Trapezoidal Osteotomy for Treatment of Long-Standing Nonunion of Lateral Humeral Condyle Fracture With Cubitus Valgus Deformity.

PURPOSE: Long-term nonunion of the lateral humerus condyle fracture may lead to progressive cubitus valgus, elbow pain and instability, and secondary ulnar neuritis. A number of techniques of osteotomy are available for correction, but each has its disadvantages. The aim of this study was to present a technique of medial trapezoidal osteotomy for correcting nonunion of the lateral humeral condyle with an elbow valgus deformity >20°. METHODS: Eight patients (mean age, 7.5 years) with cubitus valgus, after neglected nonunion of a lateral humeral condyle fracture of greater than 2 years duration, were treated with trapezoidal combined osteotomy. The mean interval from the lateral condylar fracture to surgery was 3.1 years. The osteotomy lines were marked on the bone with a template made before surgery. The lateral condyle and osteotomy site were fixed with K-wires, and the elbow joint was immobilized in a plaster brace. Pre- and postoperative carrying angles, range of motion, elbow function, and ulnar nerve neuropathy were analyzed. RESULTS: The mean follow-up was 5.9 years. Union of the lateral condyle was achieved in all patients; 3 healed at 8 weeks, 2 healed at 9 weeks, 2 healed at 10 weeks, and 1 healed at 12 weeks. The mean carrying angle decreased from 30.1° before surgery to 5.8° after surgery. The surgery did not reduce the range of motion at the elbow. According to the Mayo Elbow Performance Score, 6 patients had excellent elbow function, and 2 had good elbow function at the last follow-up. All preoperative ulnar nerve symptoms resolved. One patient had a mild surgical site infection. No other complications occurred. CONCLUSIONS: Medial trapezoidal osteotomy appears to be an effective method for treating nonunion of lateral humeral epicondyle fracture with cubitus valgus deformity. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic V.

A novel method of lateral closing wedge osteotomy for cubitus varus deformity in children.

BACKGROUND: Humeral osteotomy is the best method for treatment of severe cubitus varus in children. Many osteotomy methods have been developed in the past. In this study, we describe a novel corrective technique by applying the principles described by Paley involving lateral osteotomy using Kirschner wires (K-wires). Vertices of the osteotomy should be located at the center of rotation of angulation. The anatomical and mechanical axes can be corrected with precision. PATIENTS AND METHODS: In this retrospective study, 21 patients (17 male, 4 female) who fulfilled the study criteria and underwent lateral closing osteotomy for cubitus varus deformity from July 2015 to October 2017 were included into the study. The osteotomy line of all patients was designed according to Paley's principles. An isosceles triangle template was made according to the design preoperatively. The lateral osteotomy was made with the assistance of C-arm radiographs. The osteotomy was fixed by K-wires laterally. Patients were followed up, and elbows were evaluated by radiography and using the Mayo Elbow Performance Index (MEPI) score. RESULTS: The mean correction angle obtained was 32.33°±2.83°. According to the MEPI score assessment, 19 of the 21 patients had an excellent outcome and two had a good outcome. Two patients complained of conspicuous scars; however, no further cosmetic surgery was performed. The range of motion was 135.0° preoperatively and 133.7° postoperatively, showing no significant difference (p = 0.326). None showed evidence of neurovascular injury or complained of prominence of the lateral humerus. CONCLUSION: Paley's principles for correcting cubitus varus deformity in children are effective and reliable for treating such a condition. LEVEL OF EVIDENCE: Therapeutic IV.

Is Femoral Neck System a Valid Alternative for the Treatment of Displaced Femoral Neck Fractures in Adolescents? A Comparative Study of Femoral Neck System versus Cannulated Compression Screw.

Background and Objectives: The femoral neck system (FNS) is a new minimally invasive internal fixation system for femoral neck fractures (FNFs), but its use has not been reported in adolescents. The aim of this study was to compare the clinical and radiographic outcomes of displaced FNF in adolescents treated with FNS or a cannulated compression screw (CCS). Materials and Methods: A retrospective study of 58 consecutive patients with displaced FNF treated surgically was performed; overall, 28 patients underwent FNS and 30 CCS fixation. Sex, age at injury, type of fracture, associated lesions, duration of surgery, radiation exposure, and blood loss were collected from the hospital database. The clinical and radiographic results, as well as complications, were recorded and compared. Results: The patients were followed up for 16.4 ± 3.1 months on average after index surgery (range, 12 to 24). Consolidation time among patients treated with FNS was significantly lower than those managed by CCS (p = 0.000). The functional scores of patients treated with FNS were significantly higher than those managed by CCS (p = 0.030). Unplanned hardware removal in patients treated with FNS was significantly lower than in those managed by CCS (p = 0.024). Conclusions: FNS has a lower complication rate and better functional outcome than CCS. It may be a good alternative to treat femoral neck fractures in adolescents.

Use of a radiopaque localizer grid and methylene blue staining as an aid to reduce radiation exposure.

BACKGROUND: Localization of small femur lesions for resection can be challenging and may be associated with the need for significant fluoroscopic imaging and tissue dissection. This study was performed to evaluate the use of a radiopaque localizer grid along with methylene blue staining for resection of small femur lesions in children, and to determine the effectiveness of this effectiveness at reducing radiation exposure and tissue injury. MATERIAL AND METHODS: A radiopaque localizer grid was used to identify the body surface site of bone lesions, and then 0.02-0.03 mL of methylene blue was injected into the bone lesions. After skin incision, the blue bone tissue was found and complete lesion resection performed. RESULTS: A radiopaque localizer grid was utilized to plan the point of entry for lesion resection. The average operation time was shorter, and the C-arm was used less frequently, and the incision length was shorter in the grid and methylene blue group compared with the control group. CONCLUSION: A radiopaque localizer grid is a simple and practical device for efficient localization of the skin entry site, and methylene blue accurately pinpoints bone lesions, reducing radiation exposure and tissue injury.

Modified osteotomy for treatment of forearm deformities (Masada IIb) in hereditary multiple osteochondromas: a retrospective review.

PURPOSE: Approximately 30% of patients with hereditary multiple osteochondromas (HMO) have forearm deformity and dysfunction. The aim of this retrospective study was to review our experience with the surgical treatment of children with HMO and Masada IIb forearm deformities. METHODS: Data of eight children treated for HMO Masada IIb forearm deformity at our hospital between 2015 and 2019 were collected from the hospital records and retrospectively reviewed. All patients underwent ulnar lengthening by distraction osteogenesis using either the Orthofix or Ilizarov external fixator. Range of movements at the elbow and wrist joints, and forearm supination/pronation, before and after the operation were recorded. Radiographs were evaluated by the Fogel method, and wrist joint function by the Krimmer method. RESULTS: Follow-up radiographs showed significant improvement in relative ulnar shortening after treatment (pre-operative 9.23 ± 5.21 mm; post-operative 0.33 ± 4.13 mm). Changes in radial articular angle (pre-operative 33.55° ± 3.88° to 32.78° ± 6.57°) and carpal slip (pre-operative 45.00% ± 19.09%; post-operative 43.13% ± 16.68%) were not significant. Elbow flexion and extension, wrist flexion and extension, ulnar and radial deviation at wrist, and forearm rotation were significantly improved after surgery. Wrist function was graded as excellent in seven patients and as good in one patient. One patient treated with the Ilizarov external fixator had poor radial head reduction. CONCLUSION: Ulnar lengthening with distraction osteogenesis is an effective treatment for HMO Masada IIb deformities. The optimum site for ulnar osteotomy appears to be at the proximal one-third to one-fourth of the ulna.

Retrospective analysis of traumatic triradiate cartilage injury in children.

BACKGROUND: To summarize and analyze the epidemiological characteristics, treatment and corresponding curative effect of triradiate cartilage injury(TCI) in children after trauma, to provide a theoretical basis for early diagnosis and improvement of treatment. METHODS: The TCI was classified according to Bucholz classification, and the final curative effect was evaluated with Harris Hip Score and imaging examination during follow-up. Finally, a comprehensive analysis was made by reviewing the cases in the literature combined with the patients in our hospital. RESULTS: A total of 15 cases (18 hips) of triradiate cartilage injuries were collected in our hospital. There was 1 hip with type I injury, nine hips with type II injury, two hips with type IV injury, one hip with type V injury and five hips with type VI injury. Among the 12 cases with complete follow-up, the bone bridge was found in or around the triradiate cartilage in 8 cases, early fusion of triradiate cartilage occurred in 5 patients, 3 cases had hip dysplasia, 4 cases had a subluxation of the femoral head, and HHS was excellent in 8 cases and good in 4 cases. CONCLUSION: The early diagnosis of TCI is still a difficult problem. Conservative treatment is often the first choice. The overall prognosis of acetabular fractures involving triradiate cartilage is poor. The formation of the bone bridge in triradiate cartilage usually indicates the possibility of premature closure, which may lead to severe complications of post-traumatic acetabular dysplasia and subluxation of the femoral head.

Reversibly immortalized human umbilical cord-derived mesenchymal stem cells (UC-MSCs) are responsive to BMP9-induced osteogenic and adipogenic differentiation.

Human mesenchymal stem cells (MSCs) are a heterogeneous subset of nonhematopoietic multipotent stromal stem cells and can differentiate into mesodermal lineage, such as adipocytes, osteocytes, and chondrocytes, as well as ectodermal and endodermal lineages. Human umbilical cord (UC) is one of the most promising sources of MSCs. However, the molecular and cellular characteristics of UC-derived MSCs (UC-MSCs) require extensive investigations, which are hampered by the limited lifespan and the diminished potency over passages. Here, we used the piggyBac transposon-based simian virus 40 T antigen (SV40T) immortalization system and effectively immortalized UC-MSCs, yielding the iUC-MSCs. A vast majority of the immortalized lines are positive for MSC markers but not for hematopoietic markers. The immortalization phenotype of the iUC-MSCs can be effectively reversed by flippase recombinase-induced the removal of SV40T antigen. While possessing long-term proliferation capability, the iUC-MSCs are not tumorigenic in vivo. Upon bone morphogenetic protein 9 (BMP9) stimulation, the iUC-MSC cells effectively differentiate into osteogenic, chondrogenic, and adipogenic lineages both in vitro and in vivo, which is indistinguishable from that of primary UC-MSCs, indicating that the immortalized UC-MSCs possess the characteristics similar to that of their primary counterparts and retain trilineage differentiation potential upon BMP9 stimulation. Therefore, the engineered iUC-MSCs should be a valuable alternative cell source for studying UC-MSC biology and their potential utilities in immunotherapies and regenerative medicine.

The evolving roles of canonical WNT signaling in stem cells and tumorigenesis: implications in targeted cancer therapies.

The canonical WNT/ß-catenin signaling pathway governs a myriad of biological processes underlying the development and maintenance of adult tissue homeostasis, including regulation of stem cell self-renewal, cell proliferation, differentiation, and apoptosis. WNTs are secreted lipid-modified glycoproteins that act as short-range ligands to activate receptor-mediated signaling pathways. The hallmark of the canonical pathway is the activation of ß-catenin-mediated transcriptional activity. Canonical WNTs control the ß-catenin dynamics as the cytoplasmic level of ß-catenin is tightly regulated via phosphorylation by the 'destruction complex', consisting of glycogen synthase kinase 3ß (GSK3ß), casein kinase 1α (CK1α), the scaffold protein AXIN, and the tumor suppressor adenomatous polyposis coli (APC). Aberrant regulation of this signaling cascade is associated with varieties of human diseases, especially cancers. Over the past decade, significant progress has been made in understanding the mechanisms of canonical WNT signaling. In this review, we focus on the current understanding of WNT signaling at the extracellular, cytoplasmic membrane, and intracellular/nuclear levels, including the emerging knowledge of cross-talk with other pathways. Recent progresses in developing novel WNT pathway-targeted therapies will also be reviewed. Thus, this review is intended to serve as a refresher of the current understanding about the physiologic and pathogenic roles of WNT/ß-catenin signaling pathway, and to outline potential therapeutic opportunities by targeting the canonical WNT pathway.

Internal Fixation With Absorbable Rods for the Treatment of Displaced Radial Neck Fractures in Children.

BACKGROUND: The treatment of radial neck fractures with complete displacement or severe displacement and an angle of >30 degrees is controversial. The currently used methods, including the Metaizeau technique, are associated with drawbacks such as imperfect reduction, epiphyseal damage, and delayed functional recovery. To overcome these drawbacks, we used absorbable rod fixation followed by early functional training for the treatment of displaced radial neck fractures in children. METHODS: In this study, 68 patients (age, 4 to 12 y; average, 8.4 y; average angle, 58 degrees; average displacement, 53%) with radial neck fractures with Salter-Harris grades II to IV underwent lateral elbow open reduction and absorbable rod fixation. At 3 weeks postoperatively, the patients' plaster casts were removed, and functional training was started. RESULTS: Anatomic reduction was achieved in all patients. We followed-up 68 patients for 6 months to 4 years (average, 41 mo). No cases of radial nerve injury, radial bone necrosis, myositis ossificans, and postoperative infection were observed. The functional recovery was "excellent" in 43 patients, "good" in 13 patients, "average" in 12 patients, and "bad" in 0 patients, according to the Morrey evaluation standard. CONCLUSION: Open reduction with absorbable rod fixation for the treatment of displaced radial neck fractures in children was feasible and was a choice in children. LEVEL OF EVIDENCE: Therapeutic II.

Visualization of the wrist ganglion capsule by methylene blue staining as an aid for complete resection in children.

PURPOSE: To evaluate the effectiveness of methylene blue staining during ganglion resection in children, to assess ganglion resection and minimize recurrence. METHODS: From August 2007 to March 2011, 36 children with dorsal or volar wrist ganglions with an average size of 2 cm (range, 1-4 cm), including 5 recurrent cases, underwent resection performed with intraoperative methylene blue marking of the cyst wall. RESULTS: We found recurrence in one patient after 2 years; no obvious complications were observed in any patient. CONCLUSIONS: Methylene blue staining of the ganglion during resection may be helpful for achieving complete resection. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic II.

Manipulation and brace fixing for the treatment of congenital clubfoot in newborns and infants.

BACKGROUND: As one of the most common congenital deformities in children, clubfoot has long been a challenge for orthopedic surgeons. This paper describes the experience of our team with manipulation and above-the-knee brace fixation without percutaneous Achilles tenotomy for the treatment of clubfoot in newborns and infants. METHODS: In the orthopedic department of our hospital, 32 infants and newborns (56 feet) with congenital clubfoot underwent manipulation and above-the-knee brace fixation between 2008 and 2012. External rotation brace was used for 1-4 years during the night after deformity correction. Prospective follow-up for a mean duration of 29 months (range, 12-48 months) was carried out. The efficacy of the treatment was assessed by Pirani's scoring system before and after treatment. RESULTS: Fifty-two feet achieved a normal appearance within 3 to 6 months (average, 4.2 months) after treatment. Two patients had skin pressure sores due to improper brace care, but these healed with no scarring after timely treatment. The mean Pirani score 1 year after treatment was 0.21 ± 0.09, whereas it was 4.93 ± 1.02 before treatment (p=0.0078). No patient required treatment with percutaneous Achilles tenotomy. CONCLUSION: The manipulation and brace fixation used in this study offer an effective method for correcting clubfoot deformity in newborns and infants. This treatment can be an alternative choice to percutaneous Achilles tenotomy.

Application direct anterior approach in pediatric femoral head and neck lesions.

BACKGROUND: Femoral neck is one of the high-risk areas for benign tumors and tumor-like lesions. Small range of lesions may also lead to pathological fracture, femoral head necrosis and other serious problems. PURPOSE: To investigate a new minimally invasive surgical approach to resect femoral head and neck lesions in children. PATIENTS AND METHODS: Retrospective study of 20 patients with femoral neck and femoral head lesions from February 2019 to March 2023 in our hospital. Among them, 14 were boys and 6 were girls, 17 were femoral neck lesions and 3 were femoral head lesions. The age of the patients ranged from 3.2 to 12.6 years, with a mean of 7.1 years. The patients were divided into group A and group B according to different surgical approaches; group A used the Smith-Peterson approach, Watson-Jones approach or surgical dislocation approach and group B used the DAA. Intra-operatively, incision length, operative time and blood loss were recorded in both groups. Group A consisted of 1 femoral head lesion and 8 femoral neck lesions, including 5 cases of bone cyst and 4 cases of eosinophilic granuloma. Group B consisted of 2 femoral head lesion and 9 femoral neck lesions. A total of 11 patients with different types of disease were included in group B, including bone cysts (3 cases), aneurysmal bone cysts (1 case), eosinophilic granulomas (6 cases), Kaposi's sarcoma (1 case). RESULTS: The two groups of patients differed in terms of incision length (P < 0.05), operative blood loss (P < 0.05) and operative time (P < 0.05). At 6-48 months post-operatively, there were no significant differences in function and all patients had good hip function. CONCLUSION: The direct anterior approach is effective for resection of paediatric femoral head and neck lesions. It provides clear exposure of the surgical site, minimal trauma and does not compromise the integrity of the anterior musculature. LEVEL OF EVIDENCE: III.

Radial nerve palsy in the newborn combined with congenital radial head dislocation: Case report and literature review.

RATIONALE: Radial nerve palsy in the newborn and congenital radial head dislocation (CRHD) are both rare disorders, and early diagnosis is challenging. We reported a case of an infant with concurrent presence of these 2 diseases and provide a comprehensive review of the relevant literature. The purpose of the study is to share diagnostic and treatment experiences and provide potentially valuable insights. PATIENT CONCERNS: A newborn has both radial nerve palsy and CRHD, characterized by limited wrist and fingers extension but normal flexion, normal shoulder and elbow movement on the affected side, characteristic skin lesions around the elbow, and an "audible click" at the radial head. The patient achieved significant improvement solely through physical therapy and observation. DIAGNOSES: The patient was diagnosed with radial nerve palsy in the newborn combined with CRHD. INTERVENTIONS: The patient received regular physical therapy including joint function training, low-frequency pulse electrical therapy, acupuncture, paraffin treatment, as well as overnight splint immobilization. OUTCOMES: The child could actively extend the wrist to a neutral position and extend all fingers. LESSONS: If a neonate exhibits limited extension in the wrist and fingers, but normal flexion, along with normal shoulder and elbow movement, and is accompanied by skin lesions around the elbow, there should be a high suspicion of radial nerve palsy in the newborn.

Ulnar bone tuberculosis in children: Case report and literature review.

RATIONALE: Tuberculosis of the long tubular bones in children's extremities is infrequent, particularly in the ulna. Early diagnosis poses significant challenges. This report presents a case involving a 2-year-old child with tuberculosis of the ulnar bone, accompanied by a comprehensive review of pertinent literature. The purpose of this study is to share diagnostic and therapeutic experiences and provide potentially valuable insights. PATIENT CONCERNS: In this case, the patient exhibited complete destruction and expansion of the ulnar bone, resulting in a forearm size considerably greater than normal. Concerns were raised about the irreversible deformation of the ulna, the potential for a malignant bone tumor, and its impact on forearm function, potentially endangering the patient's life. DIAGNOSES: The diagnosis was confirmed as tuberculosis of the ulnar bone. INTERVENTIONS: The patient underwent surgery to remove the affected ulnar tissue and received anti-tuberculosis medication. OUTCOMES: Subsequent to treatment, the destruction and expansion of the ulnar bone resolved, with the return of normal ulnar morphology and bone structure. LESSONS: Even in the absence of typical symptoms like fever, weight loss, and loss of appetite, extensive destruction and expansion of a long tubular bone should prompt vigilant consideration of bone tuberculosis.

Liberal surgical laparoscopy reduction for acute intussusception: experience from a tertiary pediatric institute.

The optimal treatment for acute intussusception has not yet been defined. In this study, we explored whether employing a liberal laparoscopic intervention for intussusception could lead to favorable outcomes. We performed a historical control analysis to evaluate the outcomes associated with this liberal surgical management protocol. This liberal surgical management protocol were revised to incorporate a new protocol centered around the laparoscopic approach. In some cases of acute intussusception, liberal laparoscopic exploration and intervention were undertaken without initial hydrostatic or pneumatic reduction. During the study interval, a retrospective review was conducted on a total of 3086 patients. These were categorized into two groups: 1338 cases before May 2019 (pre-protocol group) and 1748 cases after May 2019 (post-protocol group). Surgical intervention rates in the pre-protoco and post-protocol period were 10.2% and 27.4% respectively (odds ratio [OR] = 0.30 [95% CI 0.25-0.37]; p < 0.001). No significant differences were observed in baseline clinical characteristics or demographic features between the two groups. The duration from admission to operation was longer for the pre-protocol group (p = 0.008) than for the post-protocol group. The post-protocol group demonstrated decreases in both intestinal resection (OR = 1.50 [95% CI 0.96-2.35]; p = 0.048) and total recurrent events (OR = 1.27 [95% CI 1.04-1.55]; p = 0.012) compared to the pre-protocol group. Liberal laparoscopic intervention for intussusception may effectively reduce the risk of intestinal resection and total recurrent events, thereby exhibiting promising outcomes for patients with intussusception.

Cross-talk between EGF and BMP9 signalling pathways regulates the osteogenic differentiation of mesenchymal stem cells.

Mesenchymal stem cells (MSCs) are multipotent progenitors, which give rise to several lineages, including bone, cartilage and fat. Epidermal growth factor (EGF) stimulates cell growth, proliferation and differentiation. EGF acts by binding with high affinity to epidermal growth factor receptor (EGFR) on the cell surface and stimulating the intrinsic protein tyrosine kinase activity of its receptor, which initiates a signal transduction cascade causing a variety of biochemical changes within the cell and regulating cell proliferation and differentiation. We have identified BMP9 as one of the most osteogenic BMPs in MSCs. In this study, we investigate if EGF signalling cross-talks with BMP9 and regulates BMP9-induced osteogenic differentiation. We find that EGF potentiates BMP9-induced early and late osteogenic markers of MSCs in vitro, which can be effectively blunted by EGFR inhibitors Gefitinib and Erlotinib or receptor tyrosine kinase inhibitors AG-1478 and AG-494 in a dose- and time-dependent manner. Furthermore, EGF significantly augments BMP9-induced bone formation in the cultured mouse foetal limb explants. In vivo stem cell implantation experiment reveals that exogenous expression of EGF in MSCs can effectively potentiate BMP9-induced ectopic bone formation, yielding larger and more mature bone masses. Interestingly, we find that, while EGF can induce BMP9 expression in MSCs, EGFR expression is directly up-regulated by BMP9 through Smad1/5/8 signalling pathway. Thus, the cross-talk between EGF and BMP9 signalling pathways in MSCs may underline their important roles in regulating osteogenic differentiation. Harnessing the synergy between BMP9 and EGF should be beneficial for enhancing osteogenesis in regenerative medicine.

Inhibition of histone deacetylases potentiates BMP9-induced osteogenic signaling in mouse mesenchymal stem cells.

BACKGROUND/AIMS: We have demonstrated that bone morphogenetic protein 9 (BMP9) is one of the most potent BMPs in regulating osteoblast differentiation of mesenchymal stem cells (MSCs) although the molecular mechanism underlying BMP9-induced osteogenesis remains to be fully elucidated. It is known that epigenetic regulations play an important role in regulating the stem cell potency and lineage commitment. Here, we investigate if the inhibition of histone deacetylases (Hdacs) affects BMP9-induced osteogenic differentiation of MSCs. METHODS: Using the Hdac inhibitor trichostatin A (TSA), we assess that TSA enhances BMP9-mediated osteogenic markers and matrix mineralization in MSCs, and bone formation in mouse embryonic limb explants. RESULTS: We find that the endogenous expression of most of the 11 Hdacs is readily detectable in MSCs. BMP9 is shown to induce most Hdacs in MSCs. We demonstrate that TSA potentiates BMP9-induced early osteogenic marker alkaline phosphatase (ALP) activity in MSCs, as well as late osteogenic markers osteopontin (OPN) and osteocalcin (OCN) and matrix mineralization. Fetal limb explant culture studies reveal that TSA potentiates BMP9-induced endochondral bone formation, possibly by expanding hypertrophic chondrocyte zone of growth plate. CONCLUSION: Our findings strongly suggest histone deacetylases may play an important role in fine-tuning BMP9-mediated osteogenic signaling through a negative feedback network in MSCs. Thus, Hdac inhibitors may be used as novel therapeutics for bone fracture healing.

Destabilization of heterologous proteins mediated by the GSK3ß phosphorylation domain of the ß-catenin protein.

BACKGROUND AND AIMS: Wnt/ß-catenin signaling plays important roles in development and cellular processes. The hallmark of canonical Wnt signaling activation is the stabilization of ß-catenin protein in cytoplasm and/or nucleus. The stability of ß-catenin is the key to its biological functions and is controlled by the phosphorylation of its amino-terminal degradation domain. Aberrant activation of ß-catenin signaling has been implicated in the development of human cancers. It has been recently suggested that GSK3ßmay play an essential role in regulating global protein turnover. Here, we investigate if the GSK3ß phosphorylation site-containing degradation domain of ß-catenin is sufficient to destabilize heterologous proteins. METHODS AND RESULTS: We engineer chimeric proteins by fusing ß-catenin degradation domain at the N- and/or C-termini of the enhanced green fluorescent protein (eGFP). In both transient and stable expression experiments, the chimeric GFP proteins exhibit a significantly decreased stability, which can be effectively antagonized by lithium and Wnt1. An activating mutation in the destruction domain significantly stabilizes the fusion protein. Furthermore, GSK3 inhibitor SB-216763 effectively increases the GFP signal of the fusion protein. Conversely, the inhibition of Wnt signaling with tankyrase inhibitor XAV939 results in a decrease in GFP signal of the fusion proteins, while these small molecules have no significant effects on the mutant destruction domain-GFP fusion protein. CONCLUSION: Our findings strongly suggest that the ß-catenin degradation domain may be sufficient to destabilize heterologous proteins in Wnt signaling-dependent manner. It is conceivable that the chimeric GFP proteins may be used as a functional reporter to measure the dynamic status of ß-catenin signaling, and to identify potential anticancer drugs that target ß-catenin signaling.

The E-F hand calcium-binding protein S100A4 regulates the proliferation, survival and differentiation potential of human osteosarcoma cells.

BACKGROUND/AIMS: Osteosarcoma (OS) is the most common primary bone malignancy in children and young adults. Molecular mechanisms underlying the pathogenesis of OS remain to be fully understood. Several members of the E-F hand calcium-binding S100 protein family are differentially expressed in human cancers. We previously showed that S100A6 is highly expressed in OS tumors. In this study, we investigated the role of S100A4 in regulating OS proliferation and osteogenic differentiation. METHODS/RESULTS: Endogenous S100 expression was examined by semi-quantitative PCR in human OS lines. Adenoviral vector-mediated overexpression and RNAi knockdown of S100A4 were used to assess S100A4's effects on cell proliferation, migration and invasion and osteogenic differentiation. Apoptosis was assessed by using anti-caspase-3 immunostaining and flow cytometry with annexin V staining. Early osteogenic marker alkaline phosphatase (ALP) and late markers osteocalcin (OCN) and osteopontin (OPN) were assessed to determine the status of osteogenic differentiation. We found that S100A4 was elevated in metastatic MG63.2 cells. S100A4 knockdown inhibited cell proliferation, prolonged cell doubling time, and induced significant apoptosis. Silencing S100A4 expression in OS cells delayed cell wounding closure and diminished the numbers of migrated OS cells in transwell invasion assay. Furthermore, silencing S100A4 expression stimulated ALP activity, as well as late markers OPN and OCN, in both OS cells and mesenchymal stem cells. CONCLUSION: Our results strongly suggest that S100A4 may promote OS tumor growth by regulating the cell cycle, reducing apoptosis, and inhibiting osteogenic differentiation. Thus, S100A4 may serve as a marker for tumorigenic potential, as well as a therapeutic target.

Operative versus non-operative treatment for clavicle fracture: a meta-analysis.

PURPOSE: The purpose of this study was to assess the effects of operative and non-operative treatment on clavicle fractures. METHOD: Relevant clinical trials on the operative and non-operative treatment for clavicle fractures were retrieved through searching the databases MEDLINE, Embase, OVID and the Cochrane Central Register of Controlled Trials up to December 2011. The quality of the included studies was assessed by two authors. A meta-analysis was carried out on homogeneous studies. Five studies involving 633 clavicle fractures were included. RESULTS: The differences in nonunion [risk ratio (RR) 0.12, 95 % confidence interval (CI) 0.05-0.29], malunion (RR 0.11, 95 % CI 0.04-0.29) and neurological complications (RR 0.45, 95 % CI 0.25-0.81) were statistically significant between operative and non-operative treatment. There was no statistically significant difference in delayed union (RR 0.78, 95 % CI 0.31-1.95). CONCLUSION: Operative treatment is better than non-operative treatment, but decisions should be made in accordance with specific conditions for clinical application.