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STUDY DESIGN: Retrospective study. PURPOSE: To compare and correlate technetium-99m methylene diphosphonate uptake between benign and metastatic bone lesions using semiquantitative analysis of maximum standard uptake value (SUVmax) and mean Hounsfield unit (HU) in single-photon emission computed tomography-computed tomography (SPECT-CT). OVERVIEW OF LITERATURE: Qualitative interpretation of metastatic bone lesions in breast cancer on bone scintigraphy is often complicated by coexisting benign lesions. METHODS: In total, 185 lesions were identified on bone and SPECT-CT scans from 32 patients. Lesions were classified as metastatic (109 sclerotic lesions) and benign (76 lesions) morphologically on low-dose CT. Semiquantitative analysis using SUVmax and mean HU was performed on the lesions and compared. To discriminate benign and metastatic lesions, the correlation between SUVmax and mean HU was determined using the intraclass correlation coefficients. RESULTS: The SUVmax was higher in metastatic lesions (20.66±14.36) but lower in benign lesions (10.18±12.79) (p<0.001). The mean HU was lower in metastatic lesions (166.62±202.02) but higher in benign lesions (517.65±192.8) (p<0.001). A weak negative correlation was found between the SUVmax and the mean HU for benign lesions, and a weak positive correlation was noted between the SUVmax and the mean HU on malignant lesions with no statistical significance (p=0.394 and 0.312, respectively). The cutoff values obtained were 10.8 for SUVmax (82.6% sensitivity and 84.2% specificity) and 240.86 for the mean HU (98.7% sensitivity and 88.1% specificity) in differentiating benign from malignant bone lesions. CONCLUSIONS: Semiquantitative assessment using SUVmax and HU can complement qualitative analysis. Metastatic lesions had higher SUVmax but lower mean HU than benign lesions, whereas benign lesions demonstrated higher mean HU but lower SUVmax. A weak correlation was found between the SUVmax and the mean HU on malignant and benign lesions. Cutoff values of 10.8 for the SUVmax and 240.86 for the mean HU may differentiate bone metastases from benign lesions.

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Air pollution is a serious challenge to humankind as it poses many health threats. It can be measured using the air quality index (AQI). Air pollution is the result of contamination of both outdoor and indoor environments. The AQI is being monitored by various institutions globally. The measured air quality data are kept mostly for public use. Using the previously calculated AQI values, the future values of AQI can be predicted, or the class/category value of the numeric value can be obtained. This forecast can be performed with more accuracy using supervised machine learning methods. In this study, multiple machine-learning approaches were used to classify PM2.5 values. The values for the pollutant PM2.5 were classified into different groups using machine learning algorithms such as logistic regression, support vector machines, random forest, extreme gradient boosting, and their grid search equivalents, along with the deep learning method multilayer perceptron. After performing multiclass classification using these algorithms, the parameters accuracy and per-class accuracy were used to compare the methods. As the dataset used was imbalanced, a SMOTE-based approach for balancing the dataset was used. Compared to all other classifiers that use the original dataset, the accuracy of the random forest multiclass classifier with SMOTE-based dataset balancing was found to provide better accuracy.

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BACKGROUND: Laparoscopic sleeve gastrectomy (LSG) is the most commonly performed metabolic surgery worldwide. There are few mid- to long-term studies for LSG, especially from the Indian subcontinent. OBJECTIVE: The primary outcome of the study was percent total weight loss (%TWL), and secondary outcomes included type 2 diabetes mellitus remission (T2DM) rates, comorbidity resolution rates, revisional surgeries, and complications related to LSG, 3 and 5 years after surgery. METHOD: The study was a single-center, retrospective analysis from patients who underwent primary as well as revisional LSG between January 2012 and December 2013 from a tertiary care center in India. We included patients who completed a minimum follow-up of 5 years. Details of the patients were collected from outpatient and inpatient case sheet records, during their follow-up. RESULTS: Out of a total of 284 patients, 57% were females. Mean baseline body mass index (BMI) was 44.9 ± 7.9 kg/m2. The diabetic population comprised 14.8% of the total patients. Mean %TWL at 5 years was 26.0 ± 9.9%. T2DM remission at 1, 3, and 5 years were 78.5%, 71.4%, and 66.6%, respectively. Preoperative BMI (p = 0.02), glycosylated hemoglobin (HbA1c) (p = 0.04), duration of diabetes in years (p = 0.04), and preoperative insulin usage (p = 0.04) were the preoperative predictors for T2DM remission. Early (< 30 days) and late (> 30 days) complications were seen in 4.5% and 0.7% of the population, respectively. CONCLUSION: Weight loss after LSG was maintained in the majority of the patients, while a small proportion has significant weight regain at 5 years. T2DM resolution and other comorbidity resolutions were well supported after LSG.

Asunto(s)

Diabetes Mellitus Tipo 2/terapia , Gastrectomía , Laparoscopía , Adulto , Índice de Masa Corporal , Comorbilidad , Femenino , Estudios de Seguimiento , Hemoglobina Glucada/análisis , Humanos , India , Masculino , Persona de Mediana Edad , Obesidad Mórbida/cirugía , Inducción de Remisión , Estudios Retrospectivos , Pérdida de Peso

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Commissioning of the CANREB (CANadian Rare isotope facility with Electron Beam ion source) system and its associated beamlines has recently begun at TRIUMF. At the head of this beamline is an ion source used to produce stable alkaline ions with energy up to 60 keV for the CANREB system. Throughout commissioning, it is essential to have a means of verifying beam quality and ensuring that the required beam parameters along the beamline are met. This is accomplished using tomography reconstruction, which consists of taking one-dimensional scans at different projections and reconstructing an image of the beam in two dimensions using the maximum entropy algorithm. Tomography enables the visualization of the shape of the beam as well as the investigation into the possible presence of aberrations. Initially, tomography reconstruction is performed by using simulated beam profiles at the measurement locations and is then performed by using measured beam profiles. Additionally, these measurements are benchmarked by fitting the initial beam parameters in our beam optics model, and the results are presented.

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BACKGROUND: The literature on osteosarcoma survival generally focuses on tumor and treatment variables, although it is unclear whether and how ethnic and socioeconomic factors might influence survival. QUESTIONS/PURPOSES: We therefore investigated the relative contribution of socioeconomic influences together with more traditional tumor-specific factors on osteosarcoma survival. METHODS: We performed survival analyses on two national databases in two countries. Using multivariable analyses, we compared these with corresponding institution-specific survival to determine if socioeconomic factors might impact osteosarcoma survival. RESULTS: East Asian descent, state-specific treatment, female sex, treatment in the 1990s, low-grade disease, intracompartmental disease, small size, wide resections as opposed to forequarter or hindquarter amputations, and single primaries were good prognostic factors. Survival was better in the more affluent states. Males were affected at an older age than females. Blacks tended to have larger tumors, although their overall survival was similar to whites. East Asians were more likely to be treated in the 1990s with wide resections for smaller tumors and were located around states associated with good treatment. East Asians in Singapore and the United States had the same survival. Survival in East Asians in Singapore was similar to that of other races. The provision of health care for osteosarcoma varies greatly across the United States but is uniform in the socialized medical system in Singapore. Hence, the observed differences in the United States were likely the result of socioeconomic factors. CONCLUSIONS: Our analysis suggests ethnic and economic bias may influence survival in osteosarcoma and should receive greater attention in the collective literature on survival analyses. LEVEL OF EVIDENCE: Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

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Neoplasias Óseas/mortalidad , Osteosarcoma/mortalidad , Factores Socioeconómicos , Adolescente , Adulto , Factores de Edad , Amputación Quirúrgica/mortalidad , Neoplasias Óseas/economía , Neoplasias Óseas/etnología , Neoplasias Óseas/patología , Neoplasias Óseas/cirugía , Distribución de Chi-Cuadrado , Niño , Preescolar , Estudios Transversales , Femenino , Humanos , Renta , Lactante , Estimación de Kaplan-Meier , Masculino , Análisis Multivariante , Osteosarcoma/economía , Osteosarcoma/etnología , Osteosarcoma/patología , Osteosarcoma/cirugía , Osteotomía/mortalidad , Modelos de Riesgos Proporcionales , Grupos Raciales , Estudios Retrospectivos , Programa de VERF , Factores Sexuales , Singapur , Tasa de Supervivencia , Factores de Tiempo , Resultado del Tratamiento , Estados Unidos/epidemiología , Adulto Joven

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INTRODUCTION: Osteosarcoma treatment has experienced a renaissance in the last 3 decades with the institution of multimodality treatment involving multiagent chemotherapy and surgery. Yet globally, treatment success has stagnated at about 70% survival at 5 years in most single institution series. We performed survival analyses on 2 national databases in 2 countries and compared these with corresponding institution specific survival. MATERIALS AND METHODS: All patients with the diagnostic code of non-metastatic intramedullary osteosarcoma in the long bones of the upper and lower limbs less than 30 years of age were selected from the Surveillance Epidemiology and End Result (SEER) database to ensure uniformity with respect to disease and treatment. We studied the factors: ethnicity, gender, age, grade, histology, size, site, surgery, compartmentalisation, number of primaries and venue of treatment for their contribution to survival. In addition, the data were stratified into 3 decades (seventies, eighties and nineties) to account for variations due to the evolution of treatment paradigms and imaging modalities. RESULTS: Institution-specific survival was predictably better than national survival in the 4 databases. One thousand patients were selected from the SEER database. Oriental descent, state-specific treatment, female gender, treatment in the nineties, low-grade disease, intra-compartmental disease, small size, wide resections as opposed to forequarter or hindquarter amputations, and single primaries were good prognostic factors on univariate analysis as well as multivariate analysis (P <0.05). Survival was better in the more affluent states (P <0.05). Males were affected at an older age than females (P = 0.004). Blacks tended to have larger tumours although their overall survival was similar to whites. Orientals were more likely to be treated in the nineties with wide resections for smaller tumours and were located around states associated with good treatment. Orientals in Singapore and the United States had the same survival (P = 0.45). Survival in Orientals in Singapore was not significantly different from other races. The standard of healthcare for osteosarcoma varies greatly across the United States but is uniform in Singapore. Hence the observed differences in the United States were likely due to socioeconomic factors. CONCLUSION: This analysis confirms the importance of a number of prognostic variables in osteosarcoma and suggests the possibility of an ethnic and economic bias for good survival.

Asunto(s)

Neoplasias Óseas/mortalidad , Osteosarcoma/mortalidad , Adolescente , Adulto , Pueblo Asiatico , Población Negra , Neoplasias Óseas/epidemiología , Neoplasias Óseas/etnología , Niño , Preescolar , Bases de Datos Factuales , Femenino , Humanos , Lactante , Recién Nacido , Internacionalidad , Estimación de Kaplan-Meier , Masculino , Osteosarcoma/epidemiología , Osteosarcoma/etnología , Pronóstico , Sistema de Registros , Singapur/epidemiología , Población Blanca , Adulto Joven

RESUMEN

INTRODUCTION: Cryosurgery for tumoural ablation traditionally involves instilling liquid nitrogen into a tumoural bed. The inability to control precise delivery can result in potentially disastrous consequences of skin necrosis and nitrogen gas embolism. In this study, we evaluated a probe-based closed cryosurgical system, which eliminates these risks. MATERIALS AND METHODS: We performed a prospective evaluation of 36 cases of bone tumours treated with a probe-based cryosurgical system at the National University Hospital, Singapore. Cases consisted of patients with benign aggressive tumours (42%), primary malignant bone tumours (25%) and bone metastases (33%). In primary bone tumours, the aim of therapy was cure. In bone metastasis, the aim of therapy was palliation defined as the relief of symptoms for the patients' remaining lifetime. RESULTS: In the primary bone tumour group, no recurrences were reported. In the metastases group, where the intention was palliation, there were 3 cases of radiological relapses (P = 0.02) and 2 clinical relapses. Kaplan-Meier evaluation showed a statistically significant tendency for radiological relapse in metastatic disease versus primary disease (P = 0.02). Median time for relapse free survival in the metastatic group was 17 months (P = 0.01). There were 4 deaths in the metastatic group due to progression of disease unrelated to the index region of cryosurgical treatment. There were no deaths in the primary bone tumor group. We had 2 complications from this therapy involving fractures through the cryoablated segments. One case healed spontaneously and the other was most expediently managed with a shoulder hemiarthoplasty. There were no skin burns or embolic complications. CONCLUSION: Good clinical efficacy with probe delivered cryotherapy has been shown in this group of 32 patients with cure in all primary disease. Relapse occurred in only a small proportion of patients with bone metastasis.

Asunto(s)

Argón , Neoplasias Óseas/cirugía , Criocirugía/métodos , Adolescente , Adulto , Anciano , Neoplasias Óseas/mortalidad , Femenino , Humanos , Estimación de Kaplan-Meier , Masculino , Persona de Mediana Edad , Cuidados Paliativos/métodos , Estudios Prospectivos , Singapur , Estadística como Asunto , Adulto Joven

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A detailed experimental and simulation study of the extraction of a 24 keV He(+) beam from an ECR ion source and the subsequent beam transport through an analyzing magnet is presented. We find that such a slow ion beam is very sensitive to space-charge forces, but also that the neutralization of the beam's space charge by secondary electrons is virtually complete for beam currents up to at least 0.5 mA. The beam emittance directly behind the extraction system is 65 π mm mrad and is determined by the fact that the ion beam is extracted in the strong magnetic fringe field of the ion source. The relatively large emittance of the beam and its non-paraxiality lead, in combination with a relatively small magnet gap, to significant beam losses and a five-fold increase of the effective beam emittance during its transport through the analyzing magnet. The calculated beam profile and phase-space distributions in the image plane of the analyzing magnet agree well with measurements. The kinematic and magnet aberrations have been studied using the calculated second-order transfer map of the analyzing magnet, with which we can reproduce the phase-space distributions of the ion beam behind the analyzing magnet. Using the transfer map and trajectory calculations we have worked out an aberration compensation scheme based on the addition of compensating hexapole components to the main dipole field by modifying the shape of the poles. The simulations predict that by compensating the kinematic and geometric aberrations in this way and enlarging the pole gap the overall beam transport efficiency can be increased from 16% to 45%.

RESUMEN

We previously showed that interstitial fluid pressure (IFP) may be an alternate regulator of angiogenesis in solid tumors. Given the accepted link between hypoxia-induced factor and angiogenesis this study investigated the effect of IFP on hypoxia-inducible factor (HIF-1α) and vascular endothelial growth factor (VEGF) in human osteosarcoma xenografts in SCID mice and in different hypoxic environments. Tumors were grown either at heterotopic (flank) or orthotopic (medullary canal of the proximal tibia) sites in the host animal. Microfluidic probes determined pH, O(2)-saturation, IFP, and peripheral blood flow perfusion continuously. We assessed tumor growth in the orthotopic site (n = 15) by softex radiographs weekly, 3D microCT, histological evaluation, and for molecular responses. An increased cytoplasmic immunohistostaining of cells for HIF-1α (p = 0.03) and VEGF-A (p = 0.004) on the outer periphery was noted compared to the tumor center, with VEGFR2 uniformly stained throughout. This paralleled a raised state of interstitial hypertension (p = 0.007) in the tumor center relative to the peripheral surface but was inconsistent with a state of hypoxia (p = 0.03) in the tumor center. In vitro culture of human osteosarcoma cell lines (HOS, U2OS) and a human osteoblast control at 0- and 20-mmHg of hydrostatic pressure revealed suppression of HIF-1α (p = 0.02) and VEGF-A (p = 0.02) gene expression when IFP was raised, while the effect on VEGFR1 was equivocal. This study proposes an alternative regulatory angiogenic pathway via the influence of IFP on cancer cell function. The identification of a mechanistic cellular link to the physical parameter becomes an important tool to evaluate cancer cell growth within solid tumors.

Asunto(s)

Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Neovascularización Patológica , Osteosarcoma/metabolismo , Animales , Hipoxia de la Célula , Línea Celular Tumoral , Líquido Extracelular/metabolismo , Regulación de la Expresión Génica , Humanos , Hipoxia , Ratones , Trasplante de Neoplasias , Osteoblastos/metabolismo , Presión , Transducción de Señal , Factor A de Crecimiento Endotelial Vascular/metabolismo , Receptor 1 de Factores de Crecimiento Endotelial Vascular/biosíntesis

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<p><b>INTRODUCTION</b>Osteosarcoma treatment has experienced a renaissance in the last 3 decades with the institution of multimodality treatment involving multiagent chemotherapy and surgery. Yet globally, treatment success has stagnated at about 70% survival at 5 years in most single institution series. We performed survival analyses on 2 national databases in 2 countries and compared these with corresponding institution specific survival.</p><p><b>MATERIALS AND METHODS</b>All patients with the diagnostic code of non-metastatic intramedullary osteosarcoma in the long bones of the upper and lower limbs less than 30 years of age were selected from the Surveillance Epidemiology and End Result (SEER) database to ensure uniformity with respect to disease and treatment. We studied the factors: ethnicity, gender, age, grade, histology, size, site, surgery, compartmentalisation, number of primaries and venue of treatment for their contribution to survival. In addition, the data were stratified into 3 decades (seventies, eighties and nineties) to account for variations due to the evolution of treatment paradigms and imaging modalities.</p><p><b>RESULTS</b>Institution-specific survival was predictably better than national survival in the 4 databases. One thousand patients were selected from the SEER database. Oriental descent, state-specific treatment, female gender, treatment in the nineties, low-grade disease, intra-compartmental disease, small size, wide resections as opposed to forequarter or hindquarter amputations, and single primaries were good prognostic factors on univariate analysis as well as multivariate analysis (P <0.05). Survival was better in the more affluent states (P <0.05). Males were affected at an older age than females (P = 0.004). Blacks tended to have larger tumours although their overall survival was similar to whites. Orientals were more likely to be treated in the nineties with wide resections for smaller tumours and were located around states associated with good treatment. Orientals in Singapore and the United States had the same survival (P = 0.45). Survival in Orientals in Singapore was not significantly different from other races. The standard of healthcare for osteosarcoma varies greatly across the United States but is uniform in Singapore. Hence the observed differences in the United States were likely due to socioeconomic factors.</p><p><b>CONCLUSION</b>This analysis confirms the importance of a number of prognostic variables in osteosarcoma and suggests the possibility of an ethnic and economic bias for good survival.</p>

Asunto(s)

Adolescente , Adulto , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Adulto Joven , Población Negra , Pueblo Asiatico , Neoplasias Óseas , Epidemiología , Etnología , Mortalidad , Bases de Datos Factuales , Población Blanca , Internacionalidad , Estimación de Kaplan-Meier , Osteosarcoma , Epidemiología , Etnología , Mortalidad , Pronóstico , Sistema de Registros , Singapur , Epidemiología

RESUMEN

<p><b>INTRODUCTION</b>Cryosurgery for tumoural ablation traditionally involves instilling liquid nitrogen into a tumoural bed. The inability to control precise delivery can result in potentially disastrous consequences of skin necrosis and nitrogen gas embolism. In this study, we evaluated a probe-based closed cryosurgical system, which eliminates these risks.</p><p><b>MATERIALS AND METHODS</b>We performed a prospective evaluation of 36 cases of bone tumours treated with a probe-based cryosurgical system at the National University Hospital, Singapore. Cases consisted of patients with benign aggressive tumours (42%), primary malignant bone tumours (25%) and bone metastases (33%). In primary bone tumours, the aim of therapy was cure. In bone metastasis, the aim of therapy was palliation defined as the relief of symptoms for the patients' remaining lifetime.</p><p><b>RESULTS</b>In the primary bone tumour group, no recurrences were reported. In the metastases group, where the intention was palliation, there were 3 cases of radiological relapses (P = 0.02) and 2 clinical relapses. Kaplan-Meier evaluation showed a statistically significant tendency for radiological relapse in metastatic disease versus primary disease (P = 0.02). Median time for relapse free survival in the metastatic group was 17 months (P = 0.01). There were 4 deaths in the metastatic group due to progression of disease unrelated to the index region of cryosurgical treatment. There were no deaths in the primary bone tumor group. We had 2 complications from this therapy involving fractures through the cryoablated segments. One case healed spontaneously and the other was most expediently managed with a shoulder hemiarthoplasty. There were no skin burns or embolic complications.</p><p><b>CONCLUSION</b>Good clinical efficacy with probe delivered cryotherapy has been shown in this group of 32 patients with cure in all primary disease. Relapse occurred in only a small proportion of patients with bone metastasis.</p>

Asunto(s)

Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto Joven , Argón , Neoplasias Óseas , Mortalidad , Cirugía General , Criocirugía , Métodos , Estimación de Kaplan-Meier , Cuidados Paliativos , Métodos , Estudios Prospectivos , Singapur , Estadística como Asunto

RESUMEN

We have started an experimental and theoretical program to better understand the extraction and transport of intense multiply charged ion beams from an electron cyclotron resonance ion source (ECRIS). In this paper we present the first results of this program concerning a simple, monocomponent He(+) beam extracted from an ECRIS. We have calculated the ion trajectories starting from the ECRIS plasma electrode up to the image plane of the analyzing magnet taking into account space-charge effects and fringe fields. The initial phase-space distribution of the He(+) beam at the extraction aperture has been calculated with a particle-in-cell code. To check the simulations we have measured beam profiles with a viewing screen both before and after the analyzing magnet. In addition also measurements with a pepperpot emittance meter located behind the analyzing magnet have been performed. We find good agreement between these measurements and simulations showing that (i) there is a significant compensation of the space charge and that (ii) our analyzing magnet causes a severe increase in effective beam emittance.

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Lacerated skeletal muscles often do not recover full function after repair. Denervated muscles with altered myosin heavy chain isoform (MHC) profiles are known to result in functional impairment. We studied the functional recovery of lacerated muscles, assessing MHC profile changes in association to the involvement of the intramuscular nerve (IM). We tested three lacerated models using the rabbit's medial gastrocnemius where the IM was either cut (NNR), repaired (NR), or preserved intact (NP). Muscles were assessed 7 months after repair for muscle atrophy, isometric contraction (by electrical stimulation), and fibrosis formation at the lesion site. Changes in myofibrillar actomyosin adenosine triphosphatase activity, MHC profile, regenerating myofibers and reinnervation were assessed by Western blot, histology, or immunohistology. Lacerated muscles with a repaired (NR) or an intact (NP) IM showed good recovery, with no significant changes in the MHC profile. Muscles where the IM was not repaired (NNR) resulted in significant scar area at the lesion site (p < 0.05), muscle atrophy (67%, p < 0.05) and loss in contractile properties (63% of the uninjured side, p < 0.05). At 7 months, all muscles were reinnervated. However, the NNR had an inappropriate (polyneural) and poorly distributed reinnervation, the presence of regenerating myofibers, and demonstrated a fast-to-slow MHC transition (71%:29% to 44%:56%, ANOVA, p = 0.018). This was associated to the cut IM when the NNR muscle was lacerated. Poor reinnervation in lacerated skeletal muscles alters the myosin heavy chain profile permanently. This study provides a rationale to also consider biological solutions to improve nerve regeneration and reinnervation in the surgical repair of lacerated muscles.

Asunto(s)

Músculo Esquelético/lesiones , Músculo Esquelético/inervación , Cadenas Pesadas de Miosina/análisis , Acetilcolinesterasa/análisis , Adenosina Trifosfatasas/metabolismo , Animales , Placa Motora/enzimología , Músculo Esquelético/química , Regeneración Nerviosa , Isoformas de Proteínas , Conejos

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Osteosarcomas are the most prevalent primary bone tumors found in pediatric patients. To understand their molecular etiology, cell culture models are used to define disease mechanisms under controlled conditions. Many osteosarcoma cell lines (e.g., SAOS-2, U2OS, MG63) are derived from Caucasian patients. However, patients exhibit individual and ethnic differences in their responsiveness to irradiation and chemotherapy. This motivated the establishment of osteosarcoma cell lines (OS1, OS2, OS3) from three ethnically Chinese patients. OS1 cells, derived from a pre-chemotherapeutic tumor in the femur of a 6-year-old female, were examined for molecular markers characteristic for osteoblasts, stem cells, and cell cycle control by immunohistochemistry, reverse transcriptase-PCR, Western blotting and flow cytometry. OS1 have aberrant G-banded karyotypes, possibly reflecting chromosomal abnormalities related to p53 deficiency. OS1 had ossification profiles similar to human fetal osteoblasts rather than SAOS-2 which ossifies ab initio (P < 0.05). Absence of p53 correlates with increased Runx2 expression, while the slow proliferation of OS1 cells is perhaps attenuated by pRB retention. OS1 express mesenchymal stem cell markers (CD44, CD105) and differ in relative expression of CD29, CD63, and CD71 to SAOS-2. (P < 0.05). Cell cycle synchronization with nocodazole did not affect Runx2 and CDK1 levels but decreased cyclin-E and increased cyclin-A (P < 0.05). Xenotransplantion of OS1 in SCID mice yields spontaneous tumors that were larger and grew faster than SAOS-2 transplants. Hence, OS1 is a new osteosarcoma cell culture model derived from a pre-chemotherapeutic ethnic Chinese patient, for mechanistic studies and development of therapeutic strategies to counteract metastasis and deregulation of mesenchymal development.

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Diferenciación Celular , Subunidad alfa 1 del Factor de Unión al Sitio Principal/metabolismo , Osteoblastos/patología , Osteosarcoma/metabolismo , Osteosarcoma/patología , Proteína de Retinoblastoma/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Adolescente , Animales , Antígenos CD/metabolismo , Pueblo Asiatico , Calcificación Fisiológica/fisiología , Ciclo Celular/efectos de los fármacos , Desdiferenciación Celular , Línea Celular Tumoral , Proliferación Celular , Niño , Aberraciones Cromosómicas , Colágeno Tipo I/metabolismo , Subunidad alfa 1 del Factor de Unión al Sitio Principal/genética , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/metabolismo , Ciclinas/genética , Ciclinas/metabolismo , Femenino , Expresión Génica/genética , Humanos , Antígeno Ki-67/metabolismo , Ratones , Ratones SCID , Nocodazol/farmacología , Osteocalcina/metabolismo , Osteosarcoma/diagnóstico , Osteosarcoma/genética , Proteína de Retinoblastoma/genética , Proteína p53 Supresora de Tumor/genética , Ensayos Antitumor por Modelo de Xenoinjerto

RESUMEN

Bone formation and osteoblast differentiation require the functional expression of the Runx2/Cbfbeta heterodimeric transcription factor complex. Runx2 is also a suppressor of proliferation in osteoblasts by attenuating cell cycle progression in G(1). Runx2 levels are modulated during the cell cycle, which are maximal in G(1) and minimal beyond the G(1)/S phase transition (S, G(2), and M phases). It is not known whether Cbfbeta gene expression is cell cycle controlled in preosteoblasts nor how Runx2 or Cbfbeta are regulated during the cell cycle in bone cancer cells. We investigated Runx2 and Cbfbeta gene expression during cell cycle progression in MC3T3-E1 osteoblasts, as well as ROS17/2.8 and SaOS-2 osteosarcoma cells. Runx2 protein levels are reduced as expected in MC3T3-E1 cells arrested in late G(1) (by mimosine) or M phase (by nocodazole), but not in cell cycle arrested osteosarcoma cells. Cbfbeta protein levels are cell cycle independent in both osteoblasts and osteosarcoma cells. In synchronized MC3T3-E1 osteoblasts progressing from late G1 or mitosis, Runx2 levels but not Cbfbeta levels are cell cycle regulated. However, both factors are constitutively elevated throughout the cell cycle in osteosarcoma cells. Proteasome inhibition by MG132 stabilizes Runx2 protein levels in late G(1) and S in MC3T3-E1 cells, but not in ROS17/2.8 and SaOS-2 osteosarcoma cells. Thus, proteasomal degradation of Runx2 is deregulated in osteosarcoma cells. We propose that cell cycle control of Runx2 gene expression is impaired in osteosarcomas and that this deregulation may contribute to the pathogenesis of osteosarcoma.

Asunto(s)

Ciclo Celular/fisiología , Subunidad alfa 1 del Factor de Unión al Sitio Principal/metabolismo , Subunidad beta del Factor de Unión al Sitio Principal/metabolismo , Regulación Neoplásica de la Expresión Génica/fisiología , Osteosarcoma/metabolismo , Animales , Línea Celular , Línea Celular Tumoral , Subunidad alfa 1 del Factor de Unión al Sitio Principal/genética , Subunidad beta del Factor de Unión al Sitio Principal/genética , Inhibidores de Cisteína Proteinasa , Fase G1/fisiología , Expresión Génica/genética , Humanos , Leupeptinas/farmacología , Ratones , Mitosis/fisiología , Osteoblastos/citología , Osteoblastos/metabolismo , Osteosarcoma/patología , Complejo de la Endopetidasa Proteasomal/metabolismo , Inhibidores de Proteasoma , Ratas , Ubiquitinación/efectos de los fármacos

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BACKGROUND: Previous studies highlight the risk of valgus ankle instability in children following vascularized fibular procedures. We have observed that persistent valgus instability results in valgus deformity in these ankles. The aim of this study was to explore the risk factors associated with valgus ankle deformity following vascularized fibular graft harvest. METHODS: We present 31 patients with minimum follow-up of 2 years and maximum of 18 years. They underwent regular clinical evaluation of their ankles and routine radiological evaluation when valgus deformity became clinically apparent. RESULTS: Five patients developed valgus ankle deformities. Risk factors for development of valgus deformity included age under 14 years (P = 0.02) and short [6 +/- standard deviation (SD) 1 cm] residual fibular lengths (P = 0.02). Age-residual fibula index (age in years plus residual distal fibula length in centimeters) under 16 strongly predicted the development of ankle deformity (P = 0.0008). Short residual fibular lengths were not consistently associated with valgus deformity. Children developed focal lateral tibial epiphyseal atrophy and premature antero-medial fusion of the distal fibular physis resulting in a concave-anterior bowing of the fibula. Skeletally mature patients had congruent joints and posterior rotation of the proximal fibula without bowing. CONCLUSIONS: Mechanical causes cannot solely explain valgus ankle deformity following vascularized fibula harvest. Secondary changes due to growth arrest in the ankle significantly contribute to this deformity.

Asunto(s)

Articulación del Tobillo , Peroné/trasplante , Inestabilidad de la Articulación/etiología , Procedimientos Ortopédicos/efectos adversos , Sarcoma/cirugía , Neoplasias de los Tejidos Blandos/cirugía , Adolescente , Adulto , Anciano , Niño , Preescolar , Estudios de Cohortes , Femenino , Peroné/irrigación sanguínea , Estudios de Seguimiento , Humanos , Inestabilidad de la Articulación/diagnóstico por imagen , Inestabilidad de la Articulación/fisiopatología , Masculino , Persona de Mediana Edad , Radiografía , Procedimientos de Cirugía Plástica/efectos adversos , Estudios Retrospectivos , Factores de Riesgo , Adulto Joven

RESUMEN

Heparan sulfate proteoglycans cooperate with basic fibroblast growth factor (bFGF/FGF2) signaling to control osteoblast growth and differentiation, as well as metabolic functions of osteoblasts. FGF2 signaling modulates the expression and activity of Runt-related transcription factor 2 (Runx2/Cbfa1), a key regulator of osteoblast proliferation and maturation. Here, we have characterized novel Runx2 target genes in osteoprogenitors under conditions that promote growth arrest while not yet permitting sustained phenotypic maturation. Runx2 enhances expression of genes related to proteoglycan-mediated signaling, including FGF receptors (e.g., FGFR2 and FGFR3) and proteoglycans (e.g., syndecans [Sdc1, Sdc2, Sdc3], glypicans [Gpc1], versican [Vcan]). Runx2 increases expression of the glycosyltransferase Exostosin-1 (Ext1) and heparanase, as well as alters the relative expression of N-linked sulfotransferases (Ndst1 = Ndst2 > Ndst3) and enzymes mediating O-linked sulfation of heparan sulfate (Hs2st > Hs6st) or chondroitin sulfate (Cs4st > Cs6st). Runx2 cooperates with FGF2 to induce expression of Sdc4 and the sulfatase Galns, but Runx2 and FGF2 suppress Gpc6, thus suggesting intricate Runx2 and FGF2 dependent changes in proteoglycan utilization. One functional consequence of Runx2 mediated modulations in proteoglycan-related gene expression is a change in the responsiveness of bone markers to FGF2 stimulation. Runx2 and FGF2 synergistically enhance osteopontin expression (>100 fold), while FGF2 blocks Runx2 induction of alkaline phosphatase. Our data suggest that Runx2 and the FGF/proteoglycan axis may form an extracellular matrix (ECM)-related regulatory feed-back loop that controls osteoblast proliferation and execution of the osteogenic program.

Asunto(s)

Subunidad alfa 1 del Factor de Unión al Sitio Principal/metabolismo , Factores de Crecimiento de Fibroblastos/metabolismo , Regulación de la Expresión Génica , Osteoblastos/metabolismo , Osteogénesis/fisiología , Proteoglicanos/metabolismo , Animales , Western Blotting , Diferenciación Celular/fisiología , Retroalimentación Fisiológica , Ratones , Análisis de Secuencia por Matrices de Oligonucleótidos , Osteoblastos/citología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transducción de Señal/fisiología , Células Madre/citología , Células Madre/metabolismo

RESUMEN

PURPOSE: We have previously shown that osteosarcomas have states of increased interstitial fluid pressure (IFP) which correlate with increased proliferation and chemosensitivity. In this study, we hypothesized that constitutively raised IFP in osteosarcomas regulates angiogenesis. MATERIALS AND METHODS: Sixteen patients with the clinical diagnosis of osteosarcomas underwent blood fl ow and IFP readings by the wick-in-needle method at the time and location of open biopsy. Vascularity was determined by capillary density in the biopsy specimens. We performed digital image analysis of immunohistochemical staining for CD31, VEGF-A, VEGF-C and TPA on paraffin-embedded tissue blocks of the biopsy samples. Clinical results were validated in a pressurised cell culture system. RESULTS: IFPs in the tumours (mean 33.5 +/- SD 17.2 mmHg) were significantly higher (P = 0.00001) than that in normal tissue (2.9 +/- 5.7 mmHg). Pressure readings were significantly higher in low vascularity tumours compared to high vascularity tumours (P <0.001). In the osteosarcoma cell lines, growth in a pressurised environment was associated with VEGF-A downregulation, VEGF-C upregulation and TPA upregulation. The reverse was seen in the OB cell lines. Growth in the HUVEC cell line was not significantly inhibited in a pressurised environment. Immunohistochemical assessment for VEGF-A (P = 0.01), VEGF-C (P = 0.008) and TPA (P = 0.0001) translation were consistent with the findings on PCR. CONCLUSION: Our data suggest that some molecules in angiogenesis are regulated by changes in IFP.

Asunto(s)

Proteínas Angiogénicas/fisiología , Neoplasias Óseas/irrigación sanguínea , Líquido Extracelular/fisiología , Osteosarcoma/irrigación sanguínea , Adolescente , Células Cultivadas , Femenino , Humanos , Masculino , Neovascularización Patológica , Presión

RESUMEN

To understand the molecular etiology of osteosarcoma, we isolated and characterized a human osteosarcoma cell line (OS1). OS1 cells have high osteogenic potential in differentiation induction media. Molecular analysis reveals OS1 cells express the pocket protein pRB and the runt-related transcription factor Runx2. Strikingly, Runx2 is expressed at higher levels in OS1 cells than in human fetal osteoblasts. Both pRB and Runx2 have growth suppressive potential in osteoblasts and are key factors controlling competency for osteoblast differentiation. The high levels of Runx2 clearly suggest osteosarcomas may form from committed osteoblasts that have bypassed growth restrictions normally imposed by Runx2. Interestingly, OS1 cells do not exhibit p53 expression and thus lack a functional p53/p21 DNA damage response pathway as has been observed for other osteosarcoma cell types. Absence of this pathway predicts genomic instability and/or vulnerability to secondary mutations that may counteract the anti-proliferative activity of Runx2 that is normally observed in osteoblasts. We conclude OS1 cells provide a valuable cell culture model to examine molecular events that are responsible for the pathologic conversion of phenotypically normal osteoblast precursors into osteosarcoma cells.

Asunto(s)

Subunidad alfa 1 del Factor de Unión al Sitio Principal/genética , Regulación del Desarrollo de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Osteosarcoma/genética , Proteína de Retinoblastoma/genética , Línea Celular Transformada , Línea Celular Tumoral , Proliferación Celular , Subunidad alfa 1 del Factor de Unión al Sitio Principal/metabolismo , Ciclina D , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/metabolismo , Ciclinas/metabolismo , Humanos , Microscopía Fluorescente , Osteoblastos/metabolismo , Osteoblastos/ultraestructura , Osteosarcoma/metabolismo , Proteína de Retinoblastoma/metabolismo , Transducción de Señal , Estadísticas no Paramétricas , Proteína p53 Supresora de Tumor/metabolismo

RESUMEN

<p><b>PURPOSE</b>We have previously shown that osteosarcomas have states of increased interstitial fluid pressure (IFP) which correlate with increased proliferation and chemosensitivity. In this study, we hypothesized that constitutively raised IFP in osteosarcomas regulates angiogenesis.</p><p><b>MATERIALS AND METHODS</b>Sixteen patients with the clinical diagnosis of osteosarcomas underwent blood fl ow and IFP readings by the wick-in-needle method at the time and location of open biopsy. Vascularity was determined by capillary density in the biopsy specimens. We performed digital image analysis of immunohistochemical staining for CD31, VEGF-A, VEGF-C and TPA on paraffin-embedded tissue blocks of the biopsy samples. Clinical results were validated in a pressurised cell culture system.</p><p><b>RESULTS</b>IFPs in the tumours (mean 33.5 +/- SD 17.2 mmHg) were significantly higher (P = 0.00001) than that in normal tissue (2.9 +/- 5.7 mmHg). Pressure readings were significantly higher in low vascularity tumours compared to high vascularity tumours (P <0.001). In the osteosarcoma cell lines, growth in a pressurised environment was associated with VEGF-A downregulation, VEGF-C upregulation and TPA upregulation. The reverse was seen in the OB cell lines. Growth in the HUVEC cell line was not significantly inhibited in a pressurised environment. Immunohistochemical assessment for VEGF-A (P = 0.01), VEGF-C (P = 0.008) and TPA (P = 0.0001) translation were consistent with the findings on PCR.</p><p><b>CONCLUSION</b>Our data suggest that some molecules in angiogenesis are regulated by changes in IFP.</p>

Asunto(s)

Adolescente , Femenino , Humanos , Masculino , Proteínas Angiogénicas , Fisiología , Neoplasias Óseas , Células Cultivadas , Líquido Extracelular , Fisiología , Neovascularización Patológica , Osteosarcoma , Presión