RESUMO
In this work, we intersect data on size-selected particulate matter (PM) with vehicular traffic counts and a comprehensive set of meteorological covariates to study the effect of traffic on air quality. To this end, we develop an M-quantile regression model with Lasso and Elastic Net penalizations. This allows (i) to identify the best proxy for vehicular traffic via model selection, (ii) to investigate the relationship between fine PM concentration and the covariates at different M-quantiles of the conditional response distribution, and (iii) to be robust to the presence of outliers. Heterogeneity in the data is accounted by fitting a B-spline on the effect of the day of the year. Analytic and bootstrap-based variance estimates of the regression coefficients are provided, together with a numerical evaluation of the proposed estimation procedure. Empirical results show that atmospheric stability is responsible for the most significant effect on fine PM concentration: this effect changes at different levels of the conditional response distribution and is relatively weaker on the tails. On the other hand, model selection allows to identify the best proxy for vehicular traffic whose effect remains essentially the same at different levels of the conditional response distribution.
Assuntos
Poluentes Atmosféricos , Poluição do Ar , Poluentes Atmosféricos/efeitos adversos , Poluentes Atmosféricos/análise , Meteorologia , Monitoramento Ambiental/métodos , Poluição do Ar/efeitos adversos , Poluição do Ar/análise , Material Particulado/análiseRESUMO
In this work we propose the use of functional data analysis (FDA) to deal with a very large dataset of atmospheric aerosol size distribution resolved in both space and time. Data come from a mobile measurement platform in the town of Perugia (Central Italy). An OPC (Optical Particle Counter) is integrated on a cabin of the Minimetrò, an urban transportation system, that moves along a monorail on a line transect of the town. The OPC takes a sample of air every six seconds and counts the number of particles of urban aerosols with a diameter between 0.28 µm and 10 µm and classifies such particles into 21 size bins according to their diameter. Here, we adopt a 2D functional data representation for each of the 21 spatiotemporal series. In fact, space is unidimensional since it is measured as the distance on the monorail from the base station of the Minimetrò. FDA allows for a reduction of the dimensionality of each dataset and accounts for the high space-time resolution of the data. Functional cluster analysis is then performed to search for similarities among the 21 size channels in terms of their spatiotemporal pattern. Results provide a good classification of the 21 size bins into a relatively small number of groups (between three and four) according to the season of the year. Groups including coarser particles have more similar patterns, while those including finer particles show a more different behavior according to the period of the year. Such features are consistent with the physics of atmospheric aerosol and the highlighted patterns provide a very useful ground for prospective model-based studies.
Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Modelos Teóricos , Material Particulado/análise , Aerossóis/análise , Itália , Tamanho da Partícula , Estudos Prospectivos , Estações do AnoRESUMO
Essential In patients on treatment with direct anticoagulants (DOACs) variation of renal function is common. The effect of variations of renal function over time on major bleeding is not well defined. Variation of renal function over time is an independent predictor of major bleeding. Identifying conditions associated with variation of renal function may increase safety of DOACs. SUMMARY: Background Chronic kidney disease is a risk factor for major bleeding in patients with atrial fibrillation (AF) treated with warfarin. Objective To assess the effect of variations in renal function over time on the risk of major bleeding during treatment with direct oral anticoagulants (DOACs) in patients with non-valvular AF. Methods Consecutive AF patients were prospectively followed after they had received the first DOAC prescription. Estimated glomerular filtration rate (eGFR) was periodically assessed, and the incidence of major bleeding was recorded. A joint survival model was used to estimate the association between variation in eGFR and the risk of major bleeding. Results During a mean follow-up of 575 days, 44 major bleeds occurred in 449 patients (6.1% per patient-year). eGFR over time was inversely and independently associated with the risk of major bleeding; every 1 mL min-1 absolute decrease in eGFR was associated with a 2% increase in the risk of major bleeding (hazard ratio [HR] 1.02, 95% confidence interval [CI] 1.01-1.04). A similar effect of the variation in eGFR over time was observed on the risk of clinically relevant non-major bleeding (HR 1.02, 95% CI 1.01-1.03). Deterioration of renal function leading to a change in eGFR staging was associated with an increase in the risk of major bleeding (HR 2.43, 95% CI 1.33-4.45). Conclusions Variation in renal function over time is associated with the risk of major bleeding in AF patients treated with DOACs in real life. Identification of intervening clinical conditions associated with variation in renal function is essential to reduce the risk of major bleeding and to make DOAC treatment more safe.
Assuntos
Anticoagulantes/administração & dosagem , Anticoagulantes/efeitos adversos , Fibrilação Atrial/tratamento farmacológico , Taxa de Filtração Glomerular , Hemorragia/induzido quimicamente , Rim/fisiopatologia , Insuficiência Renal Crônica/fisiopatologia , Acidente Vascular Cerebral/prevenção & controle , Administração Oral , Idoso , Idoso de 80 Anos ou mais , Fibrilação Atrial/diagnóstico , Fibrilação Atrial/epidemiologia , Progressão da Doença , Feminino , Hemorragia/epidemiologia , Humanos , Incidência , Itália/epidemiologia , Masculino , Estudos Prospectivos , Insuficiência Renal Crônica/diagnóstico , Insuficiência Renal Crônica/epidemiologia , Medição de Risco , Fatores de Risco , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/epidemiologia , Fatores de Tempo , Resultado do TratamentoRESUMO
Epidermal development requires the transcription factor p63, as p63-/- mice are born dead, without skin. The gene expresses two proteins, one with an amino-terminal transactivation domain (TAp63) and one without (deltaNp63), although their relative contribution to epidermal development is unknown. To address this issue, we reintroduced TAp63alpha and/or deltaNp63alpha under the K5 promoter into p63-/- mice by in vivo genetic complementation. Whereas p63-/- and p63-/-;TA mice showed extremely rare patches of poorly differentiated keratinocytes, p63-/-;deltaN mice showed significant epidermal basal layer formation. Double TAp63alpha/deltaNp63alpha complementation showed greater patches of differentiated skin; at the ultrastructural level, there was clear reformation of a distinct basal membrane and hemidesmosomes. At the molecular level, deltaNp63 regulated expression of genes characteristic of the basal layer (K14), interacting (by Chip, luc assay) with the third p53 consensus site. Conversely, TAp63 transcribed the upper layer's genes (Ets-1, K1, transglutaminases, involucrin). Therefore, the two p63 isoforms appear to play distinct cooperative roles in epidermal formation.
Assuntos
Epiderme/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Fosfoproteínas/metabolismo , Pele/metabolismo , Transativadores/metabolismo , Animais , Animais Recém-Nascidos , Linhagem Celular , Proliferação de Células , Embrião de Mamíferos/metabolismo , Embrião de Mamíferos/patologia , Epiderme/embriologia , Epiderme/crescimento & desenvolvimento , Epiderme/patologia , Proteínas Filagrinas , Perfilação da Expressão Gênica/métodos , Proteínas de Filamentos Intermediários/genética , Proteínas de Filamentos Intermediários/metabolismo , Queratina-14/genética , Queratina-14/metabolismo , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Análise de Sequência com Séries de Oligonucleotídeos , Fenótipo , Fosfoproteínas/genética , Regiões Promotoras Genéticas/genética , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Pele/embriologia , Pele/crescimento & desenvolvimento , Pele/patologia , Transativadores/genética , TransfecçãoRESUMO
Type 2 diabetes is characterized by insulin resistance and inadequate insulin secretion. In the advanced stages of the disease, beta-cell dysfunction worsens and insulin therapy may be necessary to achieve satisfactory metabolic control. Studies in autopsies found decreased beta-cell mass in pancreas of people with type 2 diabetes. Apoptosis, a constitutive program of cell death modulated by the Bcl family genes, has been implicated in loss of beta-cells in animal models of type 2 diabetes. In this study, we compared the effect of 5 days' culture in high glucose concentration (16.7 mmol/l) versus normal glucose levels (5.5 mmol/l) or hyperosmolar control (mannitol 11 mmol/l plus glucose 5 mmol/l) on the survival of human pancreatic islets. Apoptosis, analyzed by flow cytometry and electron and immunofluorescence microscopy, was increased in islets cultured in high glucose (HG5) as compared with normal glucose (NG5) or hyperosmolar control (NG5+MAN5). We also analyzed by reverse transcriptase-polymerase chain reaction and Western blotting the expression of the Bcl family genes in human islets cultured in normal glucose or high glucose. The antiapoptotic gene Bcl-2 was unaffected by glucose change, whereas Bcl-xl was reduced upon treatment with HG5. On the other hand, proapoptotic genes Bad, Bid, and Bik were overexpressed in the islets maintained in HG5. To define the pancreatic localization of Bcl proteins, we performed confocal immunofluorescence analysis on human pancreas. Bad and Bid were specifically expressed in beta-cells, and Bid was also expressed, although at low levels, in the exocrine pancreas. Bik and Bcl-xl were expressed in other endocrine islet cells as well as in the exocrine pancreas. These data suggest that in human islets, high glucose may modulate the balance of proapoptotic and antiapoptotic Bcl proteins toward apoptosis, thus favoring beta-cell death.
Assuntos
Apoptose , Glucose/administração & dosagem , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/fisiologia , Apoptose/genética , Células Cultivadas , Relação Dose-Resposta a Droga , Imunofluorescência , Regulação da Expressão Gênica/fisiologia , Glucose/farmacologia , Humanos , Proto-Oncogenes/fisiologia , Distribuição Tecidual , Transcrição Gênica/fisiologiaRESUMO
A new semiparametric approach to model-based small area prediction for counts is proposed and used for estimating the average number of visits to physicians for Health Districts in Central Italy. The proposed small area predictor can be viewed as an outlier robust alternative to the more commonly used empirical plug-in predictor that is based on a Poisson generalized linear mixed model with Gaussian random effects. Results from the real data application and from a simulation experiment confirm that the proposed small area predictor has good robustness properties and in some cases can be more efficient than alternative small area approaches.
Assuntos
Pesquisas sobre Atenção à Saúde/métodos , Inquéritos Epidemiológicos/métodos , Modelos Estatísticos , Tamanho da Amostra , Idoso , Atenção à Saúde/estatística & dados numéricos , Pesquisas sobre Atenção à Saúde/estatística & dados numéricos , Nível de Saúde , Inquéritos Epidemiológicos/estatística & dados numéricos , Humanos , Itália/epidemiologia , Funções Verossimilhança , Distribuição de Poisson , Análise de Regressão , Estudos de Amostragem , Inquéritos e QuestionáriosRESUMO
We have investigated the enzymatic reduction and accumulation of vitamin C in HaCaT epithelial cells. The subcellular localization and the activities of ascorbyl free radical reductase and dehydroascorbate reductase showed that mitochondrial, microsomal and plasma membranes fractions express high levels of ascorbyl free radical reductase activity, whereas dehydroascorbate reductase activity was found at low levels only in the post microsomal supernatant. We have also investigated cell proliferation and vitamin C accumulation induced by ascorbic acid 2-phosphate. This derivative caused no inhibition of cell growth, was uptaken from the extracellular medium and accumulated as ascorbic acid in mM concentrations. These results show that HaCaT cells possess very efficient systems to maintain high levels of both intracellular and extracellular ascorbic acid. The regeneration and uptake of ascorbic acid from extracellular medium contributes to the intracellular antioxidant capacity, as evaluated by 2',7'-dihydrodichlorofluorescein staining. Consequently, cells became more resistant to free radical generation and cell death induced by UV-B irradiation.
Assuntos
Ácido Ascórbico/metabolismo , Antioxidantes/metabolismo , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Ácido Ascórbico/análogos & derivados , Ácido Ascórbico/farmacologia , Divisão Celular/efeitos dos fármacos , Linhagem Celular , Radicais Livres/metabolismo , Humanos , Queratinócitos/efeitos dos fármacos , Queratinócitos/metabolismo , Queratinócitos/efeitos da radiação , Cinética , NADH NADPH Oxirredutases/metabolismo , Oxirredutases/metabolismo , Frações Subcelulares/metabolismo , Raios UltravioletaRESUMO
Tamoxifen induces apoptosis (programmed cell death) in human erythroleukemia K562 cells. Nitric oxide synthase activity and expression increased in apoptotic cells by 315% and 280%, respectively, compared to controls. The specific inhibitor of nitric oxide synthase, L-NAME, protected K562 cells from tamoxifen-induced apoptosis, whereas the nitric oxide donor, sodium nitroprusside (SNP), potentiated the apoptotic effect of the drug. In addition, 5-lipoxygenase was activated by tamoxifen and the specific enzyme inhibitor, MK886, protected K562 cells against the drug. Conversely, the 5-lipoxygenase product, 5-hydroperoxyeicosatetraenoic acid, enhanced the tamoxifen-induced apoptosis. Finally, tamoxifen altered also membrane properties of K562 cells.
Assuntos
Apoptose/efeitos dos fármacos , Óxido Nítrico Sintase/metabolismo , Tamoxifeno/farmacologia , Ativação Enzimática , Inibidores Enzimáticos/farmacologia , Humanos , Leucemia Eritroblástica Aguda/enzimologia , Leucemia Eritroblástica Aguda/patologia , NG-Nitroarginina Metil Éster/farmacologia , Óxido Nítrico Sintase/antagonistas & inibidores , Nitroprussiato/farmacologia , Células Tumorais CultivadasRESUMO
In animal models, the importance of tumor-derived antiangiogenic factors in controlling metastases has been demonstrated by the growth acceleration of distant metastases after surgical excision of a primary tumor mass. We report the case of an infant who developed rapidly growing cutaneous metastases after surgical resection of a neoplasm of an upper extremity. The tumor was undifferentiated, with some morphological features of primitive neuroectodermal tumor. To test the possibility that the primary tumor was secreting an angiogenic inhibitor, cells from the primary tumor were grown in culture, and the culture medium was tested with an in vitro endothelial cell migration assay and Western blot. The cultured cells secreted sufficiently high levels of an angiogenic inhibitor to overcome the inducing ability of vascular endothelial growth factor and basic fibroblast growth factor. One of the secreted proteins was thrombospondin-1, a potent antiangiogenic glycoprotein. The rapid dissemination of distant metastases after resection of the primary tumor in this case suggests that tumor-derived angiogenic inhibitors are important in maintaining the local net balance of angiogenic mediators controlling the growth of micrometastasis.
Assuntos
Neoplasias Neuroepiteliomatosas/patologia , Neovascularização Patológica , Neuroblastoma/patologia , Tumores Neuroectodérmicos Primitivos Periféricos/patologia , Neoplasias Cutâneas/secundário , Trombospondinas/metabolismo , Células Cultivadas , Endotélio Vascular/metabolismo , Feminino , Humanos , Lactente , Neoplasias Neuroepiteliomatosas/metabolismo , Neuroblastoma/metabolismo , Tumores Neuroectodérmicos Primitivos Periféricos/metabolismo , Sarcoma/metabolismo , Sarcoma/patologia , Neoplasias Cutâneas/patologia , Neoplasias Cutâneas/cirurgiaRESUMO
Acute lymphocytic leukemia (ALL) is a common indication for hematopoietic stem cell transplantation (HSCT) in children. Use of unrelated cord blood (UCB) has become increasingly popular as a stem cell source, given the rapid availability and decreased GVHD potential. Publications describing outcomes of children with leukemia who underwent UCB transplants have compared them to those having received unrelated donor marrow transplants. Results are similar. We compared our outcomes using UCB vs allogeneic-related hematopoietic stem cells in pediatric ALL patients since 1992. A total of 49 patients were analyzed. All patients were either in CR1 with high-risk features (n=21) or in CR2 (n=28) with initial remission less than 36 months. Patients received myeloablation with fractionated total body irradiation, cyclophosphamide, and etoposide and GVHD prophylaxis with cyclosporine and methotrexate. Antithymocyte globulin was added for UCB recipients to address the HLA differences. In all, 23 patients underwent allogeneic -related HSCT and 26 underwent UCB transplantation. Other than increased time to engraftment for UCB recipients, results are equivalent. The 3-year overall survival is 64% and 3-year event-free survival is 60% for both groups. Rates of GVHD and transplant-related mortality are also equivalent. UCB is a reasonable option for children with ALL who are referred for HSCT.
Assuntos
Transplante de Células-Tronco de Sangue do Cordão Umbilical/efeitos adversos , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Leucemia-Linfoma Linfoblástico de Células Precursoras/terapia , Adolescente , Criança , Pré-Escolar , Transplante de Células-Tronco de Sangue do Cordão Umbilical/métodos , Transplante de Células-Tronco de Sangue do Cordão Umbilical/mortalidade , Feminino , Doença Enxerto-Hospedeiro/etiologia , Transplante de Células-Tronco Hematopoéticas/métodos , Transplante de Células-Tronco Hematopoéticas/mortalidade , Teste de Histocompatibilidade , Humanos , Lactente , Masculino , Leucemia-Linfoma Linfoblástico de Células Precursoras/complicações , Leucemia-Linfoma Linfoblástico de Células Precursoras/mortalidade , Estudos Retrospectivos , Risco , Análise de Sobrevida , Doadores de Tecidos , Condicionamento Pré-Transplante/métodos , Transplante Homólogo , Resultado do TratamentoRESUMO
AIM: The aim of this retrospective study was to compare the results of early cholecystectomy and conservative treatment in acute cholecystitis. METHODS: From January 1998 to December 2002, 134 patients were admitted to our Department with the diagnosis of acute cholecystitis. Eighty-nine patients (66%, Group 1) were cured with conservative treatment (i.e. fast, broad-spectrum antibiotics, fluid and analgesic drugs), 45 patients (34%, Group 2) were submitted to early cholecystectomy. The 2 groups were matched for age, sex, laboratory results and echographic findings. RESULTS: The morbidity was 32.5% in Group 1 versus 15.5% in Group 2 (p < 0.05). Mean hospital stay was 18 days in Group 1 as compared to 10.5 days in Group 2 (p < 0.05). At follow-up (12 months) the mean period before starting again a normal working and social life was 57 days in Group 1 and 33 days in Group 2. CONCLUSIONS: The results of this study showed that early cholecystectomy was the gold standard in the treatment of acute cholecystitis, since it reduces morbidity, hospital stay and absence from working and social life in a statistically important way.
Assuntos
Colecistectomia , Colecistite Aguda/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Analgésicos/uso terapêutico , Antibacterianos/uso terapêutico , Colecistite Aguda/diagnóstico , Colecistite Aguda/tratamento farmacológico , Colecistite Aguda/mortalidade , Colecistite Aguda/terapia , Emergências , Feminino , Hidratação , Seguimentos , Humanos , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias , Estudos Retrospectivos , Fatores de TempoRESUMO
The kinetics of growth of eight heterothallic species of the genus Ascobolus was studied in liquid culture media. The results obtained showed variation among the species in the duration of the different phases of the growth cycle. Three groups can be recognized considering the extension of the exponential phase of growth. The stationary phase, which differs in its length, is frequently very short, entering quickly in the phase of death, accompanied by autolysis of the mycelium.
Assuntos
Ascomicetos/crescimento & desenvolvimento , Ascomicetos/classificação , Meios de Cultura , CinéticaRESUMO
Lung cancer incidence over 2005-2010 for 326 Local Authority Districts in England is investigated by ecological regression. Motivated from mis-specification of a Negative Binomial additive model, a semiparametric Negative Binomial M-quantile regression model is introduced. The additive part relates to those univariate or bivariate smoothing components, which are included in the model to capture nonlinearities in the predictor or to account for spatial dependence. All such components are estimated using penalized splines. The results show the capability of the semiparametric Negative Binomial M-quantile regression model to handle data with a strong spatial structure.
Assuntos
Neoplasias Pulmonares/epidemiologia , Análise de Regressão , Inglaterra/epidemiologia , Humanos , IncidênciaRESUMO
AIMS: In this study, we present an innovative therapy using stem cells that were obtained from the peripheral blood of racehorses affected by uninduced superficial digital flexor tendon (SDFT) injuries. MAIN METHODS: Blood-derived stem cells (BDSCs) were generated from the blood samples of three horses in the presence of macrophage colony-stimulating factor (M-CSF). The racehorses received a single autologous BDSC treatment, which resulted in the successful repair of the tendons injuries. KEY FINDINGS: The results demonstrated that the BDSCs injection into the damaged tendon stimulated the regeneration of normal tissue. Furthermore, a relationship may exist between the speed and the quality of new tissue formation and the welfare and management of the treated animals. SIGNIFICANCE: This study demonstrates that stem cell technology offers new tools for tissue repair that in many cases is considered incurable, and provides additional evidence that BDScs injections increase the speed and quality of the regeneration process in different animal tissues.
Assuntos
Doenças dos Cavalos/terapia , Fator Estimulador de Colônias de Macrófagos/farmacologia , Transplante de Células-Tronco/métodos , Traumatismos dos Tendões/terapia , Animais , Feminino , Doenças dos Cavalos/patologia , Cavalos/lesões , Masculino , Regeneração , Transplante de Células-Tronco/veterinária , Traumatismos dos Tendões/veterinária , Fatores de Tempo , Resultado do TratamentoRESUMO
Smoothing over a domain with irregular boundaries or interior gaps and holes is addressed. Consider the problem of estimating mercury in sediment concentrations in the estuarine waters in New Hampshire. A modified version of low-rank thin plate splines (LTPS) is introduced where the geodesic distance is applied to evaluate dissimilarity of any two data observations: loosely speaking, distances between locations are not measured as the crow flies, but as the fish swims. The method is compared with competing smoothing techniques, LTPS, and finite element L-splines.
Assuntos
Interpretação de Imagem Assistida por Computador , Processamento de Imagem Assistida por Computador , Estatísticas não Paramétricas , Animais , Mercúrio/análise , Modelos Biológicos , New Hampshire , Análise de Regressão , Poluentes Químicos da Água/análiseRESUMO
Cajal bodies are small nuclear organelles with a number of nuclear functions. Here we show that FLICE-associated huge protein (FLASH), originally described as a component of the apoptosis signaling pathway, is mainly localized in Cajal bodies and is essential for their structure. Reduction in FLASH expression by short hairpin RNA results in disruption of the normal architecture of the Cajal body and relocalization of its components. Because the function of FLASH in the apoptosis receptor signaling pathway has been strongly questioned, we have now identified a clear function for this protein.
Assuntos
Proteínas Reguladoras de Apoptose/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Corpos Enovelados/metabolismo , Animais , Proteínas Reguladoras de Apoptose/ultraestrutura , Proteínas de Ligação ao Cálcio/ultraestrutura , Corpos Enovelados/patologia , Corpos Enovelados/ultraestrutura , Regulação para Baixo/genética , Células HeLa , Humanos , Camundongos , Sinais de Localização Nuclear/metabolismo , Proteínas Nucleares/metabolismo , Biossíntese de Proteínas/genética , Transporte Proteico , Proteínas Recombinantes de Fusão/metabolismoRESUMO
The oxidative stress could have a dual action on glutathione S-transferase (GST) P1-1 metabolism: transcriptional induction and/or polymerization. The former should represent a form of adaptation to oxidative stress and contribute to protect the cell, the latter one should activate apoptosis via c-Jun N-terminal kinase (JNK). We studied the effect of etoposide on human neuroblastoma cell line SH-SY5Y and on an etoposide-resistant clone to investigate whether a pleiotropic effect of etoposide on the redox status of the cell exists which is able to interfere with apoptosis through the GST P1-1 system. Etoposide treatment was able to induce GST P1-1 polymerization and activation of apoptosis. The data obtained from our etoposide-resistant clone and the possibility to reverse the sensitive phenotype to a resistant one by means of hexyl-glutathione preincubation, seem to suggest that cellular levels of glutathione have a key role in protecting GST P1-1 by oxidation and consequently the cell's decision between life and death.
Assuntos
Apoptose/efeitos dos fármacos , Etoposídeo/farmacologia , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Glutationa Transferase/metabolismo , Glutationa/análogos & derivados , Isoenzimas/metabolismo , Neuroblastoma/enzimologia , Estresse Oxidativo/efeitos dos fármacos , Western Blotting , Células Clonais/efeitos dos fármacos , Células Clonais/metabolismo , Células Clonais/patologia , Resistencia a Medicamentos Antineoplásicos , Glutationa/farmacologia , Glutationa S-Transferase pi , Glutationa Transferase/genética , Humanos , Isoenzimas/genética , Células Tumorais CultivadasRESUMO
Transglutaminases (TGases) are seven enzymes, cross-linking proteins by gamma-glutamil-epsilon-lysine bonds, four of which are expressed in the skin. A new member of the TGase family, TGase 5, has been identified recently, and in the present study we evaluated its role in keratinocyte differentiation in vitro. In addition to the previously described isoforms, full-length TGase 5 and Delta3 (deletion of exon 3), we identified two new splicing variants, Delta11 and Delta3Delta11 (deletion of exons 11 or 3, 11). We expressed full-length TGase 5, Delta3, Delta11, and Delta3Delta11 isoforms in the keratinocyte and baculovirus systems. The results indicate that both full-length TGase 5 and Delta11 are active, whereas Delta3 and Delta3Delta11 have very low activity. Expression studies show that full-length TGase 5 is induced during the early stages of keratinocyte differentiation and is differently regulated in comparison with the other epidermal TGases. Kinetic and in vitro cross-linking experiments indicate that full-length TGase 5 is very efficient in using specific epidermal substrates (loricrin, involucrin, and SPR3). In keratinocyte expression system, TGase 5 isoforms are retained in an intermediate filament-enriched fraction, suggesting its association with insoluble proteins. Indeed, TGase 5 co-localize with vimentin and it is able to cross-link vimentin in vitro.
Assuntos
Isoenzimas/química , Queratinócitos/enzimologia , Proteínas de Membrana/química , Peptídeos , Precursores de Proteínas/química , Proteínas/química , Transglutaminases/química , Baculoviridae/genética , Diferenciação Celular , Centrifugação , Proteínas Ricas em Prolina do Estrato Córneo , Humanos , Queratinócitos/fisiologia , Microscopia Confocal , Domínios Proteicos Ricos em Prolina , Proteínas Recombinantes/química , Solubilidade , Transglutaminases/fisiologiaRESUMO
We investigated the ability of different hydroperoxides generated by lipoxygenase isozymes to induce programmed cell death (PCD) in human cells. Erythroleukemia K562 and neuroblastoma CHP100 cells were used, because they showed high basal activity of lipoxygenase. The hydroperoxides generated by 5-, 12-, or 15-lipoxygenases from linoleate, linolenate, or arachidonate, and the corresponding hydroxides, were able to induce PCD in both cell types, in a concentration- and time-dependent manner. After 24 h, K562 and CHP100 cells showed 2.5- to 3.5-fold more apoptotic bodies than the untreated controls. PCD elicited by lipoxygenase products was independent of intracellular glutathione concentration, and did not require mRNA transcription or protein synthesis. On the other hand, lipoxygenase products evoked an immediate and sustained rise in cytoplasmic calcium (within seconds), followed by mitochondrial uncoupling (within hours). Unlike the hydro(pero)xides, the terminal products of the arachidonate cascade (i.e., leukotrienes, prostaglandins and thromboxane) were not cytotoxic.
Assuntos
Apoptose , Leucemia Eritroblástica Aguda/enzimologia , Leucemia Eritroblástica Aguda/patologia , Lipoxigenase/metabolismo , Neuroblastoma/enzimologia , Neuroblastoma/patologia , Apoptose/efeitos dos fármacos , Ácido Araquidônico/metabolismo , Cálcio/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ativação Enzimática/efeitos dos fármacos , Glutationa/antagonistas & inibidores , Glutationa/metabolismo , Humanos , Isoenzimas/metabolismo , Células K562 , Leucotrienos/farmacologia , Ácido Linoleico/metabolismo , Peróxidos Lipídicos/metabolismo , Peróxidos Lipídicos/farmacologia , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Prostaglandinas/farmacologia , Tromboxano B2/farmacologia , Fatores de Tempo , Células Tumorais Cultivadas , Desacopladores/metabolismo , Desacopladores/farmacologia , Ácido alfa-Linolênico/metabolismoRESUMO
Neuroblastoma is notable for its cellular heterogeneity and unpredictable outcome. Tumors are a variable mixture of primitive malignant neuroblasts, more differentiated ganglionic cells, Schwann and endothelial cells. Although often fatal, neuroblastomas can spontaneously regress, possibly due to favorable autocrine and paracrine interactions among these cells. Here, pigment epithelium-derived factor (PEDF), a potent inhibitor of angiogenesis and inducer of neural differentiation, is shown to be produced by ganglionic cells and Schwann cells, but not by more primitive tumor cells. Although undifferentiated neuroblastoma tumor cell secretions were angiogenic primarily due to vascular endothelial growth factor, secretions of Schwann cells were anti-angiogenic due to PEDF. In addition, PEDF was the major factor responsible for Schwann cell's ability to induce tumor cell differentiation in vitro and recombinant PEDF had the same effect in vitro and in vivo. Both the growth and the survival of Schwann cells were enhanced by PEDF. Thus PEDF may serve as a multifunctional antitumor agent in neuroblastomas, inhibiting angiogenesis while promoting the numbers of Schwann cells and differentiated tumor cells that in turn produce PEDF, suggesting that its clinical administration could stimulate a multifaceted antitumor feedback loop with the potential to limit and possibly regress tumor growth.