Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 17 de 17
Filtrar
1.
Dig Dis Sci ; 68(6): 2276-2284, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36725765

RESUMO

BACKGROUND: Per Oral Endoscopic Myotomy (POEM) is a minimally invasive treatment for achalasia with results comparable to laparoscopic Heller myotomy (LHM). Studies have described the development of proficiency for endoscopists learning to perform POEM, and societies have defined educational and technical objectives for advanced endoscopy fellows in training. However, there is limited guidance on the organizational strategy and educational plan necessary to develop an achalasia service with POEM expertise. AIMS: We aim to outline the steps for design and implementation of a successful POEM program. METHODS: We reported our experience developing a multi-disciplinary clinical program for POEM and the steps taken to achieve procedural proficiency. We also reported our technical success (successful tunneling into the gastric cardia and myotomy of LES muscle fibers) and clinical success (post-procedure Eckardt score ≤ 3) at 3-6 months and 12 months post-procedure. Adverse events were classified per the ASGE lexicon for endoscopic adverse events. RESULTS: After creating a multi-disciplinary clinical program for achalasia and completing procedural proficiency for POEM, our technical success rate was 100% and clinical success rate 90% for the first 41 patients. One adverse event (2.4%) occurred, moderate in severity per the American Society of Gastrointestinal Endoscopy (ASGE) lexicon for adverse endoscopic events. CONCLUSION: In this study, we outlined the steps involved to establish a POEM service in a large integrated healthcare system. Prior competency in interventional endoscopy, procedural training models, POEM observation and education, proctorship, and interdisciplinary patient care are recommended.


Assuntos
Acalasia Esofágica , Miotomia de Heller , Miotomia , Cirurgia Endoscópica por Orifício Natural , Humanos , Acalasia Esofágica/cirurgia , Endoscopia Gastrointestinal , Miotomia/métodos , Resultado do Tratamento , Cirurgia Endoscópica por Orifício Natural/métodos , Esfíncter Esofágico Inferior/cirurgia
2.
Gastrointest Endosc ; 92(2): 259-268.e2, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32240684

RESUMO

BACKGROUND AND AIMS: Multiband mucosectomy (MBM) is a widely used technique for the treatment of Barrett's esophagus (BE). However, large multicenter studies enabling a generalizable estimation of the risk of serious adverse events, such as perforation and postprocedural bleeding, are lacking. The aim of this study was to estimate the rate of, and risk factors for, serious adverse events associated with MBM. METHODS: In this retrospective analysis, consecutive patients who underwent MBM for treatment of BE in 14 tertiary referral centers in Europe, the United States, Canada, and Australia were included. Primary outcomes were perforation and postprocedural bleeding rate. Potential risk factors were identified by logistic regression. RESULTS: Between 2001 and 2016, a total of 3827 MBM procedures were performed in 2447 patients (84% male, mean age 66 years, median BE length C2M4). Perforation occurred in 17 procedures (0.4%; 95% confidence interval [CI], 0.3-0.7), of which 15 could be treated endoscopically or conservatively. Female gender was an independent risk factor for perforation (odds ratio [OR], 2.77; 95% CI, 1.02-7.57; P = .05). Postprocedural bleeding occurred after 35 procedures (0.9%; 95% CI, 0.6-1.3). The number of resections (OR, 1.15; 95% CI, 1.06-1.25; P < .001) was significantly associated with postprocedural bleeding. CONCLUSION: The results of this study show that MBM for BE is safe with a low risk of serious adverse events. In addition, most of the adverse events could be managed endoscopically or conservatively. The number of resections was an independent risk factor for postprocedural bleeding.


Assuntos
Esôfago de Barrett , Neoplasias Esofágicas , Idoso , Austrália , Esôfago de Barrett/cirurgia , Canadá , Esofagoscopia , Europa (Continente) , Feminino , Humanos , Masculino , Estudos Retrospectivos , Fatores de Risco
3.
Gastrointest Endosc ; 92(1): 31-39.e1, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-31953189

RESUMO

BACKGROUND AND AIMS: The treatment of submucosal (T1b) esophageal adenocarcinoma (EAC) remains in evolution, with some evidence supporting endoscopic management of low-risk lesions. Using a multicenter cohort, we evaluated outcomes of patients with T1b EAC and predictors of survival. METHODS: Patients diagnosed between 2001 and 2016 with T1b EAC were identified from 3 academic medical centers in the United States. Demographic, clinical, and outcome data were collected. Outcomes studied were overall and cancer-free survival. Cox proportional hazards models were constructed to assess independent predictors of survival. RESULTS: One hundred forty-one patients were included, of whom 68 (48%) underwent esophagectomy and 73 (52%) were treated endoscopically. Most patients (85.8%) had high-risk histologic features. Thirty-day operative mortality was 2.9%. Median follow-up in the esophagectomy and endoscopic cohorts was 49.4 and 43.4 months, respectively. Patients treated endoscopically were older with higher comorbidity scores, with 46 (63%) achieving histologic remission. Nineteen patients (26.0%) also received chemoradiation. Five-year overall survival rates in the surgical and endoscopic cohorts were 89% and 59%, respectively, whereas 5-year cancer-free survival rates were 92% and 69%. Presence of high-risk histologic features was associated with reduced overall survival. CONCLUSIONS: In this large multicenter study of patients with T1b EAC, esophagectomy was associated with improved overall but not cancer-free survival. High-risk histologic features were associated with poorer survival.


Assuntos
Adenocarcinoma , Neoplasias Esofágicas , Adenocarcinoma/patologia , Idoso , Estudos de Coortes , Neoplasias Esofágicas/patologia , Esofagectomia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Estudos Retrospectivos , Estados Unidos
4.
5.
Gastroenterology ; 154(4): 1205-1206, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29452089
7.
Gastrointest Endosc ; 87(1): 104-109.e3, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28499830

RESUMO

BACKGROUND AND AIMS: In 2015, the U.S. Food and Drug Administration and Centers for Disease Control and Prevention (CDC) issued guidance for duodenoscope culturing and reprocessing in response to outbreaks of carbapenem-resistant Enterobacteriaceae (CRE) duodenoscope-related infections. Based on this guidance, we implemented best practices for reprocessing and developed a systematic process for culturing endoscopes with elevator levers. The aim of this study is to report the outcomes and direct costs of this program. METHODS: First, clinical microbiology data from 2011 to 2014 were reviewed retrospectively to assess for possible elevator lever-equipped endoscope-related CRE infections. Second, a program to systematically culture elevator lever-equipped endoscopes was implemented. Each week, about 25% of the inventory of elevator lever-equipped endoscopes is cultured based on the CDC guidelines. If any cultures return bacterial growth, the endoscope is quarantined pending repeat culturing. The costs of the program, including staff time and supplies, have been calculated. RESULTS: From 2011 to 2014, none of 17 patients with documented CRE infection had undergone ERCP or endoscopic ultrasound in the previous 36 months. From June 2015 to September 2016, 285 cultures were performed. Three (1.1%) had bacterial growth, 2 with skin contaminants and 1 with an oral contaminant. The associated endoscopes were quarantined and reprocessed, and repeat cultures were negative. The total estimated cost of our program for an inventory of 20 elevator lever-equipped endoscopes was $30,429.60 per year ($1521.48 per endoscope). CONCLUSIONS: This 16-month evaluation of a systematic endoscope culturing program identified a low rate of positive cultures after elevator lever endoscope reprocessing. All positive cultures were with non-enteric microorganisms. The program was of modest cost and identified reprocessing procedures that may have led to a low rate of positive cultures.


Assuntos
Técnicas de Cultura/métodos , Desinfecção , Endoscópios Gastrointestinais/microbiologia , Contaminação de Equipamentos/prevenção & controle , Reutilização de Equipamento , Colangiopancreatografia Retrógrada Endoscópica , Técnicas de Cultura/economia , Surtos de Doenças , Duodenoscópios/microbiologia , Endossonografia , Infecções por Enterobacteriaceae/epidemiologia , Humanos , Avaliação de Programas e Projetos de Saúde , Estudos Retrospectivos
8.
Ann Hepatol ; 16(6): 924-931, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29055929

RESUMO

INTRODUCTION: Orthotopic liver transplantation anastomotic biliary strictures (OLT ABS) are managed with endoscopic biliary stent therapy but the recurrence rate is substantial. Our aims were to retrospectively determine the recurrence rates of OLT ABS after initial successful stent therapy, characterize the management of recurrences and identify associated variables. MATERIALS AND METHODS: Clinical data from 943 patients receiving non-living donor OLT at our institution from 2005-2012 were reviewed, and 123 OLT ABS patients receiving stent therapy were identified. Features of their endoscopic stent therapy and other pertinent clinical information were evaluated. RESULTS: ABS recurred in 25.5% of patients (24/94) after an initial successful course of stent therapy. Recurrences were received a second course of endoscopic stent therapy and 67% of patients (16/24) achieved long-term remediation of ABS. Six patients underwent a third course of endoscopic stent therapy with 4 patients achieving remediation. Overall remediation rate among ABS recurrences was 83.3% (20/24). A bivariate comparison demonstrated HCV infection, age, median months of maximal stenting and a lower maximum cumulative stent diameter were risk factors for ABS recurrence. Using a Cox regression model, only HCV status proved to be a risk factor for recurrence. DISCUSSION: In conclusion repeat stent therapy achieved high stricture remediation rates. Recurrence after the first or even second course of stenting should not imply failure of endoscopic therapy. A positive HCV status may be associated with higher stricture recurrence rates and this association should be further investigated.


Assuntos
Colangiopancreatografia Retrógrada Endoscópica , Colestase/cirurgia , Transplante de Fígado/efeitos adversos , Adulto , Idoso , Colangiopancreatografia Retrógrada Endoscópica/efeitos adversos , Colangiopancreatografia Retrógrada Endoscópica/instrumentação , Colestase/diagnóstico por imagem , Colestase/etiologia , Constrição Patológica , Feminino , Hepatite C/complicações , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Modelos de Riscos Proporcionais , Recidiva , Estudos Retrospectivos , Fatores de Risco , Stents , Fatores de Tempo , Resultado do Tratamento , Adulto Jovem
9.
Ann Intern Med ; 167(3): 152-158, 2017 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-28672282

RESUMO

BACKGROUND: Clostridium difficile infection (CDI), the most common health care-associated infection, often recurs. Fecal microbiota transplantation is increasingly used to treat multiply recurrent CDI (mrCDI). OBJECTIVE: To determine whether the incidence of mrCDI is increasing in proportion to CDI and to identify risk factors for mrCDI. DESIGN: Retrospective cohort study. SETTING: United States. PARTICIPANTS: 38 911 718 commercially insured patients in the OptumInsight Clinformatics Database, of whom 45 341 developed CDI. MEASUREMENTS: Age- and sex-standardized incidence rates for CDI and mrCDI. RESULTS: From 2001 to 2012, the annual incidence of CDI and mrCDI per 1000 person-years increased by 42.7% (from 0.4408 to 0.6289 case) and 188.8% (from 0.0107 to 0.0309 case), respectively. The increase in mrCDI incidence was independent of known risk factors for CDI. Those who developed mrCDI were older (median age, 56.0 vs. 49.0 years; adjusted odds ratio [aOR] per 10-year increase in age, 1.25 [95% CI, 1.21 to 1.29]) and were more likely to be female (63.8% vs. 58.7%; aOR, 1.24 [CI, 1.11 to 1.38]) and to have used antibiotics (72.3% vs. 58.8%; aOR, 1.79 [CI, 1.59 to 2.01]), proton-pump inhibitors (24.6% vs. 18.2%; aOR, 1.14 [CI, 1.01 to 1.29]), or corticosteroids (18.3% vs. 13.7%; aOR, 1.15 [CI, 1.00 to 1.32]) within 90 days of CDI diagnosis. Chronic kidney disease (10.4% vs. 5.6%; aOR, 1.49 [CI, 1.24 to 1.80]) and diagnosis in a nursing home (2.1% vs. 0.6%; aOR, 1.99 [CI, 1.34 to 2.93]) were also associated with increased risk for mrCDI. LIMITATION: The primary analyses included only commercially insured patients in the United States. CONCLUSION: Relative to CDI, mrCDI incidence has disproportionately increased, indicating a rising demand for mrCDI therapies. PRIMARY FUNDING SOURCE: National Institute of Diabetes and Digestive and Kidney Diseases and National Institute of Allergy and Infectious Diseases.


Assuntos
Clostridioides difficile , Infecções por Clostridium/epidemiologia , Adolescente , Adulto , Infecções por Clostridium/terapia , Transplante de Microbiota Fecal , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Recidiva , Estudos Retrospectivos , Fatores de Risco , Estados Unidos/epidemiologia , Adulto Jovem
10.
Gastrointest Endosc Clin N Am ; 27(3): 481-490, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28577769

RESUMO

Radiofrequency ablation (RFA) is a safe and effective thermal ablative therapy for dysplastic Barrett's esophagus (BE) and, to a lesser extent, nondysplastic BE. Before the utilization of RFA, there must be an appropriate indication, assessment of potential contraindications, discussion of risks and benefits with patients, and careful endoscopic planning. The ease of performance of the procedure along with its efficacy and low rate of adverse events have established RFA as a reliable technique for endoscopic management of dysplastic BE.


Assuntos
Esôfago de Barrett/cirurgia , Ablação por Cateter/métodos , Seleção de Pacientes , Lesões Pré-Cancerosas/cirurgia , Esôfago de Barrett/patologia , Esofagoscopia , Esôfago/patologia , Humanos , Lesões Pré-Cancerosas/patologia , Resultado do Tratamento
11.
J Am Coll Surg ; 223(5): 729-737.e1, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27497827

RESUMO

BACKGROUND: In 2015, the American Gastroenterological Association (AGA) published guidelines to provide recommendations for management of suspected pancreatic cystic neoplasms (PCNs). The aim of this study was to compare efficacy of these with the Fukuoka consensus guidelines in predicting advanced neoplasia (AN) in patients with suspected PCNs. STUDY DESIGN: We performed a retrospective study of 239 patients who underwent surgical resection for suspected mucinous PCN at a tertiary care center from 2000 to 2014. Surgical pathology was the gold standard. The AGA and Fukuoka criteria were applied, and their performance in predicting AN, defined as invasive cancer or high-grade dysplasia (HGD), was assessed. RESULTS: Advanced neoplasia was found in 71 of 239 (29.7%) patients (28 invasive cancer, 43 HGD). The Fukuoka "high-risk" (FG-HR) and AGA "high-risk" (AGA-HR) criteria identified patients with AN with sensitivities of 28.2% and 35.2%, specificities of 95.8% and 94.0%, positive predictive values of 74.1% and 71.4%, and negative predictive values of 75.9% and 77.5%, respectively. Overall, there was no significant difference between the guidelines for prediction of AN. There were 7 and 6 cases with invasive cancer, and 23 and 24 cases with HGD missed by the FG-HR and AGA-HR guidelines, respectively. CONCLUSIONS: In a retrospective analysis, the AGA guidelines are not superior to the Fukuoka guidelines in identifying AN in suspected PCNs. Both sets of guidelines have fair PPV for detection of AN, which would lead to avoidable resections in patients without AN. Additionally, the high-risk features of both guidelines do not accurately identify all patients with AN.


Assuntos
Cisto Pancreático/diagnóstico , Cisto Pancreático/patologia , Neoplasias Pancreáticas/diagnóstico , Neoplasias Pancreáticas/patologia , Guias de Prática Clínica como Assunto , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Invasividade Neoplásica , Cisto Pancreático/cirurgia , Neoplasias Pancreáticas/cirurgia , Valor Preditivo dos Testes , Estudos Retrospectivos , Sensibilidade e Especificidade
12.
Gastroenterology ; 151(2): 288-297.e4, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27215656

RESUMO

BACKGROUND & AIMS: Rectal indomethacin reduces the risk of pancreatitis after endoscopic retrograde cholangiopancreatography (ERCP). Most studies of its efficacy included high-risk cohorts and excluded low-risk patients, including those with malignant biliary obstruction. We investigated the potential of rectal indomethacin to prevent post-ERCP pancreatitis (PEP) in a variety of patients. METHODS: We performed a retrospective cohort study of 4017 patients who underwent ERCP at the Hospital of the University of Pennsylvania, from 2009 and 2015, including 823 patients with malignant biliary obstruction. After June 2012, with a few exceptions, patients received indomethacin after their procedure. We collected data from patients' records on demographic and clinical features, procedures, and development of PEP. PEP was defined by consensus criteria. Multivariable logistic regression was used to determine adjusted odds ratios (ORs) for the association between indomethacin and PEP. RESULTS: Rectal indomethacin reduced the odds of PEP by 65% (OR, 0.35; 95% confidence interval [CI], 0.24-0.51; P < .001) and moderate-to-severe PEP by 83% (OR, 0.17; 95% CI, 0.09-0.32; P < .001). In patients with malignant obstruction, rectal indomethacin reduced the risk of PEP by 64% (OR, 0.36; 95% CI, 0.17-0.75; P < .001) and moderate-to-severe PEP by 80% (OR, 0.20; 95% CI, 0.07-0.63; P < .001). Among patients with malignant obstruction, rectal indomethacin provided the greatest benefit to patients with pancreatic adenocarcinoma: 2.31% of these patients who received rectal indomethacin developed PEP vs 7.53% who did not receive rectal indomethacin (P < .001) and 0.59% of these patients who received rectal indomethacin developed moderate-to-severe PEP vs 4.32% who did not receive rectal indomethacin (P = .001). CONCLUSIONS: In a large retrospective cohort study of patients undergoing ERCP that included low-risk patients and patients with malignant biliary obstruction, rectal indomethacin was associated with a significant decrease in the absolute rate and severity of pancreatitis.


Assuntos
Anti-Inflamatórios não Esteroides/administração & dosagem , Colangiopancreatografia Retrógrada Endoscópica/efeitos adversos , Indometacina/administração & dosagem , Pancreatite/prevenção & controle , Complicações Pós-Operatórias/prevenção & controle , Administração Retal , Adulto , Idoso , Colangiopancreatografia Retrógrada Endoscópica/métodos , Feminino , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Pancreatite/etiologia , Complicações Pós-Operatórias/etiologia , Estudos Retrospectivos , Fatores de Risco , Resultado do Tratamento
13.
Clin Gastroenterol Hepatol ; 12(10): 1624-34.e1, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24534546

RESUMO

BACKGROUND & AIMS: A valid risk prediction model for colorectal neoplasia would allow patients to be screened for colorectal cancer (CRC) on the basis of risk. We performed a systematic review of studies reporting risk prediction models for colorectal neoplasia. METHODS: We conducted a systematic search of MEDLINE, Scopus, and Cochrane Library databases from January 1990 through March 2013 and of references in identified studies. Case-control, cohort, and cross-sectional studies that developed or attempted to validate a model to predict risk of colorectal neoplasia were included. Two reviewers independently extracted data and assessed model quality. Model quality was considered to be good for studies that included external validation, fair for studies that included internal validation, and poor for studies with neither. RESULTS: Nine studies developed a new prediction model, and 2 tested existing models. The models varied with regard to population, predictors, risk tiers, outcomes (CRC or advanced neoplasia), and range of predicted risk. Several included age, sex, smoking, a measure of obesity, and/or family history of CRC among the predictors. Quality was good for 6 models, fair for 2 models, and poor for 1 model. The tier with the largest population fraction (low, intermediate, or high risk) depended on the model. For most models that defined risk tiers, the risk difference between the highest and lowest tier ranged from 2-fold to 4-fold. Two models reached the 0.70 threshold for the C statistic, typically considered to indicate good discriminatory power. CONCLUSIONS: Most current colorectal neoplasia risk prediction models have relatively weak discriminatory power and have not demonstrated generalizability. It remains to be determined how risk prediction models could inform CRC screening strategies.


Assuntos
Neoplasias Colorretais/diagnóstico , Detecção Precoce de Câncer/métodos , Detecção Precoce de Câncer/estatística & dados numéricos , Medicina de Precisão/métodos , Humanos , Medição de Risco/métodos
14.
Dev Biol ; 347(2): 325-36, 2010 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-20816797

RESUMO

Heart valve malformations are one of the most common types of birth defects, illustrating the complex nature of valve development. Vascular endothelial growth factor (VEGF) signaling is one pathway implicated in valve formation, however its specific spatial and temporal roles remain poorly defined. To decipher these contributions, we use two inducible dominant negative approaches in mice to disrupt VEGF signaling at different stages of embryogenesis. At an early step in valve development, VEGF signals are required for the full transformation of endocardial cells to mesenchymal cells (EMT) at the outflow tract (OFT) but not atrioventricular canal (AVC) endocardial cushions. This role likely involves signaling mediated by VEGF receptor 1 (VEGFR1), which is highly expressed in early cushion endocardium before becoming downregulated after EMT. In contrast, VEGFR2 does not exhibit robust cushion endocardium expression until after EMT is complete. At this point, VEGF signaling acts through VEGFR2 to direct the morphogenesis of the AVC cushions into mature, elongated valve leaflets. This latter role of VEGF requires the VEGF-modulating microRNA, miR-126. Thus, VEGF roles in the developing valves are dynamic, transitioning from a differentiation role directed by VEGFR1 in the OFT to a morphogenetic role through VEGFR2 primarily in the AVC-derived valves.


Assuntos
Valvas Cardíacas/embriologia , Fator A de Crescimento do Endotélio Vascular/fisiologia , Animais , Padronização Corporal/genética , Padronização Corporal/fisiologia , Endocárdio/embriologia , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Mesoderma/embriologia , Camundongos , Camundongos Transgênicos , MicroRNAs/genética , Modelos Cardiovasculares , Gravidez , Transdução de Sinais/genética , Transdução de Sinais/fisiologia , Fator A de Crescimento do Endotélio Vascular/genética , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/genética , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/fisiologia , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/genética , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/fisiologia
15.
J Biomed Mater Res A ; 94(1): 234-40, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20166219

RESUMO

Periprosthetic osteolysis of joint replacements caused by wear debris is a significant complication of joint replacements. Polymethylmethacrylate (PMMA) particles have been shown to inhibit osteogenic differentiation, but the molecular mechanism has not been previously determined. In this study, we exposed differentiating MC3T3-E1 preostoblast cells to PMMA particles and determined the changes that occurred with respect to p38 mitogen-activated protein kinase (MAPK) activity and the transforming growth factor (TGF)-beta1 and bone morphogenetic protein (BMP) signaling pathways. In the absence of particles, MC3T3-E1 cells demonstrate activation of p38 MAPK on day 8 of differentiation; however, when treated with PMMA particles, differentiating MC3T3-E1 cells demonstrate the suppression of p38 activity on day 8 and show activation of p38 on days 1 and 4. On day 4 of particle exposure, the differentiating MC3T3-E1 cells show significant downregulation of TGF-beta1 expression, which is involved in osteoblast differentiation, and a significant upregulation of the expression of BMP3 and Sclerostin (SOST), which are negative regulators of osteoblast differentiation. By day 8 of particle exposure, the changes in TGF-beta1, BMP3, and SOST expression are opposite of those seen on day 4. This study has demonstrated the distinct changes in the molecular profile of MC3T3-E1 cells during particle-induced inhibition of osteoblast differentiation. (c) 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010.


Assuntos
Cimentos Ósseos/farmacologia , Diferenciação Celular/efeitos dos fármacos , Polimetil Metacrilato/farmacologia , Transdução de Sinais/efeitos dos fármacos , Fator de Crescimento Transformador beta/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Células 3T3 , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Biomarcadores/metabolismo , Proteínas Morfogenéticas Ósseas/metabolismo , Diferenciação Celular/fisiologia , Ativação Enzimática , Expressão Gênica/efeitos dos fármacos , Teste de Materiais , Camundongos , Tamanho da Partícula , Polimetil Metacrilato/química
16.
J Orthop Res ; 28(5): 571-7, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20014320

RESUMO

Polymethylmethacrylate (PMMA) particles have been shown to inhibit the differentiation of osteoprogenitor cells, but the mechanism of this inhibitory effect has not been investigated. We hypothesize that the inhibitory effects of PMMA particles involve impairment of osteoprogenitor viability and direct inhibition of transcription factors that regulate osteogenesis. We challenged MC3T3-E1 osteoprogenitors with PMMA particles and examined the effects of these materials on osteoprogenitor viability and expression of transcription factors Runx2, osterix, Dlx5, and Msx2. MC3T3-E1 cells treated with PMMA particles over a 72-h period showed a significant reduction in cell viability and proliferation as indicated by a dose- and time-dependent increase in supernatant levels of lactate dehydrogenase, an intracellular enzyme released from dead cells, a dose-dependent decrease in cell number and BrdU uptake, and the presence of large numbers of positively labeled Annexin V-stained cells. The absence of apoptotic cells on TUNEL assay indicated that cell death occurred by necrosis, not apoptosis. MC3T3-E1 cells challenged with PMMA particles during the first 6 days of differentiation in osteogenic medium showed a significant dose-dependent decrease in the RNA expression of Runx2, osterix, and Dlx5 on all days of measurement, while the RNA expression of Msx2, an antagonist of Dlx5-induced osteogenesis, remained relatively unaffected. These results indicate that PMMA particles impair osteoprogenitor viability and inhibit the expression of transcription factors that promote osteoprogenitor differentiation.


Assuntos
Subunidade alfa 1 de Fator de Ligação ao Core/genética , Proteínas de Homeodomínio/genética , Osteócitos/citologia , Polimetil Metacrilato/toxicidade , Células-Tronco/efeitos dos fármacos , Fatores de Transcrição/genética , Células 3T3 , Animais , Anexina A5/metabolismo , Apoptose/efeitos dos fármacos , Cimentos Ósseos/toxicidade , Reabsorção Óssea/induzido quimicamente , Reabsorção Óssea/fisiopatologia , Diferenciação Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Expressão Gênica/efeitos dos fármacos , Camundongos , Falha de Prótese , RNA Mensageiro/metabolismo , Fator de Transcrição Sp7 , Células-Tronco/citologia , Células-Tronco/fisiologia
17.
Proc Natl Acad Sci U S A ; 104(32): 13040-5, 2007 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-17666529

RESUMO

Transcriptional control by beta-catenin and lymphoid enhancer-binding factor 1 (LEF1)/T cell factor regulates proliferation in stem cells and tumorigenesis. Here we provide evidence that transcriptional co repressor homeodomain interacting protein kinase 2 (HIPK2) controls the number of stem and progenitor cells in the skin and the susceptibility to develop squamous cell carcinoma. Loss of HIPK2 leads to increased proliferative potential, more rapid G1-S transition in cell cycle, and expansion of the epidermal stem cell compartment. Among the critical regulators of G1-S transition in the cell cycle, only cyclin D1 is selectively up-regulated in cells lacking HIPK2. Conversely, overexpression of HIPK2 suppresses LEF1/beta-catenin-mediated transcriptional activation of cyclin D1 expression. However, deletion of the C-terminal YH domain of HIPK2 completely abolishes its ability to recruit another transcriptional corepressor CtBP and suppress LEF1/beta-catenin-mediated transcription. To determine whether loss of HIPK2 leads to increased susceptibility to tumorigenesis, we treat wild-type, Hipk2+/-, andHipk2-/- mice with the two-stage carcinogenesis protocol. Our results indicate that more skin tumors are induced in Hipk2+/- and Hipk2-/- mutants, with most of the tumors showing shortened incubation time and malignant progression. Together, our results indicate that HIPK2 is a tumor suppressor that controls proliferation by antagonizing LEF1/beta-catenin-mediated transcription. Loss of HIPK2 synergizes with activation of H-ras to induce tumorigenesis.


Assuntos
Proteínas de Transporte/fisiologia , Células Epidérmicas , Proteínas Serina-Treonina Quinases/fisiologia , Proteínas Repressoras/fisiologia , Neoplasias Cutâneas/prevenção & controle , Células-Tronco/citologia , beta Catenina/fisiologia , Animais , Proliferação de Células , Células Cultivadas , Ciclina D1/genética , Queratinócitos/patologia , Fator 1 de Ligação ao Facilitador Linfoide/fisiologia , Camundongos , Ativação Transcricional
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...