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1.
ACS Synth Biol ; 12(8): 2339-2352, 2023 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-37487508

RESUMO

Expression of recombinant proteins in mammalian cell factories relies on synthetic assemblies of genetic parts to optimally control flux through the product biosynthetic pathway. In comparison to other genetic part-types, there is a relative paucity of characterized signal peptide components, particularly for mammalian cell contexts. In this study, we describe a toolkit of signal peptide elements, created using bioinformatics-led and synthetic design approaches, that can be utilized to enhance production of biopharmaceutical proteins in Chinese hamster ovary cell factories. We demonstrate, for the first time in a mammalian cell context, that machine learning can be used to predict how discrete signal peptide elements will perform when utilized to drive endoplasmic reticulum (ER) translocation of specific single chain protein products. For more complex molecular formats, such as multichain monoclonal antibodies, we describe how a combination of in silico and targeted design rule-based in vitro testing can be employed to rapidly identify product-specific signal peptide solutions from minimal screening spaces. The utility of this technology is validated by deriving vector designs that increase product titers ≥1.8×, compared to standard industry systems, for a range of products, including a difficult-to-express monoclonal antibody. The availability of a vastly expanded toolbox of characterized signal peptide parts, combined with streamlined in silico/in vitro testing processes, will permit efficient expression vector re-design to maximize titers of both simple and complex protein products.


Assuntos
Anticorpos Monoclonais , Sinais Direcionadores de Proteínas , Cricetinae , Animais , Cricetulus , Células CHO , Sinais Direcionadores de Proteínas/genética , Proteínas Recombinantes/metabolismo , Anticorpos Monoclonais/metabolismo
2.
Artigo em Inglês | MEDLINE | ID: mdl-36613084

RESUMO

Lung cancer is the world's leading cause of cancer-related deaths. Epidermal growth factor receptor (EGFR) is one of the critical oncogenes and plays a significant role in tumor proliferation and metastasis. Patients with sensitizing mutations in the EGFR gene have better clinical outcomes when treated with tyrosine kinase inhibitors (TKI). This study expands our knowledge of the spectrum of EGFR mutations among lung cancer patients in the Indian scenario. This is a retrospective descriptive study of all newly diagnosed patients with lung cancer in tertiary care hospital in India. All the samples were subjected to real-time PCR (q-PCR) analysis and confirmation of rare novel mutations was done using Sanger sequencing. Clinicopathological characteristics, mutational EGFR status, and location on the exon and metastatic sites were evaluated. An analysis of total 212 samples showed mutations in 38.67% of cases. Among these, five (5.9%) samples had mutations in exon 18, 41 (48.8%) samples had mutations in exon 19, 12 (14.28%) samples had mutations in exon 20, and 26 (30.95%) samples had mutations in exon 21. Eleven (13.41%) were found to be uncommon EGFR mutations. Additionally, six (21.4%) samples that had EGFR mutations were also positive for brain metastasis. Future testing on bigger panels will help to characterize the incidence of genetic mutations and to determine the appropriate targeted treatment choices for NSCLC patients.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Humanos , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Estudos Retrospectivos , Neoplasias Pulmonares/patologia , Mutação , Receptores ErbB/genética , Reação em Cadeia da Polimerase em Tempo Real
3.
J Radiol Prot ; 42(1)2022 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-34715681

RESUMO

For occupational exposures in planned exposure situations International Commission on Radiological Protection (ICRP) publication 118 recommends an equivalent dose limit for the lens of the eye of 20 mSv yr-1averaged over five years with no single year exceeding 50 mSv. This constitutes a reduction from the previous limit of 150 mSv yr-1. The Canadian nuclear regulator, the Canadian Nuclear Safety Commission, responded to the ICRP recommendation by initiating amendments to theRadiation Protection Regulationsthrough a discussion paper which was published for comment by interested stakeholders in 2013. The revised equivalent dose limit of 50 mSv in a one-year dosimetry period for nuclear energy workers came into effect in January 2021. This paper presents the outcome of discussions with Canadian stakeholders in diverse fields of radiological work which focused on the implementation of the reduced occupational equivalent dose limit for the lens of the eye in their respective workplaces. These exchanges highlighted the existing practices for monitoring doses to the lens of the eye and identified current technological gaps. The exchanges also identified that, in many cases, the lens of the eye dose is anticipated to be well within the new dose limit despite some of the gaps in technology. The paper also presents the monitoring and eye-lens dose assessment solutions that are available based on different methods for eye-lens monitoring; presented together with criteria for their use.


Assuntos
Cristalino , Exposição Ocupacional , Proteção Radiológica , Canadá , Humanos , Doses de Radiação , Radiometria
4.
Biotechnol Bioeng ; 118(6): 2326-2337, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33675232

RESUMO

The manufacture of bispecific antibodies by Chinese hamster ovary (CHO) cells is often hindered by lower product yields compared to monoclonal antibodies. Recently, reactive oxygen species have been shown to negatively impact antibody production. By contrast, strategies to boost cellular antioxidant capacity appear to be beneficial for recombinant protein expression. With this in mind, we generated a novel hydrogen peroxide evolved host using directed host cell evolution. Here we demonstrate that this host has heritable resistance to hydrogen peroxide over many generations, displays enhanced antioxidant capacity through the upregulation of several, diverse antioxidant defense genes such as those involved in glutathione synthesis and turnover, and has improved glutathione content. Additionally, we show that this host has significantly improved transfection recovery times, improved growth and viability properties in a fed-batch production process, and elevated expression of two industrially relevant difficult to express bispecific antibodies compared to unevolved CHO control host cells. These findings demonstrate that host cell evolution represents a powerful methodology for improving specific host cell characteristics that can positively impact the expression of difficult to express biotherapeutics.


Assuntos
Anticorpos Biespecíficos/biossíntese , Células CHO , Peróxido de Hidrogênio , Animais , Células CHO/classificação , Cricetulus , Estresse Oxidativo , Proteínas Recombinantes/biossíntese , Transfecção
5.
Support Care Cancer ; 29(8): 4705-4709, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33515104

RESUMO

Immune checkpoint inhibitors, such as pembrolizumab and nivolumab, act by inhibiting programmed death-1 and activating the T cells against cancer. An imbalance in this immune response, however, could lead to immune-related adverse events (irAEs) involving multiple organs like rash, fatigue, hypo and hyperthyroidism, pneumonitis, hepatitis, and colitis, among others. Oral irAEs are not uncommon among immune checkpoint inhibitors which include xerostomia, dysgeusia, and lichenoid reactions; however, oral mucositis is rarely seen or reported in patients receiving PD-1 inhibitors. We present 3 cases of this rare complication in varying grades of severity. The patients were managed with steroids, either topical or systemic, depending on the severity of the lesions with either postponement or withholding therapy due to toxicity. Through this article, we hope to bring to light this overlooked and underdiagnosed oral adverse event associated with the use of immunotherapy and various treatment options for its management.


Assuntos
Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/complicações , Imunoterapia/efeitos adversos , Neoplasias/complicações , Estomatite/complicações , Idoso , Feminino , Humanos , Masculino , Neoplasias/terapia
6.
Antioxid Redox Signal ; 30(7): 972-991, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-28661184

RESUMO

SIGNIFICANCE: Sulfur-containing amino acids are integral to the molecular mechanisms that underlie many aspects of cellular function and homeostasis, facilitated by reversible changes in the oxidation states of sulfur atoms. Sulfur-containing amino acids are metabolically linked by interacting pathways that impact the one-carbon metabolic cycle and generation of methyl groups, the folate cycle, and maintenance of the major cellular redox buffer; glutathione. Dysregulation of these pathways is associated with diverse pathologies, notably of the cardiovascular (CV) system, which are typically characterized by inappropriate plasma levels of sulfur-containing amino acids. Recent Advances: Perhaps not surprisingly, the cellular redox state has emerged as a major regulator of many enzymatic processes within these metabolic cycles. The metabolism of cysteine can also result in the production of hydrogen sulfide (H2S), a signaling molecule whose activity is potentially linked to intracellular levels of both reactive oxygen species (ROS) and molecular oxygen. CRITICAL ISSUES: In most cases, the endogenous physiological sources of ROS that might mediate the interlinked metabolic pathways of sulfur-containing biomolecules remain unknown. However, the family of NADPH oxidases, and Nox4 in particular, is emerging as a likely candidate. FUTURE DIRECTIONS: This review focuses on the current knowledge of key aspects of sulfur metabolism, which are regulated by redox-based chemical reactions, and the likely intracellular oxidant sources that might mediate this regulation. This knowledge will be important to guide future targeted therapeutic interventions in diverse CV disorders.


Assuntos
Aminoácidos/metabolismo , Doenças Cardiovasculares/metabolismo , Enxofre/metabolismo , Animais , Humanos , Sulfeto de Hidrogênio/metabolismo , Redes e Vias Metabólicas , Oxirredução
7.
Indian J Cancer ; 55(2): 170-175, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30604731

RESUMO

INTRODUCTION: Stereotactic body radiotherapy (SBRT) has emerged as an important modality in malignant lung tumor treatment both in early localized primary and oligometastatic setting. This study aims to present the results of lung SBRT both in terms of dosimetry and clinical outcome. MATERIALS AND METHODS: Twenty-seven patients were assessed from 2012 to 2016. Both the primary and oligometastatic lung tumors were evaluated. Respiratory motion management was done employing ANZAI (Siemens, Germany) based four-dimensional computed tomography (CT). Commonly used fractionations were 60 Gy/5 fractions for peripheral tumors and 48 Gy/6 fractions for central tumors. Radiation Therapy Oncology Group toxicity criteria were used for toxicity and whole-body positron emission tomography-CT scan was done at follow-up for response evaluation. RESULTS: Twenty-seven patients were evaluated, 18 (66.7%) patients had a primary, and 9 (33.3%) patients had metastatic lung tumors. The male-to-female ratio for the entire cohort was 2:1. The median age at diagnosis was 65.8 years. Mean planning target volume (PTV) D2cc was 54.9 ± 9.04 Gy and mean internal target volume diameter was 3.0 ± 1.07 cm. Mean V20 Gy, V10 Gy, and V5 Gy of (lungs total-PTV) and (Lung ipsilateral - PTV) were 5.4 ± 4% and 10.9 ± 7.9%, 11.7 ± 5.8% and 24.2 ± 14.0%, and 22.05 ± 12.4% and 33.2 ± 15.3%, respectively. In total 21 (84%) patients and 4 patients (16%) showed a complete and partial response, respectively. One (3%) patient developed Gr 3 radiation pneumonitis. One year local control was in 18 (81%) patients whereas 4 (14%) patients progressed and three patients did not report. A higher prescribed dose significantly correlated with 1 year tumor control (P = 0.036). CONCLUSION: This study infers the feasibility and a favorable outcome for lung cancer amenable to SBRT in addition to being one of the largest clinical experiences for lung stereotactic treatment in our country.


Assuntos
Neoplasias Pulmonares/radioterapia , Radiometria/métodos , Radiocirurgia/métodos , Idoso , Feminino , Humanos , Neoplasias Pulmonares/patologia , Masculino , Resultado do Tratamento
8.
Nucleic Acids Res ; 46(3): 1210-1226, 2018 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-29186571

RESUMO

Graded levels of molecular oxygen (O2) exist within developing mammalian embryos and can differentially regulate cellular specification pathways. During differentiation, cells acquire distinct epigenetic landscapes, which determine their function, however the mechanisms which regulate this are poorly understood. The demethylation of 5-methylcytosine (5mC) is achieved via successive oxidation reactions catalysed by the Ten-Eleven-Translocation (Tet) enzymes, yielding the 5-hydroxymethylcytosine (5hmC) intermediate. These require O2 as a co-factor, and hence may link epigenetic processes directly to O2 gradients during development. We demonstrate that the activities of Tet enzymes display distinct patterns of [O2]-dependency, and that Tet1 activity, specifically, is subject to differential regulation within a range of O2 which is physiologically relevant in embryogenesis. Further, differentiating embryonic stem cells displayed a transient burst of 5hmC, which was both dependent upon Tet1 and inhibited by low (1%) [O2]. A GC-rich promoter region within the Tet3 locus was identified as a significant target of this 5mC-hydroxylation. Further, this region was shown to associate with Tet1, and display the histone epigenetic marks, H3K4me3 and H3K27me3, which are characteristic of a bivalent, developmentally 'poised' promoter. We conclude that Tet1 activity, determined by [O2] may play a critical role in regulating cellular differentiation and fate in embryogenesis.


Assuntos
Dioxigenases/genética , Epigênese Genética , Regulação da Expressão Gênica no Desenvolvimento , Oxigenases de Função Mista/genética , Células-Tronco Embrionárias Murinas/efeitos dos fármacos , Oxigênio/farmacologia , Proteínas Proto-Oncogênicas/genética , 5-Metilcitosina/análogos & derivados , 5-Metilcitosina/metabolismo , Aminoácidos Dicarboxílicos/farmacologia , Animais , Diferenciação Celular/efeitos dos fármacos , Hipóxia Celular , Linhagem Celular , Desmetilação , Dioxigenases/metabolismo , Corpos Embrioides/citologia , Corpos Embrioides/metabolismo , Células HEK293 , Histonas/genética , Histonas/metabolismo , Humanos , Hidroxilação , Camundongos , Oxigenases de Função Mista/metabolismo , Modelos Biológicos , Células-Tronco Embrionárias Murinas/citologia , Células-Tronco Embrionárias Murinas/metabolismo , Oxigênio/metabolismo , Regiões Promotoras Genéticas , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteínas Proto-Oncogênicas/metabolismo
9.
Free Radic Biol Med ; 108: 500-516, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28433660

RESUMO

Reactive oxygen species have emerged as key participants in a broad range of physiological and pathophysiological processes, not least within the vascular system. Diverse cellular functions which have been attributed to some of these pro-oxidants within the vasculature include the regulation of blood pressure, neovascularisation and vascular inflammation. We here highlight the emerging roles of the enzymatically-generated reaction oxygen species, O2- and H2O2, in the regulation of the functions of the gaseous signalling molecules: nitric oxide (NO), carbon monoxide (CO), and hydrogen sulphide (H2S). These gasotransmitters are produced on demand from distinct enzymatic sources and in recent years it has become apparent that they are capable of mediating a number of homeostatic processes within the cardiovascular system including enhanced vasodilation, angiogenesis, wound healing and improved cardiac function following myocardial infarction. In common with O2- and/or H2O2 they signal by altering the functions of target proteins, either by the covalent modification of thiol groups or by direct binding to metal centres within metalloproteins, most notably haem proteins. The regulation of the enzymes which generate NO, CO and H2S have been shown to be influenced at both the transcriptional and post-translational levels by redox-dependent mechanisms, while the activity and bioavailability of the gasotransmitters themselves are also subject to oxidative modification. Within vascular cells, the family of nicotinamide adenine dinucleotide phosphate oxidases (NAPDH oxidases/Noxs) have emerged as functionally significant sources of regulated O2- and H2O2 production and accordingly, direct associations between Nox-generated oxidants and the functions of specific gasotransmitters are beginning to be identified. This review focuses on the current knowledge of the redox-dependent mechanisms which regulate the generation and activity of these gases, with particular reference to their roles in angiogenesis.


Assuntos
Sistema Cardiovascular/metabolismo , Gasotransmissores/metabolismo , Neovascularização Fisiológica , Animais , Regulação da Expressão Gênica , Humanos , Oxirredução , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , Fator A de Crescimento do Endotélio Vascular/metabolismo
10.
J Cancer Res Ther ; 12(2): 515-9, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27461602

RESUMO

Superior vena cava syndrome is referred to as a constellation of symptoms and signs caused by obstruction of superior vena cava. It can occur due to both benign and malignant causes with the latter being the predominant. There is a paradigm shift in the approach to manage this condition. It is no longer considered a medical emergency and histological diagnosis is necessary before treatment. This article reviews the causes, symptoms, pathophysiology, and overall management policy which have changed over decades.


Assuntos
Síndrome da Veia Cava Superior/diagnóstico , Síndrome da Veia Cava Superior/etiologia , Síndrome da Veia Cava Superior/radioterapia , Humanos , Gradação de Tumores , Neoplasias/complicações , Neoplasias/diagnóstico , Neoplasias/terapia , Radio-Oncologistas , Radioterapia (Especialidade)
11.
J Biol Chem ; 291(4): 1774-1788, 2016 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-26620565

RESUMO

The gasotransmitter, hydrogen sulfide (H2S) is recognized as an important mediator of endothelial cell homeostasis and function that impacts upon vascular tone and blood pressure. Cystathionine-γ-lyase (CSE) is the predominant endothelial generator of H2S, and recent evidence suggests that its transcriptional expression is regulated by the reactive oxygen species, H2O2. However, the cellular source of H2O2 and the redox-dependent molecular signaling pathway that modulates this is not known. We aimed to investigate the role of Nox4, an endothelial generator of H2O2, in the regulation of CSE in endothelial cells. Both gain- and loss-of-function experiments in human endothelial cells in vitro demonstrated Nox4 to be a positive regulator of CSE transcription and protein expression. We demonstrate that this is dependent upon a heme-regulated inhibitor kinase/eIF2α/activating transcription factor 4 (ATF4) signaling module. ATF4 was further demonstrated to bind directly to cis-regulatory sequences within the first intron of CSE to activate transcription. Furthermore, CSE expression was also increased in cardiac microvascular endothelial cells, isolated from endothelial-specific Nox4 transgenic mice, compared with wild-type littermate controls. Using wire myography we demonstrate that endothelial-specific Nox4 transgenic mice exhibit a hypo-contractile phenotype in response to phenylephrine that was abolished when vessels were incubated with a CSE inhibitor, propargylglycine. We, therefore, conclude that Nox4 is a positive transcriptional regulator of CSE in endothelial cells and propose that it may in turn contribute to the regulation of vascular tone via the modulation of H2S production.


Assuntos
Cistationina gama-Liase/genética , Regulação Enzimológica da Expressão Gênica , Células Endoteliais da Veia Umbilical Humana/enzimologia , NADPH Oxidases/metabolismo , Transcrição Gênica , Fator 4 Ativador da Transcrição/genética , Fator 4 Ativador da Transcrição/metabolismo , Animais , Cistationina gama-Liase/metabolismo , Regulação da Expressão Gênica , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , NADPH Oxidase 4 , NADPH Oxidases/genética , Transdução de Sinais
12.
Free Radic Biol Med ; 89: 918-30, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26472193

RESUMO

Glutathione is the major intracellular redox buffer in the liver and is critical for hepatic detoxification of xenobiotics and other environmental toxins. Hepatic glutathione is also a major systemic store for other organs and thus impacts on pathologies such as Alzheimer's disease, Sickle Cell Anaemia and chronic diseases associated with aging. Glutathione levels are determined in part by the availability of cysteine, generated from homocysteine through the transsulfuration pathway. The partitioning of homocysteine between remethylation and transsulfuration pathways is known to be subject to redox-dependent regulation, but the underlying mechanisms are not known. An association between plasma Hcy and a single nucleotide polymorphism within the NADPH oxidase 4 locus led us to investigate the involvement of this reactive oxygen species- generating enzyme in homocysteine metabolism. Here we demonstrate that NADPH oxidase 4 ablation in mice results in increased flux of homocysteine through the betaine-dependent remethylation pathway to methionine, catalysed by betaine-homocysteine-methyltransferase within the liver. As a consequence NADPH oxidase 4-null mice display significantly lowered plasma homocysteine and the flux of homocysteine through the transsulfuration pathway is reduced, resulting in lower hepatic cysteine and glutathione levels. Mice deficient in NADPH oxidase 4 had markedly increased susceptibility to acetaminophen-induced hepatic injury which could be corrected by administration of N-acetyl cysteine. We thus conclude that under physiological conditions, NADPH oxidase 4-derived reactive oxygen species is a regulator of the partitioning of the metabolic flux of homocysteine, which impacts upon hepatic cysteine and glutathione levels and thereby upon defence against environmental toxins.


Assuntos
Acetaminofen/toxicidade , Analgésicos não Narcóticos/toxicidade , Homocisteína/metabolismo , Hepatopatias/prevenção & controle , Fígado/metabolismo , NADPH Oxidases/fisiologia , Animais , Betaína/metabolismo , Western Blotting , Células Cultivadas , Cisteína/metabolismo , Feminino , Glutationa/metabolismo , Células Hep G2 , Humanos , Técnicas Imunoenzimáticas , Fígado/efeitos dos fármacos , Fígado/patologia , Hepatopatias/etiologia , Metionina/metabolismo , Camundongos , Camundongos Knockout , NADPH Oxidase 4 , Espécies Reativas de Oxigênio/metabolismo , S-Adenosilmetionina/metabolismo
13.
J BUON ; 20(3): 782-90, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26214631

RESUMO

PURPOSE: Circulating tumor cells (CTCs) are rare and difficult to isolate, and require selecting minimal but appropriate markers. The aim of this study was to identify markers in the primary non small cell lung cancer (NSCLC) tissue to guide isolation of CTCs from the peripheral blood of patients with lung cancer. METHODS: The expression of CK-19, EGFR and MUC-1 was evaluated by RT-PCR in the NSCLC tumor and paired adjacent normal tissues from 27 patients. The normal cytology, and the neoplastic and fibrotic pathology of the tissue were analyzed by histochemistry. The expression of the markers was analyzed in relation to the stage and grade of disease. RESULTS: Expression analysis showed that 42% of the tumors were positive for CK-19, whereas 85% for both EGFR and MUC-1. Ninety two percent of the tumors expressed any one marker. All (100%) adjacent normal tissues were CK-19 negative, 52% EGFR negative and 44% MUC-1 negative. CK-19 expression was specific to the tumor tissue but it was expressed by only 42% of them, manifesting a need for at least three markers to guide the detection of CTCs isolated from the peripheral blood of NSCLC patients. Histopathology demonstrated that 58% were adenocarcinomas, 35% squamous cell carcinomas and 7% had mixed pathology. CONCLUSIONS: This data serves as a prelude and emphasizes the importance of selecting markers expressed in the primary tumor tissue to facilitate and enable enumeration of CTCs.


Assuntos
Adenocarcinoma/sangue , Biomarcadores Tumorais/sangue , Carcinoma Pulmonar de Células não Pequenas/sangue , Carcinoma de Células Escamosas/sangue , Neoplasias Pulmonares/sangue , Células Neoplásicas Circulantes/química , Adenocarcinoma/química , Adenocarcinoma/genética , Adenocarcinoma/patologia , Adenocarcinoma de Pulmão , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/genética , Carcinoma Pulmonar de Células não Pequenas/química , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Carcinoma de Células Escamosas/química , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patologia , Linhagem Celular Tumoral , Receptores ErbB/sangue , Feminino , Humanos , Queratina-19/sangue , Neoplasias Pulmonares/química , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade , Mucina-1/sangue , Gradação de Tumores , Estadiamento de Neoplasias , Valor Preditivo dos Testes , Reação em Cadeia da Polimerase em Tempo Real
14.
J Mol Cell Cardiol ; 79: 54-68, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25450615

RESUMO

Adult mammalian cardiomyocytes have a very limited capacity to proliferate, and consequently the loss of cells after cardiac stress promotes heart failure. Recent evidence suggests that administration of hydrogen peroxide (H2O2), can regulate redox-dependent signalling pathway(s) to promote cardiomyocyte proliferation in vitro, but the potential relevance of such a pathway in vivo has not been tested. We have generated a transgenic (Tg) mouse model in which the H2O2-generating enzyme, NADPH oxidase 4 (Nox4), is overexpressed within the postnatal cardiomyocytes, and observed that the hearts of 1-3week old Tg mice pups are larger in comparison to wild type (Wt) littermate controls. We demonstrate that the cardiomyocytes of Tg mouse pups have increased cell cycling capacity in vivo as determined by incorporation of 5-bromo-2'-deoxyuridine. Further, microarray analyses of the transcriptome of these Tg mouse hearts suggested that the expression of cyclin D2 is significantly increased. We investigated the molecular mechanisms which underlie this more proliferative phenotype in isolated neonatal rat cardiomyocytes (NRCs) in vitro, and demonstrate that Nox4 overexpression mediates an H2O2-dependent activation of the ERK1/2 signalling pathway, which in turn phosphorylates and activates the transcription factor c-myc. This results in a significant increase in cyclin D2 expression, which we show to be mediated, at least in part, by cis-acting c-myc binding sites within the proximal cyclin D2 promoter. Overexpression of Nox4 in NRCs results in an increase in their proliferative capacity that is ablated by the silencing of cyclin D2. We further demonstrate activation of the ERK1/2 signalling pathway, increased phosphorylation of c-myc and significantly increased expression of cyclin D2 protein in the Nox4 Tg hearts. We suggest that this pathway acts to maintain the proliferative capacity of cardiomyocytes in Nox4 Tg pups in vivo and so delays their exit from the cell cycle after birth.


Assuntos
Ciclo Celular , Ciclina D2/genética , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Miócitos Cardíacos/citologia , Miócitos Cardíacos/enzimologia , Proteínas Proto-Oncogênicas c-myc/metabolismo , Transcrição Gênica , Animais , Animais Recém-Nascidos , Sequência de Bases , Sítios de Ligação/genética , Cardiomegalia/genética , Cardiomegalia/patologia , Ciclo Celular/genética , Proliferação de Células , Sequência Conservada/genética , Ciclina D2/metabolismo , Camundongos Transgênicos , Dados de Sequência Molecular , Miocárdio/metabolismo , Miocárdio/patologia , NADPH Oxidase 4 , NADPH Oxidases/metabolismo , Oxirredução , Fosforilação , Regiões Promotoras Genéticas/genética , Ratos , Espécies Reativas de Oxigênio/metabolismo , Regulação para Cima/genética
15.
Arch Surg ; 147(8): 747-51, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22911072

RESUMO

HYPOTHESIS: Controversy exists over the need for prolonged nasogastric decompression after esophagectomy. We hypothesized that early removal of the nasogastric tube would not adversely affect major pulmonary complications and anastomotic leak rates. DESIGN: Single-center, parallel-group, open-label, randomized (1:1) trial. SETTING: A tertiary referral cancer center with high esophagectomy volume. PATIENTS: One hundred fifty patients undergoing esophagectomy with gastric tube reconstruction. INTERVENTIONS: Either conventional nasogastric decompression for 6 to 10 days (75 patients) or early removal (48 hours) of nasogastric tube (75 patients) with stratification for pyloric drainage and anastomotic technique. MAIN OUTCOME MEASURES: The primary (composite) end point was the occurrence of major pulmonary complications and anastomotic leaks. Secondary end points were the need for nasogastric tube reinsertion and patient discomfort scores. Analysis was performed on an intent-to-treat basis. RESULTS: No significant differences were seen in the occurrence of the composite primary end point of major pulmonary and anastomotic complications between the delayed (14 of 75 patients [18.7%]) and early (16 of 75 patients [21.3%]) removal groups, respectively (P = .84). Nasogastric tube reinsertion was required more often (23 of 75 patients [30.7%] vs 7 of 75 patients [9.3%]) in the early group (P = .001). Mean patient discomfort scores were significantly higher in the delayed (+1.3; 95% CI, 0.4-2.2; P = .006) than in the early removal group. Significantly more patients in the delayed removal group (26 of 75 patients [34.7%] vs 10 of 75 patients [13.3%] in the early removal group; P = .002) identified the nasogastric tube as the tube causing the most discomfort. CONCLUSIONS: Early removal of nasogastric tubes does not increase pulmonary or anastomotic complications after esophagectomy. Patient discomfort can be significantly reduced by early removal of the nasogastric tube. TRIAL REGISTRATION: Clinical Trials Registry of India Identifier: CTRI/2010/091/003023.


Assuntos
Descompressão Cirúrgica/métodos , Esofagectomia/efeitos adversos , Intubação Gastrointestinal , Adulto , Idoso , Remoção de Dispositivo , Feminino , Humanos , Análise de Intenção de Tratamento , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/prevenção & controle , Fatores de Tempo
16.
J Cell Mol Med ; 16(3): 531-44, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21507199

RESUMO

Immune dysfunction is hallmark of patients with non-small cell lung carcinoma (NSCLC). The molecular mechanism involved in COX-2- and PGE2-mediated production of immunosuppressive cytokine IL-10 is not well-understood. Our study addresses the involvement of T cell downstream signalling intermediates, cytokines (IL-10 and IFN-γ) and their transcription factors (T-bet and GATA-3) in COX-2-mediated regulation of lymphocyte functions in NSCLC patients. In comparison to healthy individual, a marked decrease in lymphocyte proliferation to anti-CD3 MAb was observed in NSCLC patients by thymidine incorporation assay. Using flow cytometry, decrease in intracellular calcium release with increase in reactive oxygen species was observed in lymphocytes of NSCLC patients. These patients showed increased IL-10 and PGE2 with reduced IFN-γ production by ELISA. Results demonstrated defect in regulation of transcription factors T-bet and GATA-3 as analysed by Western blotting (WB), immunoprecipitation and EMSA. Overexpression of p-p38, p-ERK and COX-2 were observed with diminished p-JNK by WB. IL-10/IFN-γ levels were found to be differentially regulated via p38 and ERK mitogen-activated protein kinase (MAPK) pathways in cooperation with COX-2. Inhibition of these pathways using selective inhibitors lead to increased lymphocyte proliferative response to anti-CD3 MAb and IFN-γ production with decrease in IL-10 production. Studies showed involvement of ERK, p38 and COX-2 pathways in high IL-10 production, driven by lung tumour derived PGE2. The selective COX-2 inhibitor rofecoxib showed ability to alter the cytokine balance by affecting regulation of T-bet and GATA-3 transcription factors.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/imunologia , Ciclo-Oxigenase 2/fisiologia , MAP Quinases Reguladas por Sinal Extracelular/fisiologia , Interleucina-10/biossíntese , Lactonas/farmacologia , Neoplasias Pulmonares/imunologia , Sulfonas/farmacologia , Proteínas Quinases p38 Ativadas por Mitógeno/fisiologia , Anticorpos Monoclonais/farmacologia , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/genética , Proliferação de Células/efeitos dos fármacos , Ciclo-Oxigenase 2/genética , Inibidores de Ciclo-Oxigenase 2/farmacologia , Dinoprostona/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/genética , Fator de Transcrição GATA3/genética , Fator de Transcrição GATA3/imunologia , Regulação Neoplásica da Expressão Gênica , Humanos , Interferon gama/biossíntese , Interferon gama/imunologia , Interleucina-10/imunologia , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Linfócitos/efeitos dos fármacos , Linfócitos/imunologia , Cultura Primária de Células , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteínas com Domínio T/genética , Proteínas com Domínio T/imunologia , Proteínas Quinases p38 Ativadas por Mitógeno/genética
17.
Ann Thorac Cardiovasc Surg ; 17(4): 400-3, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21881330

RESUMO

A 43-year-old woman presented to us with progressive breathlessness, dry cough and weight loss. A chest radiograph showed homogeneous opacification of the entire left hemithorax. A contrast enhanced computed tomography (CECT) scan of the thorax showed a large intrathoracic mass occupying almost the entire left hemithorax and appeared grossly inoperable. A transcutaneous CT guided tru-cut biopsy revealed a solitary fibrous tumour. We reviewed the CT scans based on the biopsy report, and, in retrospect, the mediastinal vessels seemed more stretched and pushed by the tumor rather than directly infiltrated by it. We performed an exploratory thoracotomy and to our surprise, were able to dissect the mass quite easily off the mediastinum. She had an uneventful postoperative recovery, and the final histopathology confirmed a solitary fibrous tumor. We report this case to emphasize that a cursory clinico-radiological interpretation can dissuade surgical intervention in these patients.


Assuntos
Neoplasias Pleurais/diagnóstico , Tumor Fibroso Solitário Pleural/diagnóstico , Adulto , Biópsia , Feminino , Humanos , Imuno-Histoquímica , Neoplasias Pleurais/complicações , Neoplasias Pleurais/cirurgia , Tomografia por Emissão de Pósitrons , Tumor Fibroso Solitário Pleural/complicações , Tumor Fibroso Solitário Pleural/cirurgia , Toracotomia , Tomografia Computadorizada por Raios X , Resultado do Tratamento
18.
Int J Radiat Oncol Biol Phys ; 79(1): 202-7, 2011 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-20399028

RESUMO

PURPOSE: To evaluate the prognostic factors and treatment outcome of patients with Askin-Rosai tumor of the chest wall treated at a single institution. METHODS AND MATERIALS: Treatment comprised multiagent chemotherapy and local therapy, which was either in the form of surgery alone, radical external-beam radiotherapy (EBRT) alone, or a combination of surgery and EBRT. Thirty-two patients (40%) were treated with all three modalities, 21 (27%) received chemotherapy and radical EBRT, and 19 (24%) underwent chemotherapy followed by surgery only. RESULTS: One hundred four consecutive patients aged 3-60 years were treated at the Tata Memorial Hospital from January 1995 to October 2003. Most (70%) were male (male/female ratio, 2.3:1). Asymptomatic swelling (43%) was the most common presenting symptom, and 25% of patients presented with distant metastasis. After a median follow-up of 28 months, local control, disease-free survival, and overall survival rates were 67%, 36%, and 45%, respectively. Median time to relapse was 25 months, and the median survival was 76 months. Multivariate analysis revealed age ≥18 years, poor response to induction chemotherapy, and presence of pleural effusion as indicators of inferior survival. Fifty-six percent of patients with metastatic disease at presentation died within 1 month of diagnosis, with 6-month and 5-year actuarial survival of 14% and 4%, respectively. CONCLUSION: Primary tumor size, pleural effusion, response to chemotherapy, and optimal radiotherapy were important prognostic factors influencing outcome. The combination of neoadjuvant chemotherapy, surgery, and radiotherapy resulted in optimal outcome.


Assuntos
Tumores Neuroectodérmicos Primitivos Periféricos/terapia , Neoplasias Torácicas/terapia , Parede Torácica , Adolescente , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Criança , Pré-Escolar , Radioisótopos de Cobalto/uso terapêutico , Terapia Combinada/métodos , Terapia Combinada/mortalidade , Intervalo Livre de Doença , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Tumores Neuroectodérmicos Primitivos Periféricos/mortalidade , Tumores Neuroectodérmicos Primitivos Periféricos/patologia , Tumores Neuroectodérmicos Primitivos Periféricos/secundário , Derrame Pleural/mortalidade , Prognóstico , Dosagem Radioterapêutica , Indução de Remissão , Taxa de Sobrevida , Neoplasias Torácicas/mortalidade , Neoplasias Torácicas/patologia , Carga Tumoral , Adulto Jovem
19.
Radiat Prot Dosimetry ; 141(1): 1-9, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20447939

RESUMO

Gypsum wallboard (drywall) represents an attractive target for retrospective dosimetry by optically stimulated luminescence (OSL) in the event of a radiological accident or malicious use of nuclear material. In this study, wallboard is shown to display a radiation-induced luminescence signal (RIS) as well as a natural background signal (NS), which is comparable in intensity to the RIS. Excitation and emission spectra show that maximum luminescence intensity is obtained for stimulation with blue light-emitting diodes (470 nm) and for detection in the ultraviolet region (290-370 nm). It is necessary to decrease the optical stimulation power dramatically in order to adequately separate the RIS from the interfering background signal. The necessary protocols are developed for accurately measuring the absorbed dose as low as 500 mGy and demonstrate that the RIS decays logarithmically with storage time, with complete erasure expected within 1-4 d.


Assuntos
Sulfato de Cálcio/efeitos da radiação , Materiais de Construção , Luz , Dosimetria Termoluminescente/métodos , Relação Dose-Resposta à Radiação , Luminescência
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