GCT cell lines. The TRAIL-R1+ cells were compared with total GCT cells for tumor sphere formation, chemo-resistance, tumor formation in nude mice, and frequency of developing distal metastases. We found that TRAIL-R1+ GCT cells appeared to be highly enriched for CTCs in GCT. Compared to total GCT cells, TRAIL-R1+ GCT cells generated significantly more tumor spheres in culture, were higher chemo-resistant, and had a higher frequency of being detected in the circulation after subcutaneous transplantation as well as development of distal metastases. Thus, we conclude that TRAIL-R1+ may be a novel CTC marker in GCT. Selective elimination of TRAIL-R1+ GCT cells may improve the current GCT therapy.

In vitro effect of microRNA-107 targeting Dkk-1 by regulation of Wnt/ß-catenin signaling pathway in osteosarcoma.

BACKGROUND: The aim of the study was to explore the effects of microRNA-107 (miR-107) by targeting Dkk-1 on osteosarcoma (OS) via the Wnt/ß-catenin signaling pathway. METHODS: OS and adjacent tissues were collected from 67 patients diagnosed with OS. Expressions of miR-107, Dkk-1, LRP5, ß-catenin, and c-Myc were detected by the quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. The dual-luciferase reporter gene assay was performed to observe the relationship between miR-107 and Dkk-1.Transfected cells were divided into different investigating groups designated as Inhibitor, Mimic, siRNA, Inhibitor + siRNA, negative control (NC), and blank groups. qRT-PCR and Western blotting were used to detect expressions of miR-107, Dkk-1, ß-catenin, Bcl-2, c-Myc, Caspase-3, and PARP. Cell counting kit-8 (CCK-8), flow cytometry (FCM), colony-formation efficiency (CFE), and subcutaneous tumorigenicity assays were all utilized for to determine cell proliferation, apoptosis, colony-forming, and tumorigenic abilities. RESULTS: Dkk-1 is the target gene of miR-107. Decreased expressions of miR-107, LRP5, ß-catenin, and c-Myc, and increased expressions of Dkk-1 were found in OS tissues. The Mimic and siRNA groups exhibited decreased proliferation rates, colony-forming abilities, and tumorigenicity and increased apoptosis rates, whereas the inhibitor group showed opposite trends when compared to the blank group. On the other hand, expressions of miR-107, LRP5, ß-catenin, c-Myc, Caspase-3, and PARP were all elevated in the mimic group, whereas expressions of Dkk-1 and Bcl-2 were reduced; opposite trends were observed in the inhibitor group. CONCLUSION: We conclude that miR-107 is likely to inhibit the occurrence and development of OS by down-regulating Dkk-1 via the Wnt/ß-catenin signaling pathway, providing us with a new therapeutic target for the treatment of OS.

Drp1 mediates compression-induced programmed necrosis of rat nucleus pulposus cells by promoting mitochondrial translocation of p53 and nuclear translocation of AIF.

Compression-induced programmed cell death of nucleus pulposus (NP) cells is an important contributor to intervertebral disc degeneration (IDD). Dynamin-related protein 1 (Drp1), a crucial mitochondrial fission protein, triggers programmed necrosis upon cellular injury. However, limited information is available about the role of Drp1 in compression-induced programmed necrosis of NP cells. In the present study, we found that compression resulted in upregulation and mitochondrial translocation of Drp1. Inhibition of Drp1 by siRNA or mitochondrial division inhibitor 1 (mdivi-1) effectively prevented the programmed necrosis of NP cells treated with compression. Furthermore, Drp1 promoted mitochondrial translocation of p53 and nuclear translocation of apoptosis-inducing factor (AIF) in compression-treated NP cells. Inhibition of p53 mitochondrial translocation by pifithrin-µ (PFT-µ) and silencing of AIF expression by siRNA significantly alleviated compression-induced NP cell programmed necrosis. These data indicates that Drp1 mediates compression-induced programmed necrosis of NP cells by promoting mitochondrial translocation of p53 and nuclear translocation of AIF.

Novel application of vacuum sealing drainage with continuous irrigation of potassium permanganate for managing infective wounds of gas gangrene.

Traumatic gas gangrene is a fatal infection mainly caused by Clostridium perfringens. It is a challenge to manage gas gangrene in open wounds and control infection after debridement or amputation. The aim of the present study was to use vacuum sealing drainage (VSD) with continuous irrigation of potassium permanganate to manage infective wounds of gas gangrene and observe its clinical efficacy. A total of 48 patients with open traumatic gas gangrene infection were included in this study. Amputations were done for 27 patients, and limb salvage procedures were performed for the others. After amputation or aggressive debridement, the VSD system, including polyvinyl alcohol (PVA) foam dressing and polyurethane (PU) film, with continuous irrigation of 1:5000 potassium permanganate solutions, was applied to the wounds. During the follow-up, all the patients healed without recurrence within 8-18 months. There were four complications. Cardiac arrest during amputation surgery occurred in one patient who suffered from severe septic shock. Emergent resuscitation was performed and the patient returned to stable condition. One patient suffered from mixed infection of Staphylococcal aureus, and a second-stage debridement was performed. One patient suffered from severe pain of the limb after the debridement. Exploratory operation was done and the possible reason was trauma of a local peripheral nerve. Three cases of crush syndrome had dialysis treatment for concomitant renal failure. In conclusion, VSD can convert open wound to closed wound, and evacuate necrotic tissues. Furthermore, potassium permanganate solutions help eliminate anaerobic microenvironment and achieve good therapeutic effect on gas gangrene and mixed infection. VSD with continuous irrigation of potassium permanganate is a novel, simple and feasible alternative for severe traumatic open wounds with gas gangrene infection.

Initial CT-guided percutaneous biopsy of vertebral lesions: Evaluation of its diagnostic accuracy and clinical value.

This study aimed to examine the diagnostic accuracy and clinical efficacy of initial CT-guided percutaneous biopsy of the vertebral lesions. A total of 305 percutaneous biopsies of the vertebral lesions were performed under either CT guidance (n=127) or C-arm guidance (n=178). The diagnostic accuracy rate was evaluated by comparing the histopathological diagnosis with the ultimate diagnosis. The histopathological diagnosis was consistent with the ultimate diagnosis in 108 (85.0%, 108/127) cases of CT-guided biopsy and in 135 (75.8%, 135/178) cases of C-arm guided biopsy and there was a significant difference. The accuracy of diagnosis based on biopsies varied with different diseases, including primary benign or malignant tumors, metastatic tumors, inflammatory lesions and fractures. A second biopsy or further examinations were required for patients with negative result obtained in the initial biopsy. The complication rate was 3.1% (4/127) in CT-guided biopsy and 7.3% (13/178) in C-arm guided biopsy. In conclusion, CT-guided percutaneous biopsy is an accurate and safe technique for biopsy of the vertebral lesions.

Controlled chondrogenesis from adipose-derived stem cells by recombinant transforming growth factor-ß3 fusion protein in peptide scaffolds.

Adipose-derived stem cells (ADSCs) are promising for cartilage repair due to their easy accessibility and chondrogenic potential. Although chondrogenesis of transforming growth factor-ß (TGF-ß) mediated mesenchymal stem cells (MSCs) is well established in vitro, clinical tissue engineering requires effective and controlled delivery of TGF-ß in vivo. In this work, a self-assembled peptide scaffold was employed to construct cartilages in vivo through the chondrogenesis from ADSCs controlled by recombinant fusion protein LAP-MMP-mTGF-ß3 that was transfected by lentiviral vectors. During this course, the addition of matrix metalloproteinases (MMPs) can trigger the release of mTGF-ß3 from the recombinant fusion protein of LAP-MMP-mTGF-ß3 in the combined scaffolds, thus stimulating the differentiation of ADSCs into chondrogenesis. The specific expression of cartilage genes was analyzed by real-time polymerase chain reaction and Western blot. The expression of chondrocytic markers was obviously upregulated to a higher level compared to the one by commonly used TGF-ß3 alone. After 3 weeks of in vitro culturing, the hybrids with differentiated chondrogenesis were then injected subcutaneously into nude mice and retrieved after 4 weeks of culturing in vivo. Histological analysis also confirmed that the recombinant fusion protein was more effective for the formation of cartilage matrix than the cases either with TGF-ß3 alone or without LAP-MMP-mTGF-ß3 (P<0.05). This study demonstrates that controlled local delivery of the LAP-MMP-mTGF-ß3 constructs can accelerate differentiation of ADSCs into the cartilage in vivo, which indicates the great potential of this hybrid in rapid therapy of osteoarthritis.

Effect of microRNA-101 on proliferation and apoptosis of human osteosarcoma cells by targeting mTOR.

Studies have proved that microRNA-101 (miR-101) functions as a tumor suppressor and is associated with growth and apoptosis of various human cancers. However, the role of miR-101 in osteosarcoma and the possible mechanism by which miR-101 affects the tumor growth and apoptosis have not been fully elucidated. In this study, we found that the expression of miR-101 was down-regulated in osteosarcoma tissues and Saos-2 cell line as compared with that in adjacent non-neoplastic bone tissues and the osteoblastic cell line. To better characterize the role of miR-101 in osteosarcoma, we used a gain-of-function analysis by transfecting human osteosarcoma cell line Saos-2 with chemically synthesized miR-101 mimics. The results showed that overexpression of miR-101 inhibited the proliferation and promoted the apoptosis of Saos-2 cells. Meanwhile, bioinformatic analysis demonstrated that mTOR gene was a direct target of miR-101. Overexpression of miR-101 significantly decreased the expression of mTOR at both mRNA and protein levels in Saos-2 cells, consequently inhibiting Saos-2 cells proliferation and promoting cells apoptosis in an mTOR-dependent manner. Taken together, these data suggest that miR-101 may act as a tumor suppressor, which is commonly downregulated in both osteosarcoma tissues and cells. mTOR plays an important role in mediating miR-101 dependent biological functions in osteosarcoma. Reintroduction of miR-101 may be a novel therapeutic strategy by down-regulating mTOR expression.

Promotion of chondrogenesis of marrow stromal stem cells by TGF-ß3 fusion protein in vivo. [corrected].

The purpose of this study was to investigate the repair of the osteoarthritis(OA)-induced cartilage injury by transfecting the new TGF-ß3 fusion protein (LAP-MMP-mTGF-ß3) with targeted therapy function into the bone marrow-derived mesenchymal stem cells (MSCs) in rats. The recombinant of pIRES-EGFP-MMP was constructed by combination of DNA encoding MMP enzyme cutting site and eukaryotic expression vector pIRES-EGFP. LAP and mTGF-ß3 fragments were obtained from rat embryos by RT-PCR and inserted into the upstream and downstream of MMP from pIRES-EGFP-MMP respectively, so as to construct the recombinant plasmid of pIRES-EGFP-LAP-MMP-mTGF-ß3. pIRES-EGFP-LAP-MMP-mTGF-ß3 was transfected into rat MSCs. The genetically modified MSCs were cultured in medium with MMP-1 or not. The transfected MSCs were transplanted in the rat OA models. The OA animal models were surgically induced by anterior cruciate ligament transaction (ACLT). The pathological changes were observed under a microscope by HE staining, Alcian blue, Safranin-fast Green and graded by Mankin's scale. pIRES-EGFP-LAP-MMP-mTGF-ß3 was successfully constructed by means of enzyme cutting and sequencing, and the mTGF-ß3 fusion protein (39 kD) was certified by Western blotting. Those genetically modified MSCs could differentiate into chondrocytes induced by MMP and secrete the relevant-matrix. The transfected MSCs could promote chondrogenesis and matrix production in rat OA models in vivo. It was concluded that a new fusion protein LAP-MMP-mTGF-ß3 was constructed successfully by gene engineering, and could be used to repair the OA-induced cartilage injury.

Construction of self-assembled cartilage tissue from bone marrow mesenchymal stem cells induced by hypoxia combined with GDF-5.

It is widely known that hypoxia can promote chondrogenesis of human bone marrow derived mesenchymal stem cells (hMSCs) in monolayer cultures. However, the direct impact of oxygen tension on hMSC differentiation in three-dimensional cultures is still unknown. This research was designed to observe the direct impact of oxygen tension on the ability of hMSCs to "self assemble" into tissue-engineered cartilage constructs. hMSCs were cultured in chondrogenic medium (CM) containing 100 ng/mL growth differentiation factor 5 (GDF-5) at 5% (hypoxia) and 21% (normoxia) O2 levels in monolayer cultures for 3 weeks. After differentiation, the cells were digested and employed in a self-assembly process to produce tissue-engineered constructs under hypoxic and normoxic conditions in vitro. The aggrecan and type II collagen expression, and type X collagen in the self-assembled constructs were assessed by using immunofluorescent and immunochemical staining respectively. The methods of dimethylmethylene blue (DMMB), hydroxyproline and PicoGreen were used to measure the total collagen content, glycosaminoglycan (GAG) content and the number of viable cells in each construct, respectively. The expression of type II collagen and aggrecan under hypoxic conditions was increased significantly as compared with that under normoxic conditions. In contrast, type X collagen expression was down-regulated in the hypoxic group. Moreover, the constructs in hypoxic group showed more significantly increased total collagen and GAG than in normoxic group, which were more close to those of the natural cartilage. These findings demonstrated that hypoxia enhanced chondrogenesis of in vitro, scaffold-free, tissue-engineered constructs generated using hMSCs induced by GDF-5. In hypoxic environments, the self-assembled constructs have a Thistological appearance and biochemical parameters similar to those of the natural cartilage.

Interactive effect of bisphenol A (BPA) exposure with -22G/C polymorphism in LOX gene on the risk of osteosarcoma.

BACKGROUND: Osteosarcomas have many established risk factors, both genetic and environmental, but by themselves these explain only part of the total cancer incidence. Bisphenol A (BPA) is an environmental estrogen associated with risk of several kinds of tumour. The lysyl oxidase gene (LOX) may also contribute to risk of tumours including osteosarcomas. Here, we investigated possible interactions of BPA and a LOX polymorphism on the risk of osteosarcoma. METHOD: The present hospital-based case-control study included 106 cancer patients and 112 controls from a Chinese population. Internal burden of BPA exposure was assessed using high-performance liquid chromatography-mass spectrometry (HPLC-MS) method. Genotypes were determined using PCR-RFLP methods. RESULTS: Compared with those in low BPA exposure group, subjects with BPA more than or equal to median value had significant increased risk of osteosarcoma among subjects who carried GC or CC genotypes. A significant interaction with BPA level and the -22 G/C polymorphism was observed for osteosarcoma overall, osteosarcoma affecting knee and osteosarcoma affecting hip, as P(forinteraction) = 0.036 for osteosarcoma overall; P(forinteraction) = 0.024 for osteosarcoma affecting knee; and P(forinteraction) = 0.017 for osteosarcoma affecting hip. CONCLUSIONS: The results suggest that BPA exposure interacts with the -22 G/C polymorphism of the LOX gene to increase the risk of osteosarcoma.