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1.
Pathologe ; 38(Suppl 2): 198-201, 2017 Nov.
Artigo em Alemão | MEDLINE | ID: mdl-28849372

RESUMO

Ewing sarcoma is a highly aggressive bone or soft-tissue tumor mostly occurring in children and adolescents. Conventional multi-modal therapies are associated with considerable acute and chronic toxicity. Thus, more effective and in particular less toxic therapeutic strategies are urgently required. Despite the fact that Ewing sarcoma is characterized by specific EWSR1-ETS gene fusions, the resulting fusion oncoproteins are not suitable for targeted therapy due to their low immunogenicity and the ubiquitous expression of their constituents. However, functional genomics revealed several EWSR1-ETS target genes, which are only minimally expressed in normal tissues, and which could serve as surrogate-targets for (immuno-)therapeutic approaches. Moreover, functional genomic analyses yielded first mechanistic explanations for the relatively high incidence of Ewing sarcoma in Europeans, and first studies are exploring the value of circulating free DNA and/or exosomal mRNA of EWSR1-ETS fusion oncogenes as minimal-residual-disease markers in Ewing sarcoma. This review summarizes key contributions to these aspects and gives a perspective on their medical relevance.


Assuntos
Neoplasias Ósseas/genética , Sarcoma de Ewing/genética , Adolescente , Neoplasias Ósseas/terapia , Criança , Genômica , Humanos , Proteínas de Fusão Oncogênica/metabolismo , Proteína EWS de Ligação a RNA/metabolismo , Sarcoma de Ewing/terapia
2.
Pathologe ; 37(3): 269-74, 2016 May.
Artigo em Alemão | MEDLINE | ID: mdl-26919849

RESUMO

Q fever is a worldwide distributed zoonotic disease with a mostly benign course, which regularly reoccurs in Germany. This report is about a patient with sporadic serologically proven Q fever, which also showed typical histopathological findings with nonspecific granulomatous hepatitis, usually seen in acute disease. The bone marrow biopsy revealed so-called doughnut granulomas, which are not pathognomonic but a typical finding in Q fever. This case report impressively underlines that the histomorphological findings can make a decisive contribution to the clarification by extended differential diagnostics, even though it plays a subordinate role in the routine diagnostics of disseminated Q fever.


Assuntos
Doença Granulomatosa Crônica/diagnóstico , Doença Granulomatosa Crônica/patologia , Hepatite A/diagnóstico , Hepatite A/patologia , Febre Q/diagnóstico , Febre Q/patologia , Doenças Raras , Adulto , Antibacterianos/uso terapêutico , Valva Aórtica/patologia , Biópsia por Agulha , Medula Óssea/patologia , Diagnóstico Diferencial , Quimioterapia Combinada , Endocardite Bacteriana/diagnóstico , Endocardite Bacteriana/tratamento farmacológico , Endocardite Bacteriana/patologia , Doença Granulomatosa Crônica/tratamento farmacológico , Hepatite A/tratamento farmacológico , Humanos , Fígado/patologia , Masculino , Febre Q/tratamento farmacológico , Recidiva
3.
Br J Cancer ; 109(10): 2523-32, 2013 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-24149176

RESUMO

BACKGROUND: Allogeneic haematopoietic stem cell transplantation (allo-SCT) may provide donor cytotoxic T cell-/NK cell-mediated disease control in patients with rhabdomyosarcoma (RMS). However, little is known about the prevalence of graft-vs-RMS effects and only a few case experiences have been reported. METHODS: We evaluated allo-SCT outcomes of 30 European Group for Blood and Marrow Transplantation (EBMT)-registered patients with advanced RMS regarding toxicity, progression-free survival (PFS) and overall survival (OS) after allo-SCT. Twenty patients were conditioned with reduced intensity and ten with high-dose chemotherapy. Twenty-three patients were transplanted with HLA-matched and seven with HLA-mismatched grafts. Three patients additionally received donor lymphocyte infusions (DLIs). Median follow-up was 9 months. RESULTS: Three-year OS was 20% (s.e.±8%) with a median survival time of 12 months. Cumulative risk of progression was 67% (s.e.±10%) and 11% (s.e.±6%) for death of complications. Thirteen patients developed acute graft-vs-host disease (GvHD) and five developed chronic GvHD. Eighteen patients died of disease and four of complications. Eight patients survived in complete remission (CR) (median: 44 months). No patients with residual disease before allo-SCT were converted to CR. CONCLUSION: The use of allo-SCT in patients with advanced RMS is currently experimental. In a subset of patients, it may constitute a valuable approach for consolidating CR, but this needs to be validated in prospective trials.


Assuntos
Transplante de Células-Tronco Hematopoéticas/métodos , Rabdomiossarcoma/cirurgia , Adolescente , Adulto , Criança , Pré-Escolar , Progressão da Doença , Feminino , Doença Enxerto-Hospedeiro/etiologia , Doença Enxerto-Hospedeiro/mortalidade , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Humanos , Masculino , Recidiva Local de Neoplasia/epidemiologia , Recidiva Local de Neoplasia/mortalidade , Estudos Retrospectivos , Rabdomiossarcoma/mortalidade , Transplante Homólogo , Adulto Jovem
4.
Ann Oncol ; 23(8): 2185-2190, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22317770

RESUMO

BACKGROUND: Ewing's sarcoma (ES) is the second most common bone or soft-tissue sarcoma in childhood and adolescence and features a high propensity to metastasize. The six-transmembrane epithelial antigen of the prostate 1 (STEAP1) is a membrane-bound mesenchymal stem cell marker highly expressed in ES. Here, we investigated the role of STEAP1 as an immunohistological marker for outcome prediction in patients with ES. PATIENTS AND METHODS: Membranous STEAP1 immunoreactivity was analyzed using immunohistochemistry in 114 primary pre-chemotherapy ES of patients diagnosed from 1983 to 2010 and compared with clinical parameters and patient outcome. Median follow-up was 3.85 years (range 0.43-17.51). RESULTS: A total of 62.3% of the ES samples displayed detectable STEAP1 expression with predominant localization of the protein at the plasma membrane. High membranous STEAP1 immunoreactivity was found in 53.5%, which correlated with better overall survival (P=0.021). Accordingly, no or low membranous STEAP1 expression was identified as an independent risk factor in multivariate analysis (hazard ratio 2.65, P=0.036). CONCLUSION: High membranous STEAP1 expression predicts improved outcome and may help to define a specific subgroup of ES patients, who might benefit from adapted therapy regimens.


Assuntos
Antígenos de Neoplasias/biossíntese , Oxirredutases/biossíntese , Sarcoma de Ewing/imunologia , Adolescente , Adulto , Biomarcadores Tumorais/biossíntese , Membrana Celular/enzimologia , Membrana Celular/imunologia , Criança , Pré-Escolar , Feminino , Humanos , Imuno-Histoquímica , Lactente , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Sarcoma de Ewing/enzimologia , Adulto Jovem
5.
Klin Padiatr ; 224(3): 124-31, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22522984

RESUMO

Although prognosis of children with solid tumors is steadily improving, long-term survival is not achievable in all patients, especially in patients with recurrent or refractory disease. Despite the increasing number of targeted therapeutics (TT), only very few TT have been introduced into clinical protocols. Accordingly, clinical experience concerning the efficacy and safety of these drugs is limited. This may possibly discourage oncologists from administering TT to children.We performed a comprehensive review of the literature to identify TT that may be considered for treatment of children and young adults with solid tumors. Moreover, we interviewed an expert panel of the Society for Pediatric Oncology and Hematology (GPOH) using questionnaires in a modified Delphi process in order to describe the experts' experiences in the use of these TT.Among 30 TT identified to be possibly useful in children and young adults, imatinib, bevacizumab and rapamycin were most widely used. These drugs were reported as having mostly little to no severe adverse events and seem to induce at least partial responses in a subset of patients. In addition, our study confirms and expands the present knowledge about adverse events and the potential efficacy of 5 other commonly used TT in this population.This information may be useful for oncologists when administering these TT to children and young adults with solid tumors. Controlled clinical trials are urgently needed to test their safety and efficacy.


Assuntos
Terapia de Alvo Molecular , Neoplasias/tratamento farmacológico , Adolescente , Anticorpos Monoclonais Humanizados/uso terapêutico , Anticorpos Monoclonais Humanizados/toxicidade , Benzamidas , Bevacizumab , Criança , Técnica Delphi , Humanos , Mesilato de Imatinib , Piperazinas/uso terapêutico , Piperazinas/toxicidade , Pirimidinas/uso terapêutico , Pirimidinas/toxicidade , Sirolimo/uso terapêutico , Sirolimo/toxicidade , Adulto Jovem
6.
Klin Padiatr ; 224(6): 353-8, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22821288

RESUMO

BACKGROUND: Risk stratification criteria for patients with Ewing's sarcoma family of tumors (ESFT) are still limited. We hypothesized divergent human leukocyte antigen (HLA) patterns in ESFT patients and compared HLA-A, -B and -DR phenotype frequencies of patients with advanced ESFT with those of healthy controls. PATIENTS: HLA types of all German Caucasian patients with advanced ESFT and available HLA-A, -B and -DR data registered in the European Group for Blood and Marrow Transplantation, Paediatric Registry for Stem Cell Transplantation and the MetaEICESS data bases (study group, n=30) were retrospectively compared with HLA types of healthy German stem cell donors (control group, n=8 862 for single HLA frequencies and n=8 839 for allele combinations). Study group patients had been immuno-typed due to eligibility for allogeneic stem cell transplantation for high risk of treatment failure, and thus constituted a selected subgroup of ESFT patients. RESULTS: After Bonferroni correction for multiple testing (PC), phenotype frequencies of HLA-A24 remained significantly higher in the study group compared to controls (PC<0.05). Furthermore, several HLA combinations were significantly more frequent in the study group compared to controls (all PC<0.05). CONCLUSION: We report an increased incidence of circumscribed HLA patterns in German Caucasians with advanced ESFT. The possible clinical significance of this observation has to be re-assessed in prospective trials comprising larger ESFT patient numbers of all risk groups.


Assuntos
Doadores de Sangue , Transplante de Medula Óssea , Neoplasias Ósseas/genética , Neoplasias Ósseas/terapia , Antígenos HLA-A/genética , Antígenos HLA-B/genética , Antígenos HLA-DR/genética , Transplante de Células-Tronco Hematopoéticas , Sarcoma de Ewing/genética , Sarcoma de Ewing/terapia , Doadores de Tecidos , Adolescente , Adulto , Neoplasias Ósseas/patologia , Criança , Progressão da Doença , Feminino , Frequência do Gene , Genética Populacional , Alemanha , Humanos , Masculino , Recidiva Local de Neoplasia/genética , Recidiva Local de Neoplasia/patologia , Recidiva Local de Neoplasia/terapia , Estadiamento de Neoplasias , Estudos Retrospectivos , Sarcoma de Ewing/patologia , Adulto Jovem
8.
Unfallchirurg ; 115(6): 503-10, 2012 Jun.
Artigo em Alemão | MEDLINE | ID: mdl-22639059

RESUMO

The burden of musculoskeletal infections is permanently growing. A probable explanation for this development could be the increasing number of elderly people undergoing extensive surgery using implants and prosthetic devices while having more significant comorbidities (e.g. cardiovascular, metabolic and malignant). However, a relative reduction of acute (hematogenous) osteomyelitis compared to the occurrence of much more complex situations, such as diabetic foot syndrome or chronic osteitis and prosthetic implant infections is being observed. This poses new challenges for the clinician in managing these patients. Furthermore, there is the evolving threat of antimicrobial resistance as well as the increasing amount of infections with Gram-negative pathogens. Several aspects have to be considered for successful management of musculoskeletal infections: the site of infection and feasibility of local surgical treatment, the effectiveness of antimicrobial treatment, the inclusion of comorbidities and their specific treatment in an advanced therapeutic concept as well as the interdisciplinary approach led by surgeons and infectious disease specialists.


Assuntos
Antibacterianos/uso terapêutico , Artrite Infecciosa/diagnóstico , Artrite Infecciosa/terapia , Artroplastia/métodos , Desbridamento/métodos , Resistência Microbiana a Medicamentos , Terapia Combinada , Humanos , Falha de Tratamento
9.
Eur J Clin Microbiol Infect Dis ; 30(12): 1557-60, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21516515

RESUMO

The risk of cytomegalovirus (CMV) reactivation among hemodialysis (HD) patients is unknown. In 52 HD patients from a single center, CMV serology and quantitative PCR were performed. The detection limit of PCR was 20 copies/ml. Here, PCR ruled out CMV viremia, despite CMV-IgM seropositivity in 15.4% patients.


Assuntos
Infecções por Citomegalovirus/epidemiologia , Infecções por Citomegalovirus/virologia , Citomegalovirus/isolamento & purificação , Diálise Renal/efeitos adversos , Diálise Renal/métodos , Ativação Viral , Citomegalovirus/genética , Citomegalovirus/imunologia , Humanos , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Testes Sorológicos , Viremia/diagnóstico
10.
Br J Cancer ; 102(11): 1645-53, 2010 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-20461080

RESUMO

BACKGROUND: LIM and SH3 protein 1 (LASP-1) is a nucleo-cytoplasmatic signalling protein involved in cell proliferation and migration and is upregulated in breast cancer in vitro studies have shown that LASP-1 might be regulated by prostate-derived ETS factor (PDEF), p53 and/or LASP1 gene amplification. This current study analysed the prognostic significance of LASP-1 on overall survival (OS) in 177 breast cancer patients and addressed the suggested mechanisms of LASP-1-regulation. METHODS: Nucleo-cytoplasmatic LASP-1-positivity of breast carcinoma samples was correlated with long-term survival, clinicopathological parameters, Ki67-positivity and PDEF expression. Rate of LASP1 amplification was determined in micro-dissected primary breast cancer cells using quantitative RT-PCR. Cell-phase dependency of nuclear LASP-1-localisation was studied in synchronised cells. In addition, LASP-1, PDEF and p53 expression was compared in cell lines of different tumour entities to define principles for LASP-1-regulation. RESULTS: We showed that LASP-1 overexpression is not due to LASP1 gene amplification. Moreover, no correlation between p53-mutations or PDEF-expression and LASP-1-status was observed. However, nuclear LASP-1-localisation in breast carcinomas is increased during proliferation with peak in G2/M-phase and correlated significantly with Ki67-positivity and poor OS. CONCLUSION: Our results provide evidence that nuclear LASP-1-positivity may serve as a negative prognostic indicator for long-term survival of breast cancer patients.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Neoplasias da Mama/mortalidade , Carcinoma/mortalidade , Núcleo Celular/metabolismo , Proteínas do Citoesqueleto/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Carcinoma/diagnóstico , Carcinoma/genética , Carcinoma/metabolismo , Linhagem Celular Tumoral , Proteínas do Citoesqueleto/genética , Feminino , Amplificação de Genes/fisiologia , Humanos , Proteínas com Domínio LIM , Pessoa de Meia-Idade , Prognóstico , Análise de Sobrevida , Sobreviventes/estatística & dados numéricos , Fatores de Tempo , Distribuição Tecidual
11.
Artigo em Alemão | MEDLINE | ID: mdl-19214459

RESUMO

The introduction of tropical diseases into Germany is becoming a more and more frequent public health problem due to increasing long distance travel and the globalization of economic activities. A network of centers of excellence for imported, highly contagious diseases has proven efficient and shown that the linking of public health service, clinical care, laboratory-based special diagnostics, ambulance service, and hospital hygiene can react quickly and professionally in even unexpected situations in clinical infectiology. These networks joined forces in the "Permanent Working Group of the Medical Competence and Treatment Centers" (Ständigen Arbeitsgemeinschaft der Kompetenz- und Behandlungszentren, StAKoB). Not only in Germany but also worldwide, the StAKoB is a unique system for the treatment of imported highly contagious diseases. The goals and structure of the StAKoB are presented in this article.


Assuntos
Controle de Doenças Transmissíveis/organização & administração , Doenças Transmissíveis Emergentes/prevenção & controle , Serviços Médicos de Emergência/organização & administração , Saúde Global , Objetivos Organizacionais , Competência Profissional/normas , Medicina Tropical/organização & administração , Controle de Doenças Transmissíveis/normas , Doenças Transmissíveis Emergentes/epidemiologia , Serviços Médicos de Emergência/normas , Alemanha , Humanos , Prática de Saúde Pública/normas , Viagem
12.
Eur J Cancer ; 109: 137-153, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30721788

RESUMO

INTRODUCTION: Treatment of patients with metastatic melanoma is hampered by drug-resistance and often requires combination with radiotherapy as last-resort option. However, also after radiotherapy, clinical relapses are common. METHODS & RESULTS: Our preclinical models indicated a higher rate of tumour relapse when melanoma cells were first treated with BRAFV600E inhibition (BRAFi) followed by radiotherapy as compared to the reverse sequence. Accordingly, retrospective follow-up data from 65 stage-IV melanoma patients with irradiated melanoma brain metastases confirmed a shortened duration of local response of mitogen-activated protein kinase (MAPK)-inhibitor-pretreated compared with MAPK-inhibitor-naïve intracranial metastases. On the molecular level, we identified JARID1B/KDM5B as a cellular marker for cross-resistance between BRAFi and radiotherapy. JARID1Bhigh cells appeared more frequently under upfront BRAFi as compared with upfront radiation. JARID1B favours cell survival by transcriptional regulation of genes controlling cell cycle, DNA repair and cell death. CONCLUSION: The level of cross-resistance between combined MAPK inhibition and radiotherapy is dependent on the treatment sequence. JARID1B may represent a novel therapy-overarching resistance marker.


Assuntos
Neoplasias Encefálicas/terapia , Resistencia a Medicamentos Antineoplásicos , Melanoma/terapia , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Tolerância a Radiação , Radioterapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Apoptose , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/secundário , Ciclo Celular , Movimento Celular , Proliferação de Células , Quimiorradioterapia , Feminino , Seguimentos , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Melanoma/genética , Melanoma/patologia , Pessoa de Meia-Idade , Mutação , Prognóstico , Proteínas Proto-Oncogênicas B-raf/genética , Estudos Retrospectivos , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
13.
Chem Mater ; 29(10): 4511-4522, 2017 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-28572705

RESUMO

The synthesis of iron oxide nanoparticles (NPs) by thermal decomposition of iron precursors using oleic acid as surfactant has evolved to a state-of-the-art method to produce monodisperse, spherical NPs. The principles behind such monodisperse syntheses are well-known: the key is a separation between burst nucleation and growth phase, whereas the size of the population is set by the precursor-to-surfactant ratio. Here we follow the thermal decomposition of iron pentacarbonyl in the presence of oleic acid via in situ X-ray scattering. This method allows reaction kinetics and precursor states to be followed with high time resolution and statistical significance. Our investigation demonstrates that the final particle size is directly related to a phase of inorganic cluster formation that takes place between precursor decomposition and particle nucleation. The size and concentration of clusters were shown to be dependent on precursor-to-surfactant ratio and heating rate, which in turn led to differences in the onset of nucleation and concentration of nuclei after the burst nucleation phase. This first direct observation of prenucleation formation of inorganic and micellar structures in iron oxide nanoparticle synthesis by thermal decomposition likely has implications for synthesis of other NPs by similar routes.

14.
Oncogene ; 36(6): 766-776, 2017 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-27375017

RESUMO

Ewing sarcoma is characterized by chromosomal translocations fusing the EWS gene with various members of the ETS family of transcription factors, most commonly FLI1. EWS-FLI1 is an aberrant transcription factor driving Ewing sarcoma tumorigenesis by either transcriptionally inducing or repressing specific target genes. Herein, we showed that Sprouty 1 (SPRY1), which is a physiological negative feedback inhibitor downstream of fibroblast growth factor (FGF) receptors (FGFRs) and other RAS-activating receptors, is an EWS-FLI1 repressed gene. EWS-FLI1 knockdown specifically increased the expression of SPRY1, while other Sprouty family members remained unaffected. Analysis of SPRY1 expression in a panel of Ewing sarcoma cells showed that SPRY1 was not expressed in Ewing sarcoma cell lines, suggesting that it could act as a tumor suppressor gene in these cells. In agreement, induction of SPRY1 in three different Ewing sarcoma cell lines functionally impaired proliferation, clonogenic growth and migration. In addition, SPRY1 expression inhibited extracellular signal-related kinase/mitogen-activated protein kinase (MAPK) signaling induced by serum and basic FGF (bFGF). Moreover, treatment of Ewing sarcoma cells with the potent FGFR inhibitor PD-173074 reduced bFGF-induced proliferation, colony formation and in vivo tumor growth in a dose-dependent manner, thus mimicking SPRY1 activity in Ewing sarcoma cells. Although the expression of SPRY1 was low when compared with other tumors, SPRY1 was variably expressed in primary Ewing sarcoma tumors and higher expression levels were significantly associated with improved outcome in a large patient cohort. Taken together, our data indicate that EWS-FLI1-mediated repression of SPRY1 leads to unrestrained bFGF-induced cell proliferation, suggesting that targeting the FGFR/MAPK pathway can constitute a promising therapeutic approach for this devastating disease.


Assuntos
Proteínas de Membrana/metabolismo , Proteínas de Fusão Oncogênica/metabolismo , Fosfoproteínas/metabolismo , Proteína Proto-Oncogênica c-fli-1/metabolismo , Proteína EWS de Ligação a RNA/metabolismo , Sarcoma de Ewing/metabolismo , Sarcoma de Ewing/patologia , Proteínas ras/antagonistas & inibidores , Animais , Linhagem Celular Tumoral , Feminino , Xenoenxertos , Humanos , Sistema de Sinalização das MAP Quinases , Masculino , Camundongos , Camundongos SCID , Transdução de Sinais , Proteínas ras/metabolismo
16.
Biomaterials ; 76: 250-60, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26546917

RESUMO

Biocompatibility is a key issue in the development of new implant materials. In this context, a novel class of biodegrading Mg implants exhibits promising properties with regard to inflammatory response and mechanical properties. The interaction between Mg degradation products and the nanoscale structure and mineralization of bone, however, is not yet sufficiently understood. Investigations by synchrotron microbeam x-ray fluorescence (µXRF), small angle x-ray scattering (µSAXS) and x-ray diffraction (µXRD) have shown the impact of degradation speed on the sites of Mg accumulation in the bone, which are around blood vessels, lacunae and the bone marrow. Only at the highest degradation rates was Mg found at the implant-bone interface. The Mg inclusion into the bone matrix appeared to be non-permanent as the Mg-level decreased after completed implant degradation. µSAXS and µXRD showed that Mg influences the hydroxyl apatite (HAP) crystallite structure, because markedly shorter and thinner HAP crystallites were found in zones of high Mg concentration. These zones also exhibited a contraction of the HAP lattice and lower crystalline order.


Assuntos
Materiais Biocompatíveis , Osso e Ossos/metabolismo , Magnésio/metabolismo , Minerais/metabolismo , Animais , Calcificação Fisiológica , Magnésio/farmacocinética , Ratos , Ratos Sprague-Dawley , Difração de Raios X
17.
Acta Biomater ; 31: 448-457, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26621693

RESUMO

Understanding the implant-bone interaction is of prime interest for the development of novel biodegrading implants. Magnesium is a very promising material in the class of biodegrading metallic implants, owing to its mechanical properties and excellent immunologic response during healing. However, the influence of degrading Mg implants on the bone nanostructure is still an open question of crucial importance for the design of novel Mg implant alloys. This study investigates the changes in the nanostructure of bone following the application of a degrading WZ21 Mg implant (2wt% Y, 1wt% Zn, 0.25wt% Ca and 0.15wt% Mn) in a murine model system over the course of 15months by small angle X-ray scattering. Our investigations showed a direct response of the bone nanostructure after as little as 1month with a realignment of nano-sized bone mineral platelets along the bone-implant interface. The growth of new bone tissue after implant resorption is characterized by zones of lower mineral platelet thickness and slightly decreased order in the stacking of the platelets. The preferential orientation of the mineral platelets strongly deviates from the normal orientation along the shaft and still roughly follows the implant direction after 15months. We explain our findings by considering geometrical, mechanical and chemical factors during the process of implant resorption. STATEMENT OF SIGNIFICANCE: The advancement of surgical techniques and the increased life expectancy have caused a growing demand for improved bone implants. Ideally, they should be bio-resorbable, support bone as long as necessary and then be replaced by healthy bone tissue. Magnesium is a promising candidate for this purpose. Various studies have demonstrated its excellent mechanical performance, degradation behaviour and immunologic properties. The structural response of bone, however, is not well known. On the nanometer scale, the arrangement of collagen fibers and calcium mineral platelets is an important indicator of structural integrity. The present study provides insight into nanostructural changes in rat bone at different times after implant placement and different implant degradation states. The results are useful for further improved magnesium alloys.


Assuntos
Implantes Absorvíveis , Osso e Ossos/química , Magnésio/química , Ligas , Animais , Materiais Biocompatíveis/química , Reabsorção Óssea , Corrosão , Masculino , Teste de Materiais , Nanoestruturas/química , Polimetil Metacrilato/química , Ratos , Ratos Sprague-Dawley , Espalhamento de Radiação , Raios X
18.
Oncogene ; 35(36): 4675-88, 2016 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-26829052

RESUMO

Protein synthesis activity is abnormally enhanced in cancer cells to support their uncontrolled growth. However, this process needs to be tightly restricted under metabolic stress-a condition often found within the tumor microenvironment-to preserve cell viability. mTORC1 is critical to link protein synthesis activity to nutrient and oxygen levels, in part by controlling the 4E-BP1-eIF4E axis. Whereas mTORC1 and eIF4E are known pro-tumorigenic factors, whose expression or activity is increased in numerous cancers, the role of 4E-BP1 in cancer is not yet definitive. On the one hand, 4E-BP1 has tumor suppressor activity by inhibiting eIF4E and, thus, blocking mRNA translation and proliferation. This is corroborated by elevated levels of phosphorylated and hence inactive 4E-BP1, which are detected in various cancers. On the other hand, 4E-BP1 has pro-tumorigenic functions as it promotes tumor adaptation to metabolic and genotoxic stress by selectively enhancing or preventing the translation of specific transcripts. Here we describe the molecular and cellular functions of 4E-BP1 and highlight the distinct roles of 4E-BP1 in cancer depending on the microenvironmental context of the tumor.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Fator de Iniciação 4E em Eucariotos/genética , Neoplasias/genética , Fosfoproteínas/genética , Biossíntese de Proteínas , Carcinogênese/genética , Proteínas de Ciclo Celular , Proliferação de Células/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias/patologia , Fosforilação , Ligação Proteica , RNA Mensageiro/genética , Transdução de Sinais
20.
J Invest Dermatol ; 102(6): 838-42, 1994 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8006445

RESUMO

To assess the potential role of interleukin (IL)-7 in immunotherapy of human malignant melanoma, we have examined the lymphokine-activated killer (LAK) cell sensitivity of four human melanoma cell lines against LAK cells generated by IL-7 or IL-2. Lysis was determined by a 24-h cytotoxicity test using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT). All melanoma cell lines were susceptible to IL-7- and IL-2-generated LAK cells. The sensitivity of melanoma cells to IL-2-induced LAK cells was higher compared to IL-7-induced LAK cells. At an effector target ratio of 20:1, the lysis by IL-7-induced LAK cells ranged between 41% and 52%, whereas IL-2-induced lysis ranged between 80% and 94% (p < 0.01). IL-7-induced LAK cells, however, showed almost no cytotoxicity towards HaCat keratinocytes and human umbilical vein endothelial cells (HUVECs). Immunophenotyping revealed a higher expression of the tac antigen (CD 25) on IL-7-generated LAK cells, particularly those cells that were CD 56 negative or CD 3 positive compared to IL-2-induced LAK cells. In contrast, IL-2-generated LAK cells killed 62% of the HaCat keratinocytes and 60% of the HUVECs. Secretion of tumor necrosis factor-alpha into culture supernatants was significantly higher in IL-2-generated LAK cells compared to IL-7-stimulated LAK cells (p < 0.01), whereas TNF-alpha levels of IL-7-induced LAK cells were in the range of unstimulated lymphocytes. Because nonspecific cytotoxicity against other normal cells such as keratinocytes and endothelial cells contributes to the dose-limiting side effects of immunotherapy with IL-2, immunotherapy using IL-7 might be a better tolerated future alternative.


Assuntos
Endotélio Vascular/citologia , Interleucina-7/farmacologia , Queratinócitos/citologia , Células Matadoras Ativadas por Linfocina/efeitos dos fármacos , Células Matadoras Ativadas por Linfocina/imunologia , Melanoma/patologia , Morte Celular , Linhagem Celular , Citotoxicidade Imunológica , Relação Dose-Resposta a Droga , Citometria de Fluxo , Humanos , Imunofenotipagem , Interleucina-2/farmacologia , Leucócitos/metabolismo , Receptores de Interleucina-2/análise , Fatores de Tempo , Células Tumorais Cultivadas , Fator de Necrose Tumoral alfa/metabolismo
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