RESUMO
Noncompliance with therapy is a big obstacle to successful therapy. We aimed to evaluate the prevalence and risk factors affecting the compliance of pediatric cancer patients with therapy in a tertiary care center far away from the capital in a lower-middle income country (LMIC). A retrospective cohort study of reports of all pediatric cancer patients who were diagnosed and started treatment between 2006 and 2010 at South Egypt Cancer Institute (SECI) was done. The following data were collected: Age, sex, diagnosis, compliance with therapy, and data on potential risk factors that might affect compliance, including time duration of travel from the patient's home to SECI, time lag between the first symptom until the first visit to SECI and until the start of treatment, results of reevaluation after the initial course of therapy, and therapy-related severe adverse events. Noncompliance with therapy was defined as when patients missed their determined therapy appointment for one week or more or abandoned therapy. This study included 510 patients. Eighty-three (16.3%) were non-compliant, as forty patients missed their therapy appointment (7.8%), and 43 abandoned further therapy (8.4%). Noncompliance was found to be more prevalent among patients with solid tumors. Non-compliant patients suffered a significantly higher relapse rate (47.7% vs. 11.2% in compliant patients, p < .001). Unfortunately, 75% of the abandoned patients who returned for further therapy suffered a relapse. Noncompliance with treatment is still a big problem facing cancer management in LMICs.
Assuntos
Países em Desenvolvimento , Neoplasias , Criança , Humanos , Estudos Retrospectivos , Cooperação do Paciente , Neoplasias/tratamento farmacológico , Neoplasias/epidemiologia , RecidivaRESUMO
BACKGROUND: Long-term survival of high-risk neuroblastoma patients is still below 50% despite intensive multimodal treatment. This trial aimed to address whether the addition of two topotecan-containing chemotherapy courses compared to standard induction therapy improves event-free survival (EFS) of these patients. PATIENTS AND METHODS: An open-label, multicenter, prospective randomized controlled trial was carried out at 58 hospitals in Germany and Switzerland. Patients aged 1-21 years with stage 4 neuroblastoma and patients aged 6 months to 21 years with MYCN-amplified tumors were eligible. The primary endpoint was EFS. Patients were randomly assigned to standard induction therapy with six chemotherapy courses or to experimental induction chemotherapy starting with two additional courses of topotecan, cyclophosphamide, and etoposide followed by standard induction chemotherapy (eight courses in total). After induction chemotherapy, all patients received high-dose chemotherapy with autologous hematopoietic stem cell rescue and isotretinoin for consolidation. Radiotherapy was applied to patients with active tumors at the end of induction chemotherapy. RESULTS: Of 536 patients enrolled in the trial, 422 were randomly assigned to the control arm (n = 211) and the experimental arm (n = 211); the median follow-up time was 3.32 years (interquartile range 1.65-5.92). At data lock, the 3-year EFS of experimental and control patients was 34% and 32% [95% confidence Interval (CI) 28% to 40% and 26% to 38%; P = 0.258], respectively. Similarly, the 3-year overall survival of the patients did not differ [54% and 48% (95% CI 46% to 62% and 40% to 56%), respectively; P = 0.558]. The response to induction chemotherapy was not different between the arms. The median number of non-fatal toxicities per patient was higher in the experimental group while the median number of toxicities per chemotherapy course was not different. CONCLUSION: While the burden for the patients was increased by prolonging the induction chemotherapy and the toxicity, the addition of two topotecan-containing chemotherapy courses did not improve the EFS of high-risk neuroblastoma patients and thus cannot be recommended. CLINICAL TRIALS. GOV NUMBER: NCT number 03042429.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica , Quimioterapia de Indução , Neuroblastoma , Adolescente , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Criança , Pré-Escolar , Intervalo Livre de Doença , Alemanha , Humanos , Lactente , Neuroblastoma/tratamento farmacológico , Estudos Prospectivos , Suíça , Resultado do Tratamento , Adulto JovemRESUMO
The biomineralization pathway of magnetite in magnetotactic bacteria is still poorly understood and a matter of intense debates. In particular, the existence, nature, and location of possible mineral precursors of magnetite are not clear. One possible precursor has been suggested to be ferritin-bound ferrihydrite. To clarify its role for magnetite biomineralization, we analyzed and characterized ferritin-like proteins from the magnetotactic alphaproteobacterium Magnetospirillum gryphiswaldense MSR-1, employing genetic, biochemical, and spectroscopic techniques. Transmission Mössbauer spectroscopy of the wild type (WT) and a bacterioferritin (bfr) deletion strain uncovered that the presence of ferrihydrite in cells is coupled to the presence of Bfr. However, bfr and dps deletion mutants, encoding another ferritin-like protein, or even mutants with their codeletion had no impact on magnetite formation in MSR-1. Thus, ferritin-like proteins are not involved in magnetite biomineralization and Bfr-bound ferrihydrite is not a precursor of magnetite biosynthesis. Using transmission electron microscopy and bacterial two-hybrid and electrophoretic methods, we also show that MSR-1 Bfr is an atypical representative of the Bfr subfamily, as it forms tetraeicosameric complexes from two distinct subunits. Furthermore, our analyses revealed that these subunits are functionally divergent, with Bfr1 harboring a ferroxidase activity while only Bfr2 contributes to heme binding. Because of this functional differentiation and the poor formation of homooligomeric Bfr1 complexes, only heterooligomeric Bfr protects cells from oxidative stress in vivo. In summary, our results not only provide novel insights into the biomineralization of magnetite but also reveal the unique properties of so-far-uncharacterized heterooligomeric bacterioferritins.IMPORTANCE Magnetotactic bacteria like Magnetospirillum gryphiswaldense are able to orient along magnetic field lines due to the intracellular formation of magnetite nanoparticles. Biomineralization of magnetite has been suggested to require a yet-unknown ferritin-like ferrihydrite component. Here, we report the identification of a bacterioferritin as the source of ferrihydrite in M. gryphiswaldense and show that, contrary to previous reports, bacterioferritin is not involved in magnetite biomineralization but required for oxidative stress resistance. Additionally, we show that bacterioferritin of M. gryphiswaldense is an unusual member of the bacterioferritin subfamily as it is composed of two functionally distinct subunits. Thus, our findings extend our understanding of the bacterioferritin subfamily and also solve a longstanding question about the magnetite biomineralization pathway.
Assuntos
Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Biomineralização , Grupo dos Citocromos b/química , Grupo dos Citocromos b/metabolismo , Ferritinas/química , Ferritinas/metabolismo , Óxido Ferroso-Férrico/metabolismo , Magnetospirillum/química , Magnetospirillum/metabolismo , Proteínas de Bactérias/genética , Grupo dos Citocromos b/deficiência , Grupo dos Citocromos b/genética , Compostos Férricos/metabolismo , Ferritinas/deficiência , Ferritinas/genética , Deleção de Genes , Magnetospirillum/genética , Redes e Vias Metabólicas/genéticaRESUMO
AIM OF THE STUDY: Radiolabelled meta-iodobenzylguanidine (MIBG) is an effective option in treatment of neuroblastoma (NBL) tumours. We studied feasibility, toxicity and efficacy of upfront 131I-MIBG and induction treatment in stage 4 NBL patients. PATIENTS AND METHODS: Retrospective, multi-centre (AMC and EMC) pilot regimen (1/1/2005-2011). Newly diagnosed stage 4 NBL patients, were treated with 2 courses of 131I-MIBG, GPOH 2004 NBL protocol, myeloablative therapy (MAT) and autologous stem cell rescue (ASCT). 131I-MIBG was administered in a fixed dose. Response rate (RR) was defined as complete remission, very good partial response and partial response. RESULTS: Thirty-two patients, (median age [range] 2.9 [0-11.4] years), 21 received 131I-MIBG therapy, 11 did not because of: MIBG non-avid (N = 5) and poor clinical condition (N = 6). In 95% of eligible patients 131I-MIBG treatment was feasible within 2 weeks from diagnosis. Interval between chemotherapy courses was 25 days (131I-MIBG group) versus 22 days (chemotherapy group). No stem cell support was needed after 131I-MIBG therapy. Stem cell harvest in both groups was feasible, neutrophil recovery was comparable, but platelet recovery post MAT, ASCT was slower for 131I-MIBG-treated patients. RR post 131I-MIBG was 38%, post MAT + ASCT was 71% (131I-MIBG group), 36% (chemotherapy group) and overall 59%. CONCLUSIONS: Induction therapy with 131I-MIBG before the HR GPOH NB 2004 protocol is feasible, tolerable and effective in newly diagnosed stage 4 NBL patients. 131I-MIBG upfront therapy induces early responses.
Assuntos
3-Iodobenzilguanidina/uso terapêutico , Neoplasias Abdominais/tratamento farmacológico , Antineoplásicos/uso terapêutico , Quimioterapia de Indução/métodos , Agonistas Mieloablativos/uso terapêutico , Neuroblastoma/tratamento farmacológico , Transplante de Células-Tronco , Neoplasias Torácicas/tratamento farmacológico , Neoplasias Abdominais/patologia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Criança , Pré-Escolar , Estudos de Viabilidade , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Estadiamento de Neoplasias , Neuroblastoma/patologia , Projetos Piloto , Estudos Retrospectivos , Procedimentos Cirúrgicos Operatórios , Neoplasias Torácicas/patologia , Fatores de Tempo , Transplante AutólogoRESUMO
BACKGROUND: Neuroblastoma is a rare malignant disease and patients with high-risk neuroblastoma have a poor prognosis. Rapid COJEC induction chemotherapy means (almost) the same total doses given within a shorter time period. In theory, rapid COJEC could reduce the risk of drug resistance and it has been considered as a potential candidate for improving the outcome. METHODS: The objective was to evaluate effects of rapid COJEC compared to standard induction chemotherapy in patients with high-risk neuroblastoma. We searched the databases CENTRAL, MEDLINE, and EMBASE from inception to 11 November 2014 and included randomized controlled trials. RESULTS: We identified one relevant randomized controlled trial with 130 participants receiving rapid COJEC and 132 participants receiving standard OPEC/COJEC induction chemotherapy. There was no statistically significant difference between the treatment groups in complete response (risk ratio 0.99, 95% confidence interval 0.71 to 1.38, P=0.94) and treatment-related mortality (risk ratio 1.21, 95% confidence interval 0.33 to 4.39, P=0.77). A statistically significant difference in favor of the standard treatment arm was identified for the following early toxicities: febrile neutropenia, septicemia, and renal toxicity. CONCLUSION: The differences in complete response and treatment-related mortality between treatment alternatives were not statistically significantly different. Based on the currently available evidence, we are uncertain about the effects of rapid COJEC induction chemotherapy in patients with high-risk neuroblastoma.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Terapia Neoadjuvante , Neuroblastoma/tratamento farmacológico , Adolescente , Carboplatina/administração & dosagem , Carboplatina/uso terapêutico , Cisplatino/administração & dosagem , Cisplatino/uso terapêutico , Ciclofosfamida/administração & dosagem , Ciclofosfamida/uso terapêutico , Esquema de Medicação , Etoposídeo/administração & dosagem , Etoposídeo/uso terapêutico , Feminino , Humanos , Masculino , Neuroblastoma/mortalidade , Neuroblastoma/patologia , Ensaios Clínicos Controlados Aleatórios como Assunto , Medição de Risco , Taxa de Sobrevida , Vincristina/administração & dosagem , Vincristina/uso terapêutico , Adulto JovemRESUMO
BACKGROUND: Neuroblastoma is a rare malignant disease and patients with high-risk neuroblastoma have a poor prognosis. Retinoic acid has been shown to inhibit growth of human neuroblastoma cells and has been considered as a potential candidate for improving the outcome. METHODS: The objective was to evaluate effects of retinoic acid after consolidation with high-dose chemotherapy and bone marrow transplantation as compared to placebo or no further treatment in patients with high-risk neuroblastoma. We searched the databases CENTRAL, MEDLINE, and EMBASE from inception to 01 October 2014 and included randomized controlled trials. RESULTS: We identified one relevant randomized controlled trial with 50 participants receiving retinoic acid and 48 participants receiving no further therapy. There was no statistically significant difference between the treatment groups in overall survival (hazard ratio 0.87, 95% confidence interval 0.46-1.63, P=0.66) and event-free survival (hazard ratio 0.86, 95% confidence interval 0.50-1.49, P=0.59). We did not identify results for other outcomes, including toxicity. CONCLUSION: The difference in overall and event-free survival between treatment alternatives was not statistically significantly different. Based on the currently available evidence, we are uncertain about the effects of retinoic acid after bone marrow transplantation in patients with high-risk neuroblastoma.
Assuntos
Transplante de Medula Óssea , Neuroblastoma/terapia , Medição de Risco , Tretinoína/uso terapêutico , Quimioterapia Adjuvante , Criança , Pré-Escolar , Terapia Combinada , Intervalo Livre de Doença , Humanos , Lactente , Recém-Nascido , Estadiamento de Neoplasias , Neuroblastoma/mortalidade , Neuroblastoma/patologia , Prognóstico , Ensaios Clínicos Controlados Aleatórios como AssuntoRESUMO
BACKGROUND: Central nervous system (CNS) and non-CNS embryonal tumors occur principally in children and are rarely seen in adults. The incidence rates for rare entities such as atypical teratoid/rhabdoid tumors (AT/RT) or primitive neuroectodermal tumors in the CNS are rarely published. Incidence rates for certain subgroups, such as hepatoblastomas, have been increasing in some countries. METHODS: Data of 8337 embryonal tumors, registered in children (0-14 years) between 1991 and 2012 (for AT/RT 2000-2012) in the population-based German Childhood Cancer Registry with complete national coverage were analyzed for incidence rates, time trends, and survival. RESULTS: For most entities, the incidence rates were the highest for children <1 year. An important exception was medulloblastomas, which occurred mainly in 1- to 9-year-olds. Neuroblastomas and ganglioneuroblastomas as well as Wilms tumors (nephroblastomas) had the highest age standardized incidence rates (13.7 and 9.4 per million, respectively). A statistically significant increasing trend for hepatoblastomas (annual average percent change 4.6%) was detected. The survival probabilities varied between the diagnostic groups: primitive neuroectodermal tumors and AT/RT had the lowest and retinoblastomas the highest. The survival was dependent on the age at diagnosis, the most extreme examples being neuroblastomas, for which the survival probability declined steeply for children ≥1 year and medulloblastomas, for which the highest survival was seen for 10- to 14-year-olds. CONCLUSIONS: This study presents a comprehensive overview of pediatric embryonal tumors from a well-established, complete nationwide cancer registry. Significant increasing trend for hepatoblastomas was detected for the first time in Europe.
Assuntos
Neoplasias do Sistema Nervoso Central/diagnóstico , Neoplasias do Sistema Nervoso Central/epidemiologia , Neoplasias Embrionárias de Células Germinativas/diagnóstico , Neoplasias Embrionárias de Células Germinativas/epidemiologia , Adolescente , Neoplasias do Sistema Nervoso Central/mortalidade , Criança , Pré-Escolar , Feminino , Alemanha/epidemiologia , Humanos , Incidência , Lactente , Recém-Nascido , Masculino , Neoplasias Embrionárias de Células Germinativas/mortalidade , Sistema de Registros , Taxa de Sobrevida/tendênciasRESUMO
Although the iron uptake and storage mechanisms of terrestrial/higher plants have been well studied, the corresponding systems in marine algae have received far less attention. Studies have shown that while some species of unicellular algae utilize unique mechanisms of iron uptake, many acquire iron through the same general mechanisms as higher plants. In contrast, the iron acquisition strategies of the multicellular macroalgae remain largely unknown. This is especially surprising since many of these organisms represent important ecological and evolutionary niches in the coastal marine environment. It has been well established in both laboratory and environmentally derived samples, that a large amount of iron can be 'non-specifically' adsorbed to the surface of marine algae. While this phenomenon is widely recognized and has prompted the development of experimental protocols to eliminate its contribution to iron uptake studies, its potential biological significance as a concentrated iron source for marine algae is only now being recognized. This study used an interdisciplinary array of techniques to explore the nature of the extensive and powerful iron binding on the surface of both laboratory and environmental samples of the marine brown alga Ectocarpus siliculosus and shows that some of this surface-bound iron is eventually internalized. It is proposed that the surface-binding properties of E. siliculosus allow it to function as a quasibiological metal ion 'buffer', allowing iron uptake under the widely varying external iron concentrations found in coastal marine environments.
Assuntos
Ferro/metabolismo , Phaeophyceae/metabolismo , Soluções Tampão , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Ácido Edético/farmacologia , Compostos Ferrosos/farmacologia , Íons , Cinética , Phaeophyceae/citologia , Phaeophyceae/efeitos dos fármacos , Phaeophyceae/ultraestrutura , Espectrometria por Raios X , Espectroscopia de Mossbauer , Termodinâmica , Fatores de TempoRESUMO
In Germany and Austria, more than 90% of pediatric cancer patients are enrolled into nationwide disease-specific first-line clinical trials or interim registries. Essential components are a pediatric cancer registry and centralized reference laboratories, imaging review, and tumor board assistance. The five-year overall survival rate in countries where such infrastructures are established has improved from <20% before 1950 to >80% since 1995. Today, treatment intensity is tailored to the individual patient's risk to provide the highest chances of survival while minimizing deleterious late effects. Multicenter clinical trials are internationalized and serve as platforms for further improvements by novel drugs and biologicals.
Assuntos
Neoplasias , Sistema de Registros , Adolescente , Áustria/epidemiologia , Criança , Pré-Escolar , Ensaios Clínicos como Assunto/história , Ensaios Clínicos como Assunto/métodos , Intervalo Livre de Doença , Feminino , Alemanha/epidemiologia , História do Século XX , História do Século XXI , Humanos , Lactente , Masculino , Estudos Multicêntricos como Assunto/história , Estudos Multicêntricos como Assunto/métodos , Neoplasias/diagnóstico , Neoplasias/mortalidade , Neoplasias/terapia , Taxa de SobrevidaRESUMO
Neuroblastoma is an embryonal malignancy of the sympathetic nervous system. Spontaneous regression and differentiation of neuroblastoma is observed in a subset of patients, and has been suggested to represent delayed activation of physiologic molecular programs of fetal neuroblasts. Homeobox genes constitute an important family of transcription factors, which play a fundamental role in morphogenesis and cell differentiation during embryogenesis. In this study, we demonstrate that expression of the majority of the human HOX class I homeobox genes is significantly associated with clinical covariates in neuroblastoma using microarray expression data of 649 primary tumors. Moreover, a HOX gene expression-based classifier predicted neuroblastoma patient outcome independently of age, stage and MYCN amplification status. Among all HOX genes, HOXC9 expression was most prominently associated with favorable prognostic markers. Most notably, elevated HOXC9 expression was significantly associated with spontaneous regression in infant neuroblastoma. Re-expression of HOXC9 in three neuroblastoma cell lines led to a significant reduction in cell viability, and abrogated tumor growth almost completely in neuroblastoma xenografts. Neuroblastoma growth arrest was related to the induction of programmed cell death, as indicated by an increase in the sub-G1 fraction and translocation of phosphatidylserine to the outer membrane. Programmed cell death was associated with the release of cytochrome c from the mitochondria into the cytosol and activation of the intrinsic cascade of caspases, indicating that HOXC9 re-expression triggers the intrinsic apoptotic pathway. Collectively, our results show a strong prognostic impact of HOX gene expression in neuroblastoma, and may point towards a role of Hox-C9 in neuroblastoma spontaneous regression.
Assuntos
Regulação Neoplásica da Expressão Gênica , Proteínas de Homeodomínio/genética , Regressão Neoplásica Espontânea/genética , Neoplasias do Sistema Nervoso/genética , Neuroblastoma/genética , Apoptose/genética , Caspases/genética , Caspases/metabolismo , Diferenciação Celular , Linhagem Celular Tumoral , Pré-Escolar , Citocromos c/metabolismo , Proteínas de Homeodomínio/metabolismo , Humanos , Lactente , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Proteína Proto-Oncogênica N-Myc , Estadiamento de Neoplasias , Neoplasias do Sistema Nervoso/metabolismo , Neoplasias do Sistema Nervoso/mortalidade , Neoplasias do Sistema Nervoso/patologia , Neuroblastoma/metabolismo , Neuroblastoma/mortalidade , Neuroblastoma/patologia , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteínas Oncogênicas/genética , Proteínas Oncogênicas/metabolismo , Prognóstico , Transdução de Sinais , Análise de Sobrevida , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The iron uptake and storage systems of terrestrial/higher plants are now reasonably well understood with two basic strategies being distinguished: strategy I involves the induction of a Fe(III)-chelate reductase (ferrireductase) along with Fe(II) or Fe(III) transporter proteins while strategy II plants have evolved sophisticated systems based on high-affinity, iron specific, binding compounds called phytosiderophores. In contrast, there is little knowledge about the corresponding systems in marine, plant-like lineages. Herein we report a study of the iron uptake and storage mechanisms in the green alga Tetraselmis suecica. Short term radio-iron uptake studies indicate that iron is taken up by Tetraselmis in a time and concentration dependent manner consistent with an active transport process. Based on inhibitor and other studies it appears that a reductive-oxidative pathway such as that found in yeast and the green alga Chlamydomonas reinhardtii is likely. Upon long term exposure to (57)Fe we have been able, using a combination of Mössbauer and X-ray absorption spectroscopies, to identify three metabolites. The first exhibits Mössbauer parameters typical of a [Fe(4)S(4)](2+) cluster and which accounts for approximately 10% of the total intracellular iron pool. The second displays a spectrum typical of a [Fe(II)O(6)] system accounting for approximately 2% of the total pool. The largest component (ca. 85+%) consists of polymeric iron-oxo mineral species with parameters between that of the crystalline ferrihydrite core of animal ferritins and the amorphous hydrated ferric phosphate of bacterial and plant ferritins.
Assuntos
Clorófitas/metabolismo , Ferro/metabolismo , Biologia Marinha , Transporte Biológico , Espectroscopia de Mossbauer , Espectroscopia por Absorção de Raios XRESUMO
Iron is an essential element for all living organisms due to its ubiquitous role in redox and other enzymes, especially in the context of respiration and photosynthesis. The iron uptake and storage systems of terrestrial/higher plants are now reasonably well understood with two basic strategies for iron uptake being distinguished: strategy I plants use a mechanism involving soil acidification and induction of Fe(III)-chelate reductase (ferrireductase) and Fe(II) transporter proteins while strategy II plants have evolved sophisticated systems based on high-affinity, iron specific, binding compounds called phytosiderophores. In contrast, there is little knowledge about the corresponding systems in marine plant-like lineages. Herein we report a study of the iron uptake and storage mechanisms in the coccolithophore Emiliania huxleyi. Short term radio-iron uptake studies indicate that iron is taken up by Emiliania in a time and concentration dependent manner consistent with an active transport process. Based on inhibitor studies it appears that iron is taken up directly as Fe(iii). However if a reductive step is involved the Fe(II) must not be accessible to the external environment. Upon long term exposure to (57)Fe we have been able, using a combination of Mössbauer and XAS spectroscopies, to identify a single metabolite which displays spectral features similar to the phosphorus-rich mineral core of bacterial and plant ferritins.
Assuntos
Haptófitas/química , Haptófitas/metabolismo , Ferro/química , Ferro/metabolismo , Transporte Biológico , Haptófitas/enzimologia , Isótopos de Ferro/química , Isótopos de Ferro/metabolismo , Proteínas de Ligação ao Ferro , Proteínas de Membrana , Oxirredução , Oxirredutases/química , Oxirredutases/metabolismo , Análise EspectralRESUMO
Iron is an essential element for all living organisms due to its ubiquitous role in redox and other enzymes, especially in the context of respiration and photosynthesis. The iron uptake and storage systems of terrestrial/higher plants are now reasonably well understood, with two basic strategies for iron uptake being distinguished: strategy I plants use a mechanism involving induction of Fe(III)-chelate reductase (ferrireductase) and Fe(II) transporter proteins, while strategy II plants utilize high-affinity, iron-specific, binding compounds called phytosiderophores. In contrast, little is known about the corresponding systems in marine, plant-like lineages, particularly those of multicellular algae (seaweeds). Herein the first study of the iron uptake and storage mechanisms in the brown alga Ectocarpus siliculosus is reported. Genomic data suggest that Ectocarpus may use a strategy I approach. Short-term radio-iron uptake studies verified that iron is taken up by Ectocarpus in a time- and concentration-dependent manner consistent with an active transport process. Upon long-term exposure to (57)Fe, two metabolites have been identified using a combination of Mössbauer and X-ray absorption spectroscopies. These include an iron-sulphur cluster accounting for ~26% of the total intracellular iron pool and a second component with spectra typical of a polymeric (Fe(3+)O(6)) system with parameters similar to the amorphous phosphorus-rich mineral core of bacterial and plant ferritins. This iron metabolite accounts for ~74% of the cellular iron pool and suggests that Ectocarpus contains a non-ferritin but mineral-based iron storage pool.
Assuntos
Ferro/metabolismo , Phaeophyceae/metabolismo , Absorciometria de Fóton , Genômica , Transporte de Íons , Phaeophyceae/química , Phaeophyceae/genética , Proteínas/genética , Proteínas/metabolismoRESUMO
Bacteria use small diffusible molecules to exchange information in a process called quorum sensing (QS). An important class of quorum sensing molecules used by Gram-negative bacteria is the family of N-acylhomoserine lactones (HSL). It was recently discovered that a degradation product of the QS molecule 3-oxo-C(12)-homoserine lactone, the tetramic acid 3-(1-hydroxydecylidene)-5-(2-hydroxyethyl)pyrrolidine-2,4-dione, is a potent antibacterial agent, thus implying roles for QS outside of simply communication. Because these tetramic acids also appear to bind iron with appreciable affinity it was suggested that metal binding might contribute to their biological activity. Here, using a variety of spectroscopic tools, we describe the coordination chemistry of both the methylidene and decylidene tetramic acid derivatives with Fe(III) and Ga(III) and discuss the potential biological significance of such metal binding.
Assuntos
4-Butirolactona/análogos & derivados , Antibacterianos/química , Complexos de Coordenação/química , Gálio/química , Ferro/química , Succinimidas/química , 4-Butirolactona/química , Antibacterianos/farmacologia , Complexos de Coordenação/farmacologia , Eletroquímica , Concentração de Íons de Hidrogênio , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Percepção de Quorum , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Succinimidas/farmacologiaRESUMO
AIMS: To evaluate the efficacy of interstitial brachytherapy using (125)iodine ((125)I) seeds for the treatment of recurrent multimodal treated medulloblastoma. MATERIALS AND METHODS: Between September 1989 and August 2009, 12 patients (female:male=3:9, median age 19 years, range 7-55 years) with 23 recurrent medulloblastomas underwent interstitial brachytherapy using (125)I seeds. Before brachytherapy, all patients underwent microsurgical resection; six patients underwent a combined adjuvant treatment consisting of craniospinal irradiation and chemotherapy; three received craniospinal irradiation alone and two received chemotherapy alone. One patient was treated by surgery alone. The median tumour volume was 4.9ml (range 0.4-44.2ml), the median tumour surface dose 50Gy (range 32-50Gy) and the median implantation time 42 days (range 42-90 days). A median follow-up of 26 months was available (range 5-116 months). RESULTS: After brachytherapy, nine of 23 tumours (39%) presented a complete remission, nine (39%) a partial remission and five (22%) stable disease on magnetic resonance images. The neurological status improved in six patients and remained unchanged in four. Two patients deteriorated: one developed spinal metastasis and another a treatment-related adverse radiation effect. Ten patients died due to disseminated disease despite local tumour control. The median survival after treatment was 15 months (range 5-68 months). CONCLUSIONS: Our results show a good response of recurrent medulloblastoma after interstitial brachytherapy. High rates of tumour remission were yielded with low rates of treatment-related morbidity. Thus, (125)I seed brachytherapy should be considered as a treatment option for recurrent medulloblastoma.
Assuntos
Braquiterapia , Neoplasias Cerebelares/radioterapia , Radioisótopos do Iodo/uso terapêutico , Meduloblastoma/radioterapia , Recidiva Local de Neoplasia/radioterapia , Terapia de Salvação , Adolescente , Adulto , Neoplasias Cerebelares/patologia , Criança , Feminino , Seguimentos , Humanos , Masculino , Meduloblastoma/patologia , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/patologia , Prognóstico , Taxa de Sobrevida , Adulto JovemRESUMO
Microarray-based prediction of clinical endpoints may be performed using either a one-color approach reflecting mRNA abundance in absolute intensity values or a two-color approach yielding ratios of fluorescent intensities. In this study, as part of the MAQC-II project, we systematically compared the classification performance resulting from one- and two-color gene-expression profiles of 478 neuroblastoma samples. In total, 196 classification models were applied to these measurements to predict four clinical endpoints, and classification performances were compared in terms of accuracy, area under the curve, Matthews correlation coefficient and root mean-squared error. Whereas prediction performance varied with distinct clinical endpoints and classification models, equivalent performance metrics were observed for one- and two-color measurements in both internal and external validation. Furthermore, overlap of selected signature genes correlated inversely with endpoint prediction difficulty. In summary, our data strongly substantiate that the choice of platform is not a primary factor for successful gene expression based-prediction of clinical endpoints.
Assuntos
Neoplasias Encefálicas/genética , Determinação de Ponto Final/métodos , Perfilação da Expressão Gênica/métodos , Neuroblastoma/genética , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Algoritmos , Área Sob a Curva , Inteligência Artificial , Cor , Bases de Dados Genéticas , Humanos , Análise dos Mínimos Quadrados , Valor Preditivo dos Testes , Controle de Qualidade , RNA Neoplásico/genética , Curva ROCAssuntos
Anticorpos Antibacterianos/sangue , Antineoplásicos/toxicidade , Neoplasias Ósseas/tratamento farmacológico , Neoplasias Ósseas/imunologia , Difteria/imunologia , Osteossarcoma/tratamento farmacológico , Osteossarcoma/imunologia , Sarcoma/tratamento farmacológico , Sarcoma/imunologia , Neoplasias de Tecidos Moles/tratamento farmacológico , Neoplasias de Tecidos Moles/imunologia , Tétano/imunologia , Adolescente , Fatores Etários , Antineoplásicos/uso terapêutico , Criança , Pré-Escolar , Feminino , Humanos , Tolerância Imunológica/imunologia , Masculino , Infecções Oportunistas/imunologia , Vigilância da População , Estudos Prospectivos , Sistema de Registros , Fatores de RiscoRESUMO
RECQL4 mutations cause genetic instability and increase the risk of malignant disease. We report on a patient with compound heterozygosity for two novel RECQL4 mutations: mutation c.1919_1924delTCACAG, p.L640_A642delinsP in exon 12 of the RECQL4 gene and mutation c.1704+1G>A in intron 10 of the RECQL4 gene. He subsequently developed large cell anaplastic T cell lymphoma at the age of 9 years, diffuse large cell B lymphoma and osteosarcoma when he was 14 years old, and finally acute lymphatic leukemia when he was 21 years old. The most remarkable clinical features are young age, spontaneous remission of diffuse large cell lymphoma, and severe CNS and skin toxicity of cytotoxic treatment.
Assuntos
Neoplasias Ósseas/genética , Leucemia Linfocítica Granular Grande/genética , Linfoma Difuso de Grandes Células B/genética , Osteossarcoma/genética , RecQ Helicases/genética , Síndrome de Rothmund-Thomson/genética , Evolução Fatal , Heterozigoto , Humanos , Masculino , Mutação , Regressão Neoplásica Espontânea , Adulto JovemRESUMO
Imbalances in chromosome 11q occur in approximately 30% of primary neuroblastoma and are associated with poor outcome. It has been suggested that 11q loss constitutes a distinct clinico-genetic neuroblastoma subgroup by affecting expression levels of corresponding genes. This study analysed the relationship of 11q loss, clinical phenotype and global transcriptomic profiles in four clinico-genetic subgroups (11q alteration/favourable outcome, n=7; 11q alteration/unfavourable outcome, n=14; no 11q alteration/favourable outcome, n=81; no 11q alteration/unfavourable outcome, n=8; tumours with MYCN amplification and/or 1p loss were excluded). Unsupervised and supervised comparisons of gene expression profiles consistently showed significantly different mRNA patterns between favourable and unfavourable neuroblastomas, both in the subgroups with and without 11q loss. In contrast, favourable tumours with and without 11q loss showed highly similar transcriptomic profiles. Disproportionate downregulation of 11q genes was observed only in unfavourable tumours with 11q loss. The diverging molecular profiles were neither caused by considerable differences in the size of the deleted regions nor by differential methylation patterns of 11q genes. Together, this study shows that neuroblastoma with 11q loss comprises two biological subgroups that differ both in their clinical phenotype and gene expression patterns, indicating that 11q loss is not a primary determinant of neuroblastoma tumour behaviour.
Assuntos
Deleção Cromossômica , Cromossomos Humanos Par 11/genética , Biologia Computacional , Perfilação da Expressão Gênica , Genômica , Neuroblastoma/diagnóstico , Neuroblastoma/genética , Pré-Escolar , Cromossomos Humanos Par 11/metabolismo , Regulação Neoplásica da Expressão Gênica , Humanos , Metilação , Neuroblastoma/metabolismo , Neuroblastoma/patologia , Prognóstico , Regiões Promotoras Genéticas/genéticaRESUMO
BACKGROUND: The aim of this study is to elucidate the expression patterns of GATA transcription factors in neuroblastoma and the developing sympathetic nervous system (SNS). METHODS: GATA-2, -3 and -4 and their cofactor friend-of-GATA (FOG)-2 were investigated in primary neuroblastoma by immunohistochemistry, real-time RT-PCR (n=73) and microarray analysis (n=251). In addition, GATA-2, -3 and FOG-2 expression was determined by northern-blot hybridisation. In the developing murine SNS, Gata-4 and Fog-2 were examined by immunohistochemistry. RESULTS: Although Gata-2, -3 and Fog-2 are expressed in the developing nervous system, Gata-4 was not detected. In contrast, protein expression of all factors was observed in human neuroblastoma. Northern-blot hybridisation and real-time RT-PCR suggested specific expression patterns of the four genes in primary neuroblastoma, but did not show unequivocal results. In the large cohort examined by microarrays, a significant association of GATA-2, -3 and FOG-2 expression with low-risk features was observed, whereas GATA-4 mRNA levels correlated with MYCN-amplification. CONCLUSION: The transcription factors GATA-2 and -3, which are essential for normal SNS development, and their cofactor FOG-2 are downregulated in aggressive but not in favourable neuroblastoma. In contrast, upregulation of GATA-4 appears to be a common feature of this malignancy and might contribute to neuroblastoma pathogenesis.