Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 63
Filtrar
1.
J Radiol Case Rep ; 17(9): 22-28, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38098960

RESUMO

A 51-year-old female patient was presenting dyspnea for more than a year with no previous lung infections or surgery. Initially, a diagnostic computed tomography was made, showing a rare arterio-arterial malformation between the right inferior phrenic and right pulmonary artery leading into a vascular bundle in the middle lung lobe. Due to the patients' dyspnea and massive extent of malformation, the indication for transcatheter arterial embolization was made. The first transcatheter arterial embolization procedure involved the inferior phrenic and a selective branch of the internal thoracic artery. Interventional angiography as well as computed tomography revealed further extend of the malformation showing a connection of right lateral thoracic, hepatic, and inferior epigastric artery to the fistula. After one month, a second transcatheter arterial embolization of these arteries as well as a second approach of the proximal internal thoracic artery was performed. In the follow-up the patient described a substantial improvement of her dyspnea and showed no signs of infections. A phrenic artery to pulmonary artery fistula is an extremely rare case occurring congenital or acquired. Patients may be asymptomatic or present, among others, dyspnea, hemoptysis, pulmonary infections and congestive heart failure. Symptomatic patients require treatment using transcatheter arterial embolization or surgical resection. The patient had dyspnea and a substantial extent of malformation with possibly complicated clinical course. The recommended less invasive treatment using transcatheter arterial embolization was successfully performed. In conclusion, our patient represented a rare congenital case of systemic and pulmonary artery communication, which we were able to treat sufficiently with coil embolization.


Assuntos
Embolização Terapêutica , Fístula , Feminino , Humanos , Pessoa de Meia-Idade , Artéria Pulmonar/diagnóstico por imagem , Artéria Pulmonar/anormalidades , Pulmão , Angiografia , Dispneia/etiologia , Embolização Terapêutica/métodos
2.
Clin Oncol (R Coll Radiol) ; 35(5): e312-e318, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36804153

RESUMO

AIMS: Intrahepatic cholangiocarcinoma (iCCA) and hepatocellular carcinoma (HCC) differ in prognosis and treatment. We aimed to non-invasively differentiate iCCA and HCC by means of radiomics extracted from contrast-enhanced standard-of-care computed tomography (CT). MATERIALS AND METHODS: In total, 94 patients (male, n = 68, mean age 63.3 ± 12.4 years) with histologically confirmed iCCA (n = 47) or HCC (n = 47) who underwent contrast-enhanced abdominal CT between August 2014 and November 2021 were retrospectively included. The enhancing tumour border was manually segmented in a clinically feasible way by defining three three-dimensional volumes of interest per tumour. Radiomics features were extracted. Intraclass correlation analysis and Pearson metrics were used to stratify robust and non-redundant features with further feature reduction by LASSO (least absolute shrinkage and selection operator). Independent training and testing datasets were used to build four different machine learning models. Performance metrics and feature importance values were computed to increase the models' interpretability. RESULTS: The patient population was split into 65 patients for training (iCCA, n = 32) and 29 patients for testing (iCCA, n = 15). A final combined feature set of three radiomics features and the clinical features age and sex revealed a top test model performance of receiver operating characteristic (ROC) area under the curve (AUC) = 0.82 (95% confidence interval =0.66-0.98; train ROC AUC = 0.82) using a logistic regression classifier. The model was well calibrated, and the Youden J Index suggested an optimal cut-off of 0.501 to discriminate between iCCA and HCC with a sensitivity of 0.733 and a specificity of 0.857. CONCLUSIONS: Radiomics-based imaging biomarkers can potentially help to non-invasively discriminate between iCCA and HCC.


Assuntos
Neoplasias dos Ductos Biliares , Carcinoma Hepatocelular , Colangiocarcinoma , Neoplasias Hepáticas , Humanos , Masculino , Pessoa de Meia-Idade , Idoso , Carcinoma Hepatocelular/diagnóstico por imagem , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/patologia , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/métodos , Colangiocarcinoma/diagnóstico por imagem , Neoplasias dos Ductos Biliares/diagnóstico por imagem , Ductos Biliares Intra-Hepáticos/diagnóstico por imagem , Ductos Biliares Intra-Hepáticos/patologia
4.
Breast Cancer Res ; 20(1): 67, 2018 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-29976237

RESUMO

BACKGROUND: Circulating tumor cells (CTCs) are the major players in the metastatic process. A potential mechanism of cell migration and invasion is the formation of microtentacles in tumor cells. These structures are supported by α-tubulin (TUB), detyrosinated α-tubulin (GLU), and vimentin (VIM). In the current study, we evaluated the expression of those cytoskeletal proteins in CTCs. METHODS: Forty patients with breast cancer (BC) (16 early and 24 metastatic) were enrolled in the study. CTCs were isolated using the ISET platform and stained with the following combinations of antibodies: pancytokeratin (CK)/VIM/TUB and CK/VIM/GLU. Samples were analyzed with the ARIOL platform and confocal laser scanning microscopy. RESULTS: Fluorescence quantification revealed that the ratios CK/TUB, CK/VIM, and CK/GLU were statistically increased in MCF7 compared with more aggressive cell lines (SKBR3 and MDA-MB-231). In addition, all of these ratios were statistically increased in MCF7 cells compared with metastatic BC patients' CTCs (p = 0.0001, p = 0.0001, and p = 0.003, respectively). Interestingly, intercellular connections among CTCs and between CTCs and blood cells through cytoskeleton bridges were revealed, whereas microtentacles were increased in patients with CTC clusters. These intercellular connections were supported by TUB, VIM, and GLU. Quantification of the examined molecules revealed that the median intensity of TUB, GLU, and VIM was significantly increased in patients with metastatic BC compared with those with early disease (TUB, 62.27 vs 11.5, p = 0.0001; GLU, 6.99 vs 5.29, p = 0.029; and VIM, 8.24 vs 5.38, p = 0.0001, respectively). CONCLUSIONS: CTCs from patients with BC aggregate to each other and to blood cells through cytoskeletal protrusions, supported by VIM, TUB, and GLU. Quantification of these molecules could potentially identify CTCs related to more aggressive disease.


Assuntos
Neoplasias da Mama/genética , Citoesqueleto/genética , Tubulina (Proteína)/genética , Vimentina/genética , Adulto , Idoso , Biomarcadores Tumorais/sangue , Neoplasias da Mama/sangue , Neoplasias da Mama/patologia , Movimento Celular/genética , Transição Epitelial-Mesenquimal/genética , Feminino , Humanos , Células MCF-7 , Microscopia Confocal , Pessoa de Meia-Idade , Células Neoplásicas Circulantes , Tubulina (Proteína)/sangue , Tirosina/genética , Vimentina/sangue
5.
Clin Radiol ; 73(9): 833.e19-833.e27, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29884524

RESUMO

AIM: To investigate the impact of noise-optimised virtual monoenergetic imaging (VMI+) reconstructions on quantitative and qualitative image parameters in patients with malignant lymphoma at dual-energy computed tomography (DECT) examinations of the abdomen. MATERIALS AND METHODS: Thirty-five consecutive patients (mean age, 53.8±18.6 years; range, 21-82 years) with histologically proven malignant lymphoma of the abdomen were included retrospectively. Images were post-processed with standard linear blending (M_0.6), traditional VMI, and VMI+ technique at energy levels ranging from 40 to 100 keV in 10 keV increments. Signal-to-noise (SNR) and contrast-to-noise ratios (CNR) were objectively measured in lymphoma lesions. Image quality, lesion delineation, and image noise were rated subjectively by three blinded observers using five-point Likert scales. RESULTS: Quantitative image quality parameters peaked at 40-keV VMI+ (SNR, 15.77±7.74; CNR, 18.27±8.04) with significant differences compared to standard linearly blended M_0.6 (SNR, 7.96±3.26; CNR, 13.55±3.47) and all traditional VMI series (p<0.001). Qualitative image quality assessment revealed significantly superior ratings for image quality at 60-keV VMI+ (median, 5) in comparison with all other image series (p<0.001). Assessment of lesion delineation showed the highest rating scores for 40-keV VMI+ series (median, 5), while lowest subjective image noise was found for 100-keV VMI+ reconstructions (median, 5). CONCLUSION: Low-keV VMI+ reconstructions led to improved image quality and lesion delineation of malignant lymphoma lesions compared to standard image reconstruction and traditional VMI at abdominal DECT examinations.


Assuntos
Abdome/diagnóstico por imagem , Linfoma/diagnóstico por imagem , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Imagem Radiográfica a Partir de Emissão de Duplo Fóton/métodos , Tomografia Computadorizada por Raios X/métodos , Abdome/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Meios de Contraste , Feminino , Humanos , Iopamidol/análogos & derivados , Linfoma/patologia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Razão Sinal-Ruído
6.
Eur Biophys J ; 42(5): 383-94, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23504046

RESUMO

Since the cytoskeleton is known to regulate many cell functions, an increasing amount of effort to characterize cells by their mechanical properties has occured. Despite the structural complexity and dynamics of the multicomponent cytoskeleton, mechanical measurements on single cells are often fit to simple models with two to three parameters, and those parameters are recorded and reported. However, different simple models are likely needed to capture the distinct mechanical cell states, and additional parameters may be needed to capture the ability of cells to actively deform. Our new approach is to capture a much larger set of possibly redundant parameters from cells' mechanical measurement using multiple rheological models as well as dynamic deformation and image data. Principal component analysis and network-based approaches are used to group parameters to reduce redundancies and develop robust biomechanical phenotyping. Network representation of parameters allows for visual exploration of cells' complex mechanical system, and highlights unexpected connections between parameters. To demonstrate that our biomechanical phenotyping approach can detect subtle mechanical differences, we used a Microfluidic Optical Cell Stretcher to mechanically stretch circulating human breast tumor cells bearing genetically-engineered alterations in c-src tyrosine kinase activation, which is known to influence reattachment and invasion during metastasis.


Assuntos
Fenômenos Biofísicos , Fenômenos Mecânicos , Fenótipo , Fenômenos Biomecânicos , Linhagem Celular Tumoral , Sobrevivência Celular , Ativação Enzimática , Humanos , Fenômenos Ópticos , Reologia , Quinases da Família src/metabolismo
7.
Cell Death Dis ; 4: e504, 2013 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-23429290

RESUMO

Normal cells require adhesion to extracellular matrix for survival. Cell detachment causes a drastic increase in reactive oxygen species (ROS) that promotes anoikis. In the present study, we observed that upon detachment from matrix, human mammary epithelial cells strongly upregulate manganese superoxide dismutase (MnSOD, or SOD2), a principal mitochondrial antioxidant enzyme that detoxifies ROS through dismutation of superoxide. Induction of MnSOD by cell detachment is dependent on the NFκB transcription factor. Detachment of mammary epithelial cells potently increases mitochondrial superoxide levels, which are further elevated by depletion of MnSOD in suspended cells. Consequently, cells depleted of MnSOD are hypersensitive to matrix detachment and exhibit increased anoikis. These results suggest that detachment-induced MnSOD counters mitochondrial superoxide accumulation and confers anoikis resistance. Taken together with our previous finding that detached cells evade excessive ROS production by attenuating oxidative metabolism of glucose, we conclude that mammary epithelial cells coordinate their responses to detachment through increasing MnSOD and decreasing ROS generation from mitochondrial glucose oxidation, thereby mitigating anoikis. Anoikis is a barrier to tumor metastasis. Indeed, MnSOD expression is elevated in human breast cancer metastases compared with primary tumors. Expression of MnSOD correlates with histologic tumor grades in human cancer and contributes to cancer cell's resistance to anoikis. Our study suggests that inhibition of ROS detoxification coupled with stimulation of glucose oxidative metabolism may be an efficient strategy to enhance anoikis and block metastasis.


Assuntos
Anoikis , Superóxido Dismutase/metabolismo , Neoplasias da Mama/enzimologia , Neoplasias da Mama/patologia , Linhagem Celular , Células Epiteliais/citologia , Células Epiteliais/metabolismo , Matriz Extracelular/metabolismo , Feminino , Humanos , Mitocôndrias/metabolismo , NF-kappa B/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/genética , Superóxidos/metabolismo
8.
Oncogene ; 32(17): 2200-10, 2013 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-22689060

RESUMO

Loss of PTEN tumor suppressor enhances metastatic risk in breast cancer, although the underlying mechanisms are poorly defined. We report that homozygous deletion of PTEN in mammary epithelial cells induces tubulin-based microtentacles (McTNs) that facilitate cell reattachment and homotypic aggregation. Treatment with contractility-modulating drugs showed that McTNs in PTEN(-/-) cells are suppressible by controlling the actin cytoskeleton. Because outward microtubule extension is counteracted by actin cortical contraction, increased activity of actin-severing proteins could release constraints on McTN formation in PTEN(-/-) cells. One such actin-severing protein, cofilin, is activated in detached PTEN(-/-) cells that could weaken the actin cortex to promote McTNs. Expression of wild-type cofilin, an activated mutant (S3A), and an inactive mutant (S3E) demonstrated that altering cofilin phosphorylation directly affects McTNs formation. Chemical inhibition of PI3K did not reduce McTNs or inactivate cofilin in PTEN(-/-) cells. Additionally, knock-in expression of the two most common PI3K-activating mutations observed in human cancer patients did not increase McTNs or activate cofilin. PTEN loss and PI3K activation also caused differential activation of the cofilin regulators, LIM-kinase1 (LIMK) and Slingshot-1L (SSH). Furthermore, McTNs were suppressed and cofilin was inactivated by restoration of PTEN in the PTEN(-/-) cells, indicating that both the elevation of McTNs and the activation of cofilin are specific results arising from PTEN loss. These data identify a novel mechanism by which PTEN loss could remodel the cortical actin network to facilitate McTNs that promote tumor cell reattachment and aggregation. Using isogenic MCF-10A PTEN(-/-) and PIK3CA mutants, we have further demonstrated that there are clear differences in activation of cofilin, LIMK and SSH between PTEN loss and PI3K activation, providing a new evidence that these mutations yield distinct cytoskeletal phenotypes, which could have an impact on tumor biology.


Assuntos
Extensões da Superfície Celular/metabolismo , Cofilina 1/metabolismo , Células Epiteliais/metabolismo , PTEN Fosfo-Hidrolase/genética , Fosfatidilinositol 3-Quinases/metabolismo , Actomiosina/metabolismo , Adesão Celular , Linhagem Celular Tumoral , Classe I de Fosfatidilinositol 3-Quinases , Células Epiteliais/ultraestrutura , Técnicas de Inativação de Genes , Humanos , Quinases Lim/metabolismo , Mutação de Sentido Incorreto , PTEN Fosfo-Hidrolase/deficiência , Fosfatidilinositol 3-Quinases/genética , Fosfoproteínas Fosfatases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo
9.
Osteoporos Int ; 22(8): 2283-93, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20941479

RESUMO

UNLABELLED: Diabetic obesity is associated with increased fracture risk in adults and adolescents. We find in both adolescent and adult mice dramatically inferior mechanical properties and structural quality of cortical bone, in agreement with the human fracture data, although some aspects of the response to obesity appear to differ by age. INTRODUCTION: The association of obesity with bone is complex and varies with age. Diabetic obese adolescents and adult humans have increased fracture risk. Prior studies have shown reduced mechanical properties as a result of high-fat diet (HFD) but do not fully address size-independent mechanical properties or structural quality, which are important to understand material behavior. METHODS: Cortical bone from femurs and tibiae from two age groups of C57BL/6 mice fed either HFD or low-fat diet (LFD) were evaluated for structural and bone turnover changes (SEM and histomorphometry) and tested for bending strength, bending stiffness, and fracture toughness. Leptin, IGF-I, and non-enzymatic glycation measurements were also collected. RESULTS: In both young and adult mice fed on HFD, femoral strength, stiffness, and toughness are all dramatically lower than controls. Inferior lamellar and osteocyte alignment also point to reduced structural quality in both age groups. Bone size was largely unaffected by HFD, although there was a shift from increasing bone size in obese adolescents to decreasing in adults. IGF-I levels were lower in young obese mice only. CONCLUSIONS: While the response to obesity of murine cortical bone mass, bone formation, and hormonal changes appear to differ by age, the bone mechanical properties for young and adult groups are similar. In agreement with human fracture trends, adult mice may be similarly susceptible to bone fracture to the young group, although cortical bone in the two age groups responds to diabetic obesity differently.


Assuntos
Envelhecimento , Osso e Ossos/fisiopatologia , Dieta Hiperlipídica/efeitos adversos , Obesidade/fisiopatologia , Envelhecimento/patologia , Envelhecimento/fisiologia , Animais , Fenômenos Biomecânicos , Glicemia/metabolismo , Composição Corporal , Densidade Óssea/fisiologia , Osso e Ossos/patologia , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/patologia , Diabetes Mellitus Experimental/fisiopatologia , Fêmur/fisiopatologia , Fêmur/ultraestrutura , Produtos Finais de Glicação Avançada/sangue , Fator de Crescimento Insulin-Like I/metabolismo , Leptina/sangue , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microscopia Eletrônica de Varredura , Obesidade/sangue , Obesidade/patologia , Fraturas por Osteoporose/etiologia , Fraturas por Osteoporose/patologia , Fraturas por Osteoporose/fisiopatologia , Tíbia/fisiopatologia , Tíbia/ultraestrutura , Aumento de Peso/fisiologia
10.
Oncogene ; 30(13): 1531-41, 2011 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-21102526

RESUMO

The molecular mechanism(s) linking tumorigenesis and morphological alterations in the nucleolus are presently coming into focus. The nucleolus is the cellular organelle in which the formation of ribosomal subunits occurs. Ribosomal biogenesis occurs through the transcription of ribosomal RNA (rRNA), rRNA processing and production of ribosomal proteins. An error in any of these processes may lead to deregulated cellular translation, evident in multiple cancers and 'ribosomopathies'. Deregulated protein synthesis may be achieved through the overexpression of ribosomal proteins as seen in primary leukemic blasts with elevated levels of ribosomal proteins S11 and S14. In this study, we demonstrate that ribosomal protein S6 (RPS6) is highly expressed in primary diffuse large B-cell lymphoma (DLBCL) samples. Genetic modulation of RPS6 protein levels with specifically targeted short hairpin RNA (shRNA) lentiviruses led to a decrease in the actively proliferating population of cells compared with control shRNA. Low-dose rapamycin treatments have been shown to affect the translation of 5' terminal oligopyrimidine (5' TOP) tract mRNA, which encodes the translational machinery, implicating RPS6 in 5' TOP translation. Recently, it was shown that disruption of 40S ribosomal biogenesis through specific small inhibitory RNA knockdown of RPS6 defined RPS6 as a critical regulator of 5' TOP translation. For the first time, we show that RPS6 associates with multiple mRNAs containing a 5' TOP tract. These findings expand our understanding of the mechanism(s) involved in ribosomal biogenesis and deregulated protein synthesis in DLBCL.


Assuntos
Linfoma Difuso de Grandes Células B/metabolismo , Sequência de Oligopirimidina na Região 5' Terminal do RNA/genética , Proteína S6 Ribossômica/fisiologia , Linhagem Celular Tumoral , Nucléolo Celular/fisiologia , Endorribonucleases/análise , Humanos , Fenótipo , Proteínas de Ligação a Poli(A)/análise , Biossíntese de Proteínas , RNA Mensageiro/genética , Proteína S6 Ribossômica/análise , Ribossomos/fisiologia , Sirolimo/farmacologia , Antígeno-1 Intracelular de Células T
11.
Oncogene ; 29(48): 6402-8, 2010 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-20956943

RESUMO

During metastasis, invading cells produce various actin-based membrane protrusions that promote directional migration and proteolysis of extracellular matrix (ECM). Observations of actin staining within thin, tubulin-based microtentacle (McTN) protrusions in suspended MDA-MB-231 tumor cells, prompted an investigation of whether McTNs are structural or functional analogs of invadopodia. We show here that MDA-MB-231 cells are capable of producing invadopodia and McTNs, both of which contain F-actin. Invadopodium formation was enhanced by the expression of a constitutively active c-Src kinase, and repressed by the expression of dominant-negative, catalytically inactive form of c-Src. In contrast, expression of inactive c-Src significantly increased McTN formation. Direct inhibition of c-Src with the SU6656 inhibitor compound also significantly enhanced McTN formation, but suppressed invadopodia, including the appearance of F-actin cores and phospho-cortactin foci, as well as completely blocking focal degradation of ECM. In addition, silencing of Tks5 in Src-transformed fibroblasts blocked invadopodia without affecting McTNs. Genetic modification of c-Src activity that promoted McTN formation augmented capillary retention of circulating tumor cells in vivo and rapid re-attachment of suspended cells in vitro, even though invadopodia were strongly suppressed. These results indicate that McTNs are capable of enhancing tumor cell reattachment, even in the absence of Tks5 and active Src, and define separate cytoskeletal mechanisms and functions for McTNs and invadopodia.


Assuntos
Actinas/metabolismo , Neoplasias da Mama/metabolismo , Extensões da Superfície Celular/fisiologia , Citoesqueleto/fisiologia , Matriz Extracelular/metabolismo , Proteínas Tirosina Quinases/fisiologia , Proteínas Proto-Oncogênicas/fisiologia , Células 3T3 , Animais , Proteína Tirosina Quinase CSK , Linhagem Celular Tumoral , Feminino , Humanos , Camundongos , Microtúbulos/fisiologia , Quinases da Família src
12.
Oncogene ; 29(22): 3217-27, 2010 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-20228842

RESUMO

The cytoskeletal organization of detached and circulating tumor cells (CTCs) is currently not well defined and may provide potential targets for new therapies to limit metastatic tumor spread. In vivo, CTCs reattach in distant tissues by a mechanism that is tubulin-dependent and suppressed by polymerized actin. The cytoskeletal mechanisms that promote reattachment of CTCs match exactly with the mechanisms supporting tubulin microtentacles (McTN), which we have recently identified in detached breast tumor cells. In this study, we aimed to investigate how McTN formation is affected by the microtubule-associated protein, tau, which is expressed in a subset of chemotherapy-resistant breast cancers. We demonstrate that endogenous tau protein localizes to McTNs and is both necessary and sufficient to promote McTN extension in detached breast tumor cells. Tau-induced McTNs increase reattachment of suspended cells and retention of CTCs in lung capillaries. Analysis of patient-matched primary and metastatic tumors reveals that 52% possess tau expression in metastases and 26% display significantly increased tau expression over disease progression. Tau enrichment in metastatic tumors and the ability of tau to promote tumor cell reattachment through McTN formation support a model in which tau-induced microtubule stabilization provides a selective advantage during tumor metastasis.


Assuntos
Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Tubulina (Proteína)/metabolismo , Proteínas tau/biossíntese , Neoplasias da Mama/irrigação sanguínea , Neoplasias da Mama/tratamento farmacológico , Adesão Celular , Linhagem Celular Tumoral , Citoesqueleto/metabolismo , Feminino , Técnicas de Silenciamento de Genes , Humanos , Invasividade Neoplásica , Metástase Neoplásica , Células Tumorais Cultivadas , Proteínas tau/genética
13.
Bone ; 46(1): 217-25, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19853069

RESUMO

Overweight and obesity are rapidly expanding health problems in children and adolescents. Obesity is associated with greater bone mineral content that might be expected to protect against fracture, which has been observed in adults. Paradoxically, however, the incidence of bone fractures has been found to increase in overweight and obese children and adolescents. Prior studies have shown some reduced mechanical properties as a result of high-fat diet (HFD) but do not fully address size-independent measures of mechanical properties, which are important to understand material behavior. To clarify the effects of HFD on the mechanical properties and microstructure of bone, femora from C57BL/6 mice fed either a HFD or standard laboratory chow (Chow) were evaluated for structural changes and tested for bending strength, bending stiffness and fracture toughness. Here, we find that in young, obese, high-fat fed mice, all geometric parameters of the femoral bone, except length, are increased, but strength, bending stiffness, and fracture toughness are all reduced. This increased bone size and reduced size-independent mechanical properties suggests that obesity leads to a general reduction in bone quality despite an increase in bone quantity; yield and maximum loads, however, remained unchanged, suggesting compensatory mechanisms. We conclude that diet-induced obesity increases bone size and reduces size-independent mechanical properties of cortical bone in mice. This study indicates that bone quantity and bone quality play important compensatory roles in determining fracture risk.


Assuntos
Osso e Ossos/patologia , Dieta , Gorduras na Dieta/efeitos adversos , Obesidade/induzido quimicamente , Obesidade/patologia , Animais , Fenômenos Biomecânicos , Composição Corporal , Densidade Óssea , Osso e Ossos/metabolismo , Osso e Ossos/fisiopatologia , Modelos Animais de Doenças , Teste de Tolerância a Glucose , Fator de Crescimento Insulin-Like I/metabolismo , Leptina/sangue , Masculino , Camundongos , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Obesidade/metabolismo , Tomografia Computadorizada por Raios X
14.
Oncogene ; 28(10): 1339-47, 2009 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-19151760

RESUMO

GRIM-19 (Gene associated with Retinoid-Interferon-induced Mortality 19) is a novel tumor suppressor regulated by interferon/retinoid combination. We have recently shown that GRIM-19 inhibits v-Src-induced oncogenic transformation and metastatic behavior of cells. Oncogenic v-Src induces cell motility by cytoskeletal remodeling, especially the formation of podosomes and. Here, we show that GRIM-19 inhibited the v-Src-induced cell motility by inhibiting cytoskeletal remodeling, that is, podosome formation. We also show that the N terminus of GRIM-19 played a major role in this process and identified critical residues in this region. More importantly, we show that tumor-associated GRIM-19 mutations disrupted its ability to inhibit v-Src-induced cell motility. These actions appear to occur independently of STAT3, a known target of GRIM-19-mediated inhibition. Lastly, tumor-associated GRIM-19 mutants significantly lost their ability to control v-Src-induced metastases in vivo, indicating the biological and pathological significance of these observations.


Assuntos
Movimento Celular , Citoesqueleto/química , NADH NADPH Oxirredutases/fisiologia , Proteína Oncogênica pp60(v-src)/antagonistas & inibidores , Animais , Transformação Celular Neoplásica , Cortactina/metabolismo , Camundongos , NADH NADPH Oxirredutases/química , NADH NADPH Oxirredutases/genética , Fosforilação , Relação Estrutura-Atividade
15.
AIDS Care ; 17 Suppl 1: S77-87, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16096120

RESUMO

Brazil has the second largest number of reported AIDS cases in the world. Porto Alegre, like most other large urban centres in Brazil, has been greatly impacted by an AIDS epidemic driven by high rates of drug use and risky sexual behaviours. While epidemiologic surveillance of HIV/AIDS and treatment initiatives for HIV-infected individuals are well developed in Brazil, comparatively little attention has focused on developing interventions directed toward high-risk populations. Intervention programmes, particularly those tailored for chronic drug users, are lacking. This pilot project successfully adapted and tailored a cognitive behavioural HIV intervention developed in the US to the cultural setting in Porto Alegre. The project established feasibility and acceptability of the approach for targeting risky drug and sexual behaviours among a group of male Brazilian drug users. A sample of 120 male cocaine users was recruited from a public health clinic serving the target population in the city of Porto Alegre. The average age of the participants was 29; they averaged less than 8 years of formal education; and less than half (41%) were married. Lifetime self-reported drug use was high with 93% reporting cocaine use, 87% reporting crack use, and 100% reporting marijuana use. 43% of the sample reported ever injecting drugs. Reports of risky sexual behaviours were similarly elevated. Almost half (45%) tested positive for HIV. Preliminary evidence suggests that intervention acceptability was high among participants. Given the reported high risk sexual and drug use behaviours among these men, HIV interventions must be evaluated and expanded to include this population as well as their sexual partners.


Assuntos
Terapia Cognitivo-Comportamental/métodos , Transtornos Relacionados ao Uso de Substâncias/terapia , Adolescente , Adulto , Brasil , Transtornos Relacionados ao Uso de Cocaína/complicações , Transtornos Relacionados ao Uso de Cocaína/terapia , Humanos , Masculino , Aceitação pelo Paciente de Cuidados de Saúde , Projetos Piloto , Assunção de Riscos , Abuso de Substâncias por Via Intravenosa/complicações , Abuso de Substâncias por Via Intravenosa/terapia , Transtornos Relacionados ao Uso de Substâncias/complicações
16.
J Mol Biol ; 313(1): 49-69, 2001 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-11601846

RESUMO

The crystal structure of a novel Cre-Lox synapse was solved using phases from multiple isomorphous replacement and anomalous scattering, and refined to 2.05 A resolution. In this complex, a symmetric protein trimer is bound to a Y-shaped three-way DNA junction, a marked departure from the pseudo-4-fold symmetrical tetramer associated with Cre-mediated LoxP recombination. The three-way DNA junction was accommodated by a simple kink without significant distortion of the adjoining DNA duplexes. Although the mean angle between DNA arms in the Y and X structures was similar, adjacent Cre trimer subunits rotated 29 degrees relative to those in the tetramers. This rotation was accommodated at the protein-protein and DNA-DNA interfaces by interactions that are "quasi-equivalent" to those in the tetramer, analogous to packing differences of chemically identical viral subunits at non-equivalent positions in icosahedral capsids. This structural quasi-equivalence extends to function as Cre can bind to, cleave and perform strand transfer with a three-way Lox substrate. The structure explains the dual recognition of three and four-way junctions by site-specific recombinases as being due to shared structural features between the differently branched substrates and plasticity of the protein-protein interfaces. To our knowledge, this is the first direct demonstration of quasi-equivalence in both the assembly and function of an oligomeric enzyme.


Assuntos
Sítios de Ligação Microbiológicos/genética , DNA Bacteriano/química , DNA Bacteriano/metabolismo , Integrases/química , Integrases/metabolismo , Conformação de Ácido Nucleico , Recombinação Genética , Proteínas Virais/química , Proteínas Virais/metabolismo , Sequência de Bases , Sítios de Ligação , Catálise , Cristalografia por Raios X , DNA Bacteriano/genética , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/metabolismo , Modelos Moleculares , Ligação Proteica , Estrutura Quaternária de Proteína , Subunidades Proteicas , Rotação , Relação Estrutura-Atividade
17.
Adolescence ; 36(142): 289-304, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11572307

RESUMO

The subjects for the present study were drawn from the female students who participated in the National Education Longitudinal Study (NELS) initial eighth-grade data collection. Adolescent females who later became pregnant were matched on race, birth month, and birth year with adolescent females who did not report a pregnancy. The study examined selected predictor variables from the baseline 1988 wave of data in relation to the outcome variable of pregnancy status. Results indicated a statistically significant difference in locus of control between those females who later became pregnant and those who later did not experience a pregnancy during adolescence. Those who later became pregnant were much more likely to have an external locus of control (p = .0001). Females who later became pregnant were also more likely to have a poorer sense of personal efficacy (p = .0001). Finally, females who later experienced a teen pregnancy had more traditional occupational expectations (p = .006) and lower educational expectations (p = .001) than did those who did not later report a teen pregnancy.


Assuntos
Controle Interno-Externo , Desenvolvimento da Personalidade , Gravidez na Adolescência/psicologia , Adolescente , Aspirações Psicológicas , Feminino , Humanos , Recém-Nascido , Estudos Longitudinais , Gravidez , Fatores de Risco , Autoeficácia , Estados Unidos
18.
Mol Cell Biol ; 21(19): 6529-36, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11533241

RESUMO

Many tumor cells are impaired in adhesion-regulated apoptosis, which contributes to their metastatic potential. However, suppression of this apoptotic pathway in untransformed cells is not mediated only by adhesion to the extracellular matrix but also through the resulting ability to spread and adopt a distinct morphology. Since cell spreading is dependent on the integrity of the actin microfilament cytoskeleton, we sought to determine if actin depolymerization was sufficient to induce apoptosis, even in the presence of continuous attachment. For this study, we used a human mammary epithelial cell line (MCF10A), which is immortalized but remains adhesion dependent for survival. Treatment of MCF10A cells with latrunculin-A (LA), an inhibitor of actin polymerization, rapidly led to disruption of the actin cytoskeleton and caused cell rounding but preserved attachment. Initiation of apoptosis in LA-treated MCF10A cells was detected by mitochondrial localization of the Bax apoptotic protein, which was prevented by overexpression of Bcl-2. DNA fragmentation and poly(ADP-ribose) polymerase (PARP) cleavage in LA-treated MCF10A cells indicated progression to the execution phase of apoptosis. The MDA-MB-453 cell line, which was derived from a metastatic human mammary tumor, was resistant to PARP cleavage and loss of viability in response to actin depolymerization. Stable overexpression of Bcl-2 in the untransformed MCF10A cells was able to recapitulate the resistance to apoptosis found in the tumor cell line. We demonstrate that inhibition of actin polymerization is sufficient to stimulate apoptosis in attached MCF10A cells, and we present a novel role for Bcl-2 in cell death induced by direct disruption of the actin cytoskeleton.


Assuntos
Actinas/metabolismo , Apoptose , Neoplasias da Mama/patologia , Mama/citologia , Proteínas Proto-Oncogênicas c-bcl-2/fisiologia , Neoplasias da Mama/metabolismo , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Adesão Celular , Linhagem Celular Transformada , Sobrevivência Celular , Células Epiteliais/citologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Feminino , Humanos , Mitocôndrias/metabolismo , Metástase Neoplásica , Poli(ADP-Ribose) Polimerase-1 , Poli(ADP-Ribose) Polimerases , Transporte Proteico , Proteínas/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/genética , Tiazóis/farmacologia , Tiazolidinas , Transfecção , Células Tumorais Cultivadas , Proteína X Associada a bcl-2
19.
Am J Sports Med ; 29(3): 288-91, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11394596

RESUMO

Cryotherapy is a modality commonly used after arthroscopic procedures. We divided 17 patients into two groups after routine knee arthroscopy: 12 patients were immediately treated with ice and 5 control patients were treated without ice for the first hour. In all patients, thermocouple probes were placed intraarticularly into the lateral gutter of the knee. Ice was placed on the operative knees of the treatment group for 2 hours. The control group had no intervention for the 1st hour and then had ice applied for the 2nd hour. Temperatures were continually recorded every minute for 2 hours. The temperature in the treatment group declined significantly, by 2.2 degrees C (95% confidence interval [-3.6 degrees C, -0.72 degrees C]) over the 1st hour and by 0.79 degrees C (95% CI [-1.8 degrees C, 0.18 degrees C]) over the 2nd hour (P = 0.008). The temperature in the control group increased significantly, by 5.0 degrees C (95% CI [2.4 degrees C, 7.5 degrees C]) over the 1st hour (P = 0.006). After ice was applied, the temperature fell significantly, by 4.0 degrees C (95% CI [-8.3 degrees C, 0.26 degrees C]) (P = 0.06). The difference between the temperature decrease in the treatment group and the increase in the control group at 60 minutes was 7.1 degrees C. This is the first rigorously conducted study in human patients that documents a statistically significant decline in intraarticular knee temperature with the application of ice and compression to the skin. The mechanism by which cryotherapy acts must therefore include the cooling effect on the intraarticular environment and synovium.


Assuntos
Artroscopia , Temperatura Corporal , Crioterapia , Joelho/fisiopatologia , Joelho/cirurgia , Cuidados Pós-Operatórios , Adulto , Idoso , Artroscopia/efeitos adversos , Crioterapia/instrumentação , Crioterapia/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/prevenção & controle , Estudos Prospectivos
20.
Drug Alcohol Depend ; 62(3): 195-203, 2001 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-11295324

RESUMO

This cross-sectional school-based study explored the relationship between adolescent use of cigarettes and marijuana and the sensation seeking personality factors of (1) Disinhibition and (2) Thrill and Adventure Seeking. The study population included a representative sample of both male and female 8th and 11th graders in the state of Delaware. Analytic methods utilized included correlational analysis and multivariate logistic regression. In the multivariate logistic regression models, the Disinhibition personality factor accounted for cigarette and marijuana using behaviors with odds ratios ranging between 2 and 3. Thrill and Adventure Seeking was not a significant explanatory variable in any of the final multivariate models. Potential confounders (age, gender and race) were considered in all analyses. Of all the two-way interactions assessed, none was significant. The findings from this study utilizing a large general community sample indicate that sensation seeking needs are a potential risk factor for adolescent substance use.


Assuntos
Comportamento Exploratório , Fumar Maconha/psicologia , Assunção de Riscos , Fumar/psicologia , Estudantes/psicologia , Adolescente , Intervalos de Confiança , Estudos Transversais , Feminino , Humanos , Modelos Logísticos , Masculino , Análise Multivariada , Razão de Chances
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...