A nontoxic strontium nanoparticle that holds the potential to act upon osteocompetent cells: An in vitro and in vivo characterization.

Estrogen deficiency, long-term immobilization, and/or aging are commonly related to bone mass loss, thus increasing the risk of fractures. One option for bone replacement in injuries caused by either traumas or pathologies is the use of orthopedic cement based on polymethylmethacrylate (PMMA). Nevertheless, its reduced bioactivity may induce long-term detachment from the host tissue, resulting in the failure of the implant. In view of this problem, we developed an alternative PMMA-based porous cement (pPMMA) that favors cell invasion and improves osteointegration with better biocompatibility. The cement composition was changed by adding bioactive strontium-nanoparticles that mimic the structure of bone apatite. The nanoparticles were characterized regarding their physical-chemical properties, and their effects on osteoblasts and osteoclast cultures were assessed. Initial in vivo tests were also performed using 16 New Zealand rabbits as animal models, in which the pPMMA-cement containing the strontium nanoparticles were implanted. We showed that the apatite nanoparticles in which 90% of Ca2+ ions were substituted by Sr2+ (NanoSr 90%) upregulated TNAP activity and increased matrix mineralization. Moreover, at the molecular level, NanoSr 90% upregulated the mRNA expression levels of, Sp7, and OCN. Runx2 was increased at both mRNA and protein levels. In parallel, in vivo tests revealed that pPMMA-cement containing NanoSr 90%, upregulated two markers of bone maturation, OCN and BMP2, as well as the formation of apatite minerals after implantation in the femur of rabbits. The overall data support that strontium nanoparticles hold the potential to up-regulate mineralization in osteoblasts when associated with synthetic biomaterials.

Treatment alternatives and clinical outcomes of bone filling after benign tumour curettage. A systematic review.

BACKGROUND: Benign and pseudo-neoplastic bone lesions are usually treated by curettage and filling of the cavity. This filling is usually achieved with the use of autologous bone grafts, bone cement, allografts, xenografts, or synthetic bone substitutes. Recently, some authors have suggested that these defects do not require filling for consolidation but the respective rate of complications of each method is not well defined. Therefore, we did a systematic review aiming to answer: (1) Not filling bone cavities after benign bone tumour curettage may increase the rate of fractures? (2) Can the volume of the bone defect in itself be a specific or reliable predictor of fracture? (3) Does the mean functional outcome, recurrence, non-weight bearing time, other postoperative complications or bone consolidation time vary between the methods of filling? PATIENTS AND METHODS: The PubMed (2407 articles) and Latin American and Caribbean Health Sciences Literature (LILACS) (50 articles) databases were reviewed, without restriction considering publication date. After exclusion criteria, 62 articles were selected for data collection. Filling or not filling (UN), methods of filling, fracture rate, bone defect size, mean functional outcome, recurrence, non-weight bearing time, other postoperative complications, consolidation time were the data of interest. RESULTS: The number of patients was 2555 distributed among the different filling methods. Unfilled cavities were associated with higher fracture rate [20/302 (6.62%)] versus 4/189 (2.12%) for allografts, 14/343 (4.08%) for cement filling, 4/247 for autograft (1.62%), and 12/580 (2.07%) for bone substitute. The volume of the bone defect alone is not a specific or reliable predictor of fracture. All filling methods were similar regarding the mean functional outcome, recurrence rate and consolidation time. The bone cement allowed early weight bearing time (mean of weeks): UN: 9.67; autologous bone grafts: 9.8; bone cement: 0.5; allografts: 9.0; synthetic bone substitutes: 9.96. CONCLUSION: Not filling the bone cavity after benign bone tumour curettage is an alternative, but can increase fracture rate, even in small volume bone defects. The use of prophylactic fixation drastically reduces the fracture rate. Filling with cement reduces weight bearing time. There are little differences between the methods used to fill, even compared to not filling the cavity. LEVEL OF EVIDENCE: III; systematic review.

Manual versus semiautomatic segmentation of soft-tissue sarcomas on magnetic resonance imaging: evaluation of similarity and comparison of segmentation times.

OBJECTIVE: To evaluate the degree of similarity between manual and semiautomatic segmentation of soft-tissue sarcomas on magnetic resonance imaging (MRI). MATERIALS AND METHODS: This was a retrospective study of 15 MRI examinations of patients with histopathologically confirmed soft-tissue sarcomas acquired before therapeutic intervention. Manual and semiautomatic segmentations were performed by three radiologists, working independently, using the software 3D Slicer. The Dice similarity coefficient (DSC) and the Hausdorff distance were calculated in order to evaluate the similarity between manual and semiautomatic segmentation. To compare the two modalities in terms of the tumor volumes obtained, we also calculated descriptive statistics and intraclass correlation coefficients (ICCs). RESULTS: In the comparison between manual and semiautomatic segmentation, the DSC values ranged from 0.871 to 0.973. The comparison of the volumes segmented by the two modalities resulted in ICCs between 0.9927 and 0.9990. The DSC values ranged from 0.849 to 0.979 for intraobserver variability and from 0.741 to 0.972 for interobserver variability. There was no significant difference between the semiautomatic and manual modalities in terms of the segmentation times (p > 0.05). CONCLUSION: There appears to be a high degree of similarity between manual and semiautomatic segmentation, with no significant difference between the two modalities in terms of the time required for segmentation.

OBJETIVO: Verificar a similaridade entre as segmentações manual e semiautomática de sarcomas de tecidos moles na ressonância magnética (RM) e a similaridade interobservador e intraobservador entre as segmentações manuais. MATERIAIS E MÉTODOS: Estudo retrospectivo que incluiu 15 exames de RM de pacientes com diagnóstico de sarcoma de tecidos moles realizados antes de intervenções terapêuticas. As segmentações manual e semiautomática foram realizadas por três radiologistas utilizando o software 3D Slicer. O coeficiente de similaridade Dice (CSD) e a distância de Hausdorff foram utilizados para avaliar a similaridade das segmentações. Análise estatística descritiva e coeficiente de correlação intraclasse (CCI) foram realizados para comparar volumes tumorais. RESULTADOS: A comparação dos métodos manual e semiautomático obteve valores de CSD entre 0,871 e 0,973. A comparação dos volumes segmentados pelos dois métodos de segmentação mostrou CCI entre 0,9927 e 0,9990. As análises intraobservador e interobservador obtiveram valores de CSD, respectivamente, de 0,849 a 0,979 e de 0,741 a 0,972. Não houve diferença significativa entre os tempos de segmentação dos métodos semiautomático e manual (p > 0,05). CONCLUSÃO: Houve alta similaridade entre as segmentações de sarcomas de tecidos moles obtidas pelos métodos manual e semiautomático, sem diferença significativa para o tempo despendido para as segmentações.

Yttrium-90 radiosynovectomy in knees and ankles (25 joints in 22 hemophilic patients). Short-term results

ABSTRACT Introduction: The radiosynovectomy (RS) is one treatment option for recurrent hemarthrosis in patients with hemophilia (PWH). A prospective cohort study was designed to evaluate the effects of the RS on the synovial membrane volume in the ankles and knees of PWH and patient characteristics related to the RS outcome. Methods: In a one-year follow-up, 25 joints of 22 PWH who presented 3 bleeds or more in the same joint over the last 6 months (target joints) were subjected to the RS. Two groups were compared: those who retained target joints following the RS and those who did not (less than 3 bleeds/6 months after the RS). The groups were analyzed according to age, hemophilia type/severity, joint, body mass index (BMI), inhibitor and Hemophilia Joint Health Score 2.1 (HJHS). The magnetic resonance images (MRI) of six ankles and six knees were acquired prior to, and 6 months after, the RS. The synovial membrane volume and arthropathy MRI scale were accessed and volumes were compared and correlated with the Yttrium-90 dose injected. Results: Patients with a mean age of 12 years and a mean HJHS of 6.7 (p < 0.05) retained target joints after the RS. The inhibitor, joint, type/severity of disease and BMI showed no significant differences between groups. The synovial membrane volume had a significant reduction after the RS (p = 0.03), but no correlation with the Yttrium-90 dose. In proportion to the synovial membrane volume, doses injected to the ankles were larger than those injected to the knees. Conclusion: The synovial membrane volume is reduced after the RS, regardless of the effective 90Y dose.

Devitalized Autograft Associated with the Vascularized Fibula Graft: Irradiation versus Freezing Methods.

BACKGROUND: Among the alternatives for the management of malignant bone tumors is the "devitalized autograft associated with vascularized fibula graft." The devitalization process is achieved by pasteurization, irradiation, or freezing. The combination of these grafts has been broadly researched for more than 25 years. However, there is no research currently published comparing the various methods or their respective outcomes. METHODS: A retrospective study was compiled of 26 devitalized autografts associated with vascularized fibula performed to limb salvage of malignant bone tumors. They were divided into two groups according to the devitalization method: either freezing (12 procedures) or irradiation (14 procedures). Clinical, radiographic, and scintigraphic results were assessed at least 24 months after surgery. RESULTS: The union rates reached 83.3% in the freezing group and 92.8% in the irradiated group but did not express different outcomes. Scintigraphic viability was observed in all the grafts that achieved radiographic union (Mann-Whitney U-test: p = 0.005). Three patients had nonunion, with only one having no viability in the scintigraphy (Mann-Whitney U-test: p = 0.001). There was no malignant recurrence in the autograft, only in surrounding soft tissues. Local recurrence was statistically higher in larger tumors (Mann-Whitney U-test: p = 0.025). CONCLUSION: Both groups presented similar union rates and are considered safe to devitalize bone graft despite different outcomes observed. The survivor rates observed could be limited by the existence of the techniques.

Yttrium-90 radiosynovectomy in knees and ankles (25 joints in 22 hemophilic patients). Short-term results.

INTRODUCTION: The radiosynovectomy (RS) is one treatment option for recurrent hemarthrosis in patients with hemophilia (PWH). A prospective cohort study was designed to evaluate the effects of the RS on the synovial membrane volume in the ankles and knees of PWH and patient characteristics related to the RS outcome. METHODS: In a one-year follow-up, 25 joints of 22 PWH who presented 3 bleeds or more in the same joint over the last 6 months (target joints) were subjected to the RS. Two groups were compared: those who retained target joints following the RS and those who did not (less than 3 bleeds/6 months after the RS). The groups were analyzed according to age, hemophilia type/severity, joint, body mass index (BMI), inhibitor and Hemophilia Joint Health Score 2.1 (HJHS). The magnetic resonance images (MRI) of six ankles and six knees were acquired prior to, and 6 months after, the RS. The synovial membrane volume and arthropathy MRI scale were accessed and volumes were compared and correlated with the Yttrium-90 dose injected. RESULTS: Patients with a mean age of 12 years and a mean HJHS of 6.7 (p < 0.05) retained target joints after the RS. The inhibitor, joint, type/severity of disease and BMI showed no significant differences between groups. The synovial membrane volume had a significant reduction after the RS (p = 0.03), but no correlation with the Yttrium-90 dose. In proportion to the synovial membrane volume, doses injected to the ankles were larger than those injected to the knees. CONCLUSION: The synovial membrane volume is reduced after the RS, regardless of the effective 90Y dose.

Results of muscle strength and range of motion after total open knee synovectomy.

AIM OF THE STUDY: Scar tissue formation after synovectomy limits range of motion and causes muscle atrophy. The functional results for patients who underwent total open knee synovectomy often included questionnaires, and assessment of muscle strength was lacking in the literature. Therefore, we aimed to identify the strength and range of motion outcomes for patients who underwent total open synovectomy and to compare the results with the contralateral limb and healthy individuals. METHOD: Knee range of motion and muscle strength were assessed in fourteen patients that underwent total (anterior and posterior) open knee synovectomy and were compared with the contralateral limb and with 14 healthy individuals matched by sex, age, height, and weight. RESULTS: The range of motion of flexion decreased 8.4% compared with the contralateral limb (95% CI - 18.9 to - 4.7, p = 0.002) and 9.9% compared with the control group (95% CI 3.9-14.9, p < 0.01). Knee extension strength decreased by 35% compared with the contralateral limb (95% CI 11.1-77.2, p = 0.01) and 37% compared with the control group (95% CI - 112.4-12.1, p = 0.01). CONCLUSION: Despite the aggressiveness of the surgical procedure, the patients achieved satisfactory functional results.

microRNA-138-5p as a Worse Prognosis Biomarker in Pediatric, Adolescent, and Young Adult Osteosarcoma.

Osteosarcoma (OS) is the most common primary malignant bone tumor with two peaks of incidence, in early adolescence and the elderly. Patients affected with this malignancy often present metastatic disease at diagnosis, and despite multimodality therapy, survival has not improved substantially over the past 3 decades. Recently, miR-138-5p, proposed as a crucial intracellular mediator of invasion, has been recognized to target the Rho-associated coiled-coil containing protein kinase 2 (ROCK2). Dysregulation of ROCK1 and ROCK2 was also described in OS, being associated to higher metastasis incidence and worse prognosis. Nonetheless, the specific roles of miR-138-5p in pediatric and young adult OS and its ability to modulate these kinases remain to be established. Thus, in the present study, the expression levels miR-138-5p were evaluated in a consecutive cohort of exclusively pediatric and young adult primary OS samples. In contrast to previous reports that included adult tissues, our results showed upregulation of miR-138-5p associated with reduced event-free survival and relapsed cases. In parallel, ROCK1 mRNA levels were significantly reduced in tumor samples and negatively correlated with miR-138-5p. Similar correlations were observed after studying the profiles of ROCK1 and ROCK2 by immunohistochemistry. Our data present miR-138-5p as a consistent prognostic factor in pediatric and young adult OS, reinforcing its participation in the post-transcriptional regulation of ROCK kinases.

Alterações cromossômicas e periostite / Chromosomal alterations and periostitis

Introdução: A periostite é uma inflamação do periósteo que pode se estender para os tecidos moles adjacentes. Há pouca informação na literatura sobre alterações genéticas nessas lesões, as quais são reparadas por intensas reações de proliferação osteoblástica e possuem curso clínico semelhante ao das osteomielites crônicas inespecíficas, que podem evoluir para neoplasias. Objetivo: análise citogenética de amostra de periostite para detecção e descrição de alterações cromossômicas, principalmente as associadas com desenvolvimento de neoplasias. Métodos: material obtido de lesão em palato de paciente, um homem de 74 anos de idade, submetido anteriormente a cirurgias de remoção de carcinoma basocelular em nariz e cavidade oral. Após a coleta, com estudo histopatológico confirmando apenas material de periostite, a amostra foi submetida à análise citogenética a partir de cultura de células e bandamento GTG. Resultados: o cariótipo composto evidenciou, como alterações clonais, monossomia dos cromossomos 10, 15, 20 e 22; trissomia do cromossomo 22; inversão do cromossomo 12 e deleção de 15q. O grande número de alterações cromossômicas estaria relacionado com a alta taxa de proliferação celular, a qual poderia induzir replicação celular desbalanceada e instabilidade genética. Há genes, envolvidos com desenvolvimento de neoplasias, localizados nos pontos de quebra das alterações estruturais encontradas nos cromossomos 12 e 15. Conclusão: foram evidenciadas várias alterações cromossômicas que refletiriam a proliferação celular local. A análise citogenética em casos de periostite poderá auxiliar na descoberta de biomarcadores de prognóstico e ser utilizada, futuramente, na rotina médica para um melhor manejo dos pacientes.

Introduction: Periostitis is an inflammation of the soft tissues adjacent to the bone that affects the periosteum. There is little information in the literature about genetic alterations in these lesions, which are repaired by intense osteoblast proliferation reactions and present a clinical course that resembles that of nonspecific chronic osteomyelitis that may progress to neoplasms. Objective: Cytogenetic analysis of periostitis sample for detection and description of chromosomal alterations, especially those associated with cancer development. Methods: Material obtained from a palate lesion of a 74-year-old man who had previously undergone surgery to remove basal cell carcinoma in the nose and oral cavity. After collection, with a histopathological study confirming only periostitis material, the sample was submitted to a cytogenetic analysis from cell culture and GTG banding. Results: The composite karyotype showed, as clonal alterations, monosomy of chromosomes 10, 15, 20, and 22; trisomy of chromosome 22; inversion of chromosome 12, and deletion of 15q. The large number of chromosomal alterations would be related to the high rate of cell proliferation, which could induce unbalanced cell replication and genetic instability. There are genes, which are involved in the development of neoplasms, mapped at the breakpoints of structural changes found on chromosomes 12 and 15. Conclusion: Several chromosomal alterations that were observed would reflect local cell proliferation. Cytogenetic analysis of periostitis may help in the discovery of prognostic biomarkers and may be used in the medical routine for better patient management in the future.

COMPLICATIONS AND COST ANALYSIS OF HEMIPELVECTOMY FOR THE TREATMENT OF PELVIC TUMORS.

OBJECTIVE: Hemipelvectomy is a complex surgery with a high complication rate. Here, we aimed to identify factors related to the onset of complications and calculate their impacts on hospital costs. METHODS: We evaluated 31 consecutive patients who underwent hemipelvectomy between 1999 and 2015. We assessed the clinical and radiographic data to determine the patients' demographic factors, tumor and surgical characteristics, and complications. The individual hospital stays and financial balances were assessed up to 6 months following the index surgery. RESULTS: The overall complication rate was 61% (19/31). Infection was the most prevalent complication (36%). Immediate postoperative death occurred in 5/31 patients (16%); another 5 (16%) died after hospital discharge due to disease progression. Histological grade, previous surgery, and previous radiotherapy were not associated with complications or infection. Acetabular resections, bone reconstruction, and longer operative times were associated with infection, whereas older age, pelvic organ involvement, and comorbidities were associated with immediate postoperative death. Complications and infection were associated with 4.8- and 5.9-fold increases in hospital costs, respectively. CONCLUSIONS: Acetabular resection and bone reconstruction are important factors that increase short-term complication rates, infection rates, and hospital costs. Mortality was associated with older age and adjacent pelvic tumor progression. Level of Evidence: IV, case series.

OBJETIVO: Hemipelvectomia é uma cirurgia complexa associada a alta taxa de complicações. O objetivo foi identificar fatores relacionados a complicações e calcular o impacto sobre os custos hospitalares. MÉTODOS: Avaliamos 31 pacientes consecutivos submetidos à hemipelvectomia entre 1999 e 2015. Analisamos dados clínicos e radiográficos para determinar variáveis demográficas, características do tumor e cirurgia, e complicações. A internação hospitalar individual e o balanço financeiro foram calculados até seis meses após a cirurgia principal. RESULTADOS: A taxa de complicações foi de 61% (19/31). Infecção foi a complicação mais frequente (36%). Morte pós-operatória precoce foi observada em 5/31 pacientes (16%) e outros cinco (16%) morreram após alta hospitalar devido à progressão da doença. Grau histológico, cirurgia e radioterapias prévias não estiveram associadas com complicações ou infecções. Ressecções acetabulares, reconstruções ósseas e maiores tempos cirúrgicos estiveram associados com infecções, enquanto que mais idade, envolvimento de orgão pélvico e comorbidades estiveram associados com morte precoce. Complicações e infecções apresentaram aumento de 4,8-, e 5.9-vezes nos custos hospitalres. CONCLUSÕES: Ressecções acetabulares e reconstrução óssea são fatores importantes que aumentam as complicações, infecções e custos hospitalares. Mortalidade está associada com maior idade e progressão tumoral intrapélvica. Nível de Evidência IV, Série de casos.

Complications and cost analysis of hemipelvectomy for the treatment of pelvic tumors / Complicações e análise de custo da hemipelvectomia para o tratamento de tumores da pelve

ABSTRACT Objective: Hemipelvectomy is a complex surgery with a high complication rate. Here, we aimed to identify factors related to the onset of complications and calculate their impacts on hospital costs. Methods: We evaluated 31 consecutive patients who underwent hemipelvectomy between 1999 and 2015. We assessed the clinical and radiographic data to determine the patients' demographic factors, tumor and surgical characteristics, and complications. The individual hospital stays and financial balances were assessed up to 6 months following the index surgery. Results: The overall complication rate was 61% (19/31). Infection was the most prevalent complication (36%). Immediate postoperative death occurred in 5/31 patients (16%); another 5 (16%) died after hospital discharge due to disease progression. Histological grade, previous surgery, and previous radiotherapy were not associated with complications or infection. Acetabular resections, bone reconstruction, and longer operative times were associated with infection, whereas older age, pelvic organ involvement, and comorbidities were associated with immediate postoperative death. Complications and infection were associated with 4.8- and 5.9-fold increases in hospital costs, respectively. Conclusions: Acetabular resection and bone reconstruction are important factors that increase short-term complication rates, infection rates, and hospital costs. Mortality was associated with older age and adjacent pelvic tumor progression. Level of Evidence: IV, case series.

RESUMO Objetivo: Hemipelvectomia é uma cirurgia complexa associada a alta taxa de complicações. O objetivo foi identificar fatores relacionados a complicações e calcular o impacto sobre os custos hospitalares. Métodos: Avaliamos 31 pacientes consecutivos submetidos à hemipelvectomia entre 1999 e 2015. Analisamos dados clínicos e radiográficos para determinar variáveis demográficas, características do tumor e cirurgia, e complicações. A internação hospitalar individual e o balanço financeiro foram calculados até seis meses após a cirurgia principal. Resultados: A taxa de complicações foi de 61% (19/31). Infecção foi a complicação mais frequente (36%). Morte pós-operatória precoce foi observada em 5/31 pacientes (16%) e outros cinco (16%) morreram após alta hospitalar devido à progressão da doença. Grau histológico, cirurgia e radioterapias prévias não estiveram associadas com complicações ou infecções. Ressecções acetabulares, reconstruções ósseas e maiores tempos cirúrgicos estiveram associados com infecções, enquanto que mais idade, envolvimento de orgão pélvico e comorbidades estiveram associados com morte precoce. Complicações e infecções apresentaram aumento de 4,8-, e 5.9-vezes nos custos hospitalres. Conclusões: Ressecções acetabulares e reconstrução óssea são fatores importantes que aumentam as complicações, infecções e custos hospitalares. Mortalidade está associada com maior idade e progressão tumoral intrapélvica. Nível de Evidência IV, Série de casos.

MiR-708-5p is inversely associated with EWS/FLI1 Ewing sarcoma but does not represent a prognostic predictor.

BACKGROUND: Overall survival of Ewing sarcoma (EWS) remains poor and less than 30% of patients with metastatic or recurrent disease survive despite current treatments. Thus, there is a constant search for new biomarkers for diagnosis, prognosis and prediction of therapy. Numerous studies have reported the abnormal expression of miR-708-5p in tumors of different origins. However, its role in EWS remains unclear. PROCEDURE: qRT-PCR was performed in nineteen consecutive EWS samples and twelve non-tumor bone samples from age-matched controls. Functional assays were performed in SK-ES-1 cells transfected with miR-708 lentiviral-based vectors and results analyzed in terms of clonogenicity, migration, invasion and western blot. RESULTS: We show that miR-708-5p is downregulated in EWS tissues though no associations with any prognostic features such as HUVOS grade, event or survival were found in our cohort. Nonetheless, expression levels of this micro-RNA were inversely associated with the presence of the EWS/FLI1 translocation. When miR-708-5p was transfected into the SK-ES-1 cell line, it did not affect migration or clonogenicity, but promoted a significant increase on the invasive potential of cells endorsed with high expression of MMP2. CONCLUSIONS: Taken together, our results suggest that despite downregulated in EWS samples, this miRNA might represent a secondary genetic alteration derived from the pleiotropic cellular effects of the abnormal EWS/FLI1 transcription factor that does not affect tumor growth but instead, is related with the promotion of tumor invasion, not being suitable for future therapeutic intervention.

Prognostic value and functional role of ROCK2 in pediatric Ewing sarcoma.

Ewing's sarcoma (EWS) is a highly aggressive bone cancer that affects children and adolescents. Despite advances in multimodal management, 5-year event-free survival rates for patients presenting with metastases at diagnosis remain at 25%. As key regulators of actin organization, the Rho-associated coiled-coil containing protein kinases, ROCK1 and ROCK2, have been associated with cancer dissemination and poorer prognosis. Recently, in vitro data indicating ROCK2 as a molecular target for the treatment of EWS has been presented. Nonetheless, a deeper exploration of the contribution of this kinase dysregulation in EWS is still necessary. In this regard, the present study aimed to evaluate the expression of ROCK1 and ROCK2 in 23 pediatric tumor samples and to verify the prospect of using their pharmacological inhibition through functional assays. Our results showed positive immunostaining for ROCK1 and ROCK2 in the majority samples (75 and 65%, respectively). A significantly increased risk of incomplete remission in patients with positive immunostaining for ROCK2 was found (P=0.026), though no correlations with other prognostic features (huvos classification, FLI1/EWS status, relapse, metastasis or death) were observed. Associations with survival were merely suggestive. Apparent protein expression of both kinases was also found in EWS cell lines (SK-ES-1 and RD-ES). Treatments with selective ROCK inhibitors did not alter cell viability or migration in vitro. However, a significant increase in invasion was observed after treatment with SR3677 (ROCK2 inhibitor) and hydroxyfasudil (pan-inhibitor). Consequently, even though the majority of EWS samples included in our study showed positivity for ROCK1 and ROCK2, the lack of significant associations with prognosis and absence of appropriate responses to their inhibition in vitro does not support their prospective use as therapeutic targets for the treatment of this metastatic tumor. Larger cohort studies might provide more evidence on whether there is a specific role of ROCK kinases in EWS physiopathology.

Downregulation of miR-10B* is correlated with altered expression of mitotic kinases in osteosarcoma.

Dysregulated mitotic kinases have frequently been associated with cancer. Changes in their expression might result from diverse mechanisms including avoidance of the tight regulation exerted by miRNAs. Herein we show that miR-10b* is downregulated in osteosarcoma samples and demonstrate its correlation with PLK1, PLK4, BUB1, and BUBR1, which are strongly intercorrelated. The selection of miRNAs that coordinately target and regulate multiple members of cancer-related pathways are particularly advantageous to tumors. Thus, even though no associations with clinical parameters were found, our data place miR-10b* as a tumor suppressor that might contribute to guarantee genomic stability, deserving further functional confirmation.

Safety, osseointegration, and bone ingrowth analysis of PMMA-based porous cement on animal metaphyseal bone defect model.

Bone defects created after curettage of benign bone tumors are customarily filled with solid poly(methyl methacrylate) (PMMA) or other bone substitutes. In this study, we depicted a porous PMMA-based cement (produced by mixing sodium bicarbonate and citric acid) and evaluated the prospect of its clinic application. Cement samples were characterized by high-performance liquid chromatography (HPLC) coupled to mass spectrometry and its cytotoxicity evaluated in fibroblast cultures. Implantation in rabbits allowed the histologic analysis of bone, kidneys, and liver for toxicity and coagulation tests, and MRI images for hemostasis evaluation. Osseointegration was analyzed through radiography, microtomography (micro-CT), SEM, and histology of sheep specimens. Rabbit specimens were analyzed 1, 4, and 7 days after implantation of porous or solid bone cement in 6.0 mm femoral defects. Sheep specimens were analyzed 3 and 6 months after implantation or not of porous or solid cement in 15.0 mm subchondral tibial defects. The production process did not release any detectable toxic substance but slightly reduced fibroblast proliferation in vitro. Until 7 days after surgery, no local or systemic alterations could be detected in histology, or hematoma formation in histology or MRI. Sheep implants showed 6 mm linear ingrowth from the bone-cement interface and 20% bone ingrowth considering the whole defect area. Radiography, micro-CT, SEM, and histology confirmed these findings. We conclude that our porous PMMA-based cement is an attractive alternative treatment for bone defect filling that combines osseointegration and early weight bearing. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 649-658, 2018.

Osteointegration of porous absorbable bone substitutes: A systematic review of the literature.

Biomaterials' structural characteristics and the addition of osteoinductors influence the osteointegration capacity of bone substitutes. This study aims to identify the characteristics of porous and resorbable bone substitutes that influence new bone formation. An Internet search for studies reporting new bone formation rates in bone defects filled with porous and resorbable substitutes was performed in duplicate using the PubMed, Web of Science, Scielo, and University of São Paulo Digital Library databases. Metaphyseal or calvarial bone defects 4 to 10 mm in diameter from various animal models were selected. New bone formation rates were collected from the histomorphometry or micro-CT data. The following variables were analyzed: animal model, bone region, defect diameter, follow-up time after implantation, basic substitute material, osteoinductor addition, pore size and porosity. Of 3,266 initially identified articles, 15 articles describing 32 experimental groups met the inclusion criteria. There were no differences between the groups in the experimental model characteristics, except for the follow-up time, which showed a very weak to moderate correlation with the rate of new bone formation. In terms of the biomaterial and structural characteristics, only porosity showed a significant influence on the rate of new bone formation. Higher porosity is related to higher new bone formation rates. The influence of other characteristics could not be identified, possibly due to the large variety of experimental models and methodologies used to estimate new bone formation rates. We suggest the inclusion of standard control groups in future experimental studies to compare biomaterials.

Diagnostic performance of magnetic resonance imaging in the assessment of periosteal reactions in bone sarcomas using conventional radiography as the reference.

OBJECTIVE: To evaluate the performance of magnetic resonance imaging (MRI) in detecting periosteal reactions and to compare MRI and conventional radiography (CR) in terms of the classification of periosteal reactions. MATERIALS AND METHODS: Retrospective study of 42 consecutive patients (mean age, 22 years; 20 men) with a confirmed diagnosis of osteosarcoma or Ewing's sarcoma, MRI and CR images having been acquired pretreatment. Three blinded radiologists detected periosteal reactions and evaluated each periosteal reaction subtype in CR and MRI images: Codman's triangle; laminated; and spiculated. The CR was used as a benchmark to calculate the diagnostic performance. We used the kappa coefficient to assess interobserver reproducibility. A two-tailed Fisher's exact test was used in order to assess contingency between CR and MRI classifications. RESULTS: In the detection of periosteal reactions, MRI showed high specificity, a high negative predictive value, and low-to-moderate sensitivity. For CR and for MRI, the interobserver agreement for periosteal reaction was almost perfect, whereas, for the classification of different subtypes of periosteal reaction, it was higher for the Codman's triangle subtype and lower for the spiculated subtype. There was no significant difference between MRI and CR in terms of the classifications (p < 0.05). CONCLUSION: We found no difference between MRI and CR in terms of their ability to classify periosteal reactions. MRI showed high specificity and almost perfect interobserver agreement for the detection of periosteal reactions. The interobserver agreement was variable for the different subtypes of periosteal reaction.

OBJETIVO: Avaliar o desempenho da ressonância magnética (RM) na detecção de reação periosteal e comparar a classificação de presença ou ausência de reações periosteais entre a RM e a radiografia convencional (RC). MATERIAIS E MÉTODOS: Estudo retrospectivo incluindo 42 pacientes consecutivos (idade média, 22 anos; 20 homens) com diagnóstico confirmado de osteossarcoma ou sarcoma de Ewing, tendo exames de RM e RC adquiridos pré-tratamento. Três radiologistas avaliaram às cegas a presença ou ausência de reação periosteal e de cada subtipo de reação periosteal nas imagens de RC e RM: triângulo de Codman, multilamelada e espiculada. A RC foi usada como padrão de referência para cálculo do desempenho diagnóstico. Foi utilizado o coeficiente kappa para reprodutibilidade interobservador. Adicionalmente, foi realizado teste exato de Fisher bicaudal para avaliar se houve diferença significativa entre as leituras da RC e RM. RESULTADOS: A RM mostrou alta especificidade, alto valor preditivo negativo e baixa sensibilidade na detecção de reação periosteal. A concordância interobservador para a reação periosteal foi quase perfeita para a RC e RM. A concordância interobservador para a classificação dos diferentes subtipos de reação periosteal foi maior para o subtipo triângulo de Codman e menor para o subtipo espiculada. Não houve diferença na detecção por RM e RC (p < 0,05). CONCLUSÃO: Não houve diferença significativa entre as classificações da presença ou ausência de reações periosteais entre os métodos RC e RM. A RM apresentou alta especificidade e concordância interobservador quase perfeita para a detecção de reação periosteal. A concordância interobservador para os diferentes subtipos de reação periosteal foi variável.

Osteointegration of porous absorbable bone substitutes: A systematic review of the literature

Biomaterials' structural characteristics and the addition of osteoinductors influence the osteointegration capacity of bone substitutes. This study aims to identify the characteristics of porous and resorbable bone substitutes that influence new bone formation. An Internet search for studies reporting new bone formation rates in bone defects filled with porous and resorbable substitutes was performed in duplicate using the PubMed, Web of Science, Scielo, and University of São Paulo Digital Library databases. Metaphyseal or calvarial bone defects 4 to 10 mm in diameter from various animal models were selected. New bone formation rates were collected from the histomorphometry or micro-CT data. The following variables were analyzed: animal model, bone region, defect diameter, follow-up time after implantation, basic substitute material, osteoinductor addition, pore size and porosity. Of 3,266 initially identified articles, 15 articles describing 32 experimental groups met the inclusion criteria. There were no differences between the groups in the experimental model characteristics, except for the follow-up time, which showed a very weak to moderate correlation with the rate of new bone formation. In terms of the biomaterial and structural characteristics, only porosity showed a significant influence on the rate of new bone formation. Higher porosity is related to higher new bone formation rates. The influence of other characteristics could not be identified, possibly due to the large variety of experimental models and methodologies used to estimate new bone formation rates. We suggest the inclusion of standard control groups in future experimental studies to compare biomaterials.

Diagnostic performance of magnetic resonance imaging in the assessment of periosteal reactions in bone sarcomas using conventional radiography as the reference / Desempenho diagnóstico da ressonância magnética na avaliação de reações periosteais em sarcomas ósseos utilizando a radiografia convencional como padrão de referência

Abstract Objective: To evaluate the performance of magnetic resonance imaging (MRI) in detecting periosteal reactions and to compare MRI and conventional radiography (CR) in terms of the classification of periosteal reactions. Materials and Methods: Retrospective study of 42 consecutive patients (mean age, 22 years; 20 men) with a confirmed diagnosis of osteosarcoma or Ewing's sarcoma, MRI and CR images having been acquired pretreatment. Three blinded radiologists detected periosteal reactions and evaluated each periosteal reaction subtype in CR and MRI images: Codman's triangle; laminated; and spiculated. The CR was used as a benchmark to calculate the diagnostic performance. We used the kappa coefficient to assess interobserver reproducibility. A two-tailed Fisher's exact test was used in order to assess contingency between CR and MRI classifications. Results: In the detection of periosteal reactions, MRI showed high specificity, a high negative predictive value, and low-to-moderate sensitivity. For CR and for MRI, the interobserver agreement for periosteal reaction was almost perfect, whereas, for the classification of different subtypes of periosteal reaction, it was higher for the Codman's triangle subtype and lower for the spiculated subtype. There was no significant difference between MRI and CR in terms of the classifications (p < 0.05). Conclusion: We found no difference between MRI and CR in terms of their ability to classify periosteal reactions. MRI showed high specificity and almost perfect interobserver agreement for the detection of periosteal reactions. The interobserver agreement was variable for the different subtypes of periosteal reaction.

Resumo Objetivo: Avaliar o desempenho da ressonância magnética (RM) na detecção de reação periosteal e comparar a classificação de presença ou ausência de reações periosteais entre a RM e a radiografia convencional (RC). Materiais e Métodos: Estudo retrospectivo incluindo 42 pacientes consecutivos (idade média, 22 anos; 20 homens) com diagnóstico confirmado de osteossarcoma ou sarcoma de Ewing, tendo exames de RM e RC adquiridos pré-tratamento. Três radiologistas avaliaram às cegas a presença ou ausência de reação periosteal e de cada subtipo de reação periosteal nas imagens de RC e RM: triângulo de Codman, multilamelada e espiculada. A RC foi usada como padrão de referência para cálculo do desempenho diagnóstico. Foi utilizado o coeficiente kappa para reprodutibilidade interobservador. Adicionalmente, foi realizado teste exato de Fisher bicaudal para avaliar se houve diferença significativa entre as leituras da RC e RM. Resultados: A RM mostrou alta especificidade, alto valor preditivo negativo e baixa sensibilidade na detecção de reação periosteal. A concordância interobservador para a reação periosteal foi quase perfeita para a RC e RM. A concordância interobservador para a classificação dos diferentes subtipos de reação periosteal foi maior para o subtipo triângulo de Codman e menor para o subtipo espiculada. Não houve diferença na detecção por RM e RC (p < 0,05). Conclusão: Não houve diferença significativa entre as classificações da presença ou ausência de reações periosteais entre os métodos RC e RM. A RM apresentou alta especificidade e concordância interobservador quase perfeita para a detecção de reação periosteal. A concordância interobservador para os diferentes subtipos de reação periosteal foi variável.