Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
BMJ Open ; 13(7): e068339, 2023 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-37407044

RESUMO

INTRODUCTION: Optimal delivery and organisation of care is critical for surgical outcomes and healthcare systems efficiency. Anaesthesia volumes have been recently associated with improved postoperative recovery outcomes; however, the mechanism is unclear. Understanding the individual processes of care (interventions received by the patient) is important to design effective systems that leverage the volume-outcome association to improve patient care. The primary objective of this scoping review is to systematically map the evidence regarding intraoperative processes of care for upper gastrointestinal cancer surgery. We aim to synthesise the quantity, type, and scope of studies on intraoperative processes of care in adults who undergo major upper gastrointestinal cancer surgeries (oesophagectomy, hepatectomy, pancreaticoduodenectomy, and gastrectomy) to better understand the volume-outcome relationship for anaesthesiology care. METHODS AND ANALYSIS: This scoping review will follow the Arksey and O'Malley framework and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension framework for scoping reviews. We will systematically search MEDLINE, Embase and Cochrane databases for original research articles published after 2010 examining postoperative outcomes in adult patients undergoing either: oesophagectomy, hepatectomy, pancreaticoduodenectomy, or gastrectomy, which report at least one intraoperative processes of care (intervention or framework) applied by anaesthesia or surgery. The data from included studies will be extracted, charted, and summarised both quantitatively and qualitatively through descriptive statistics and narrative synthesis. ETHICS AND DISSEMINATION: No ethics approval is required for this scoping review. Results will be disseminated through publication targeted at relevant stakeholders in anaesthesiology and cancer surgery. TRIAL REGISTRATION NUMBER: 10.17605/OSF.IO/392UG; https://archive.org/details/osf-registrations-392ug-v1.


Assuntos
Anestesiologia , Neoplasias Gastrointestinais , Adulto , Humanos , Anastomose Cirúrgica , Neoplasias Gastrointestinais/cirurgia , Hepatectomia , Oncologia , Projetos de Pesquisa , Literatura de Revisão como Assunto
2.
Nat Commun ; 13(1): 3750, 2022 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-35768438

RESUMO

Multiple myeloma is the second most common hematological malignancy. Despite significant advances in treatment, relapse is common and carries a poor prognosis. Thus, it is critical to elucidate the genetic factors contributing to disease progression and drug resistance. Here, we carry out integrative clinical sequencing of 511 relapsed, refractory multiple myeloma (RRMM) patients to define the disease's molecular alterations landscape. The NF-κB and RAS/MAPK pathways are more commonly altered than previously reported, with a prevalence of 45-65% each. In the RAS/MAPK pathway, there is a long tail of variants associated with the RASopathies. By comparing our RRMM cases with untreated patients, we identify a diverse set of alterations conferring resistance to three main classes of targeted therapy in 22% of our cohort. Activating mutations in IL6ST are also enriched in RRMM. Taken together, our study serves as a resource for future investigations of RRMM biology and potentially informs clinical management.


Assuntos
Mieloma Múltiplo , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Resistência a Medicamentos , Resistencia a Medicamentos Antineoplásicos/genética , Heterogeneidade Genética , Humanos , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/genética , Mieloma Múltiplo/patologia , Recidiva Local de Neoplasia/tratamento farmacológico , Recidiva Local de Neoplasia/genética , Recidiva Local de Neoplasia/patologia
3.
Cancer Prev Res (Phila) ; 13(7): 569-582, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32409593

RESUMO

Almost all pancreatic ductal adenocarcinomas (PDA) develop following KRAS activation, which triggers epithelial transformation and recruitment of desmoplastic stroma through additional transcriptional and epigenetic regulation, but only a few of these regulatory mechanisms have been described. We profiled dysregulated miRNAs starting with the earliest premalignant pancreatic intraepithelial neoplasias (PanIN) in genetically engineered mutated KRAS and P53 (KPC) mice programmed to recapitulate human PDA tumorigenesis. We identified miR-21 and miR-224 as cell-specific and compartment-specific regulators in PanINs and PDA. miR-21 is overexpressed in tumor epithelial cells of premalignant ducts, while miR-224 is overexpressed in cancer-associated fibroblasts in PDA stroma. Inhibition of miR-21 reverted protumorigenic functionalities to baseline levels. Overexpression of miR-224 induced activated phenotypes in normal fibroblasts. In vivo miR-21 inhibition improved survival in established PDA. Importantly, early systemic miR-21 inhibition completely intercepted premalignant progression. Finally, an evaluation of miR-21 expression in the PDA cohort of The Cancer Genome Atlas identified a correlation between tumor epithelial cell content and miR-21 expression in human tumors providing further rationale for conducting human studies. Thus, miR-21 may be useful for early PanIN detection, and for intercepting developing premalignant pancreatic lesions and other KRAS-driven premalignancies.


Assuntos
Biomarcadores Tumorais/genética , Carcinoma Ductal Pancreático/patologia , Regulação Neoplásica da Expressão Gênica , MicroRNAs/genética , Mutação , Neoplasias Pancreáticas/patologia , Proteínas Proto-Oncogênicas p21(ras)/genética , Animais , Apoptose , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/metabolismo , Proliferação de Células , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Prognóstico , Células Tumorais Cultivadas
4.
Cancer Res ; 79(19): 5102-5112, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31337651

RESUMO

Tumor heterogeneity provides a complex challenge to cancer treatment and is a critical component of therapeutic response, disease recurrence, and patient survival. Single-cell RNA-sequencing (scRNA-seq) technologies have revealed the prevalence of intratumor and intertumor heterogeneity. Computational techniques are essential to quantify the differences in variation of these profiles between distinct cell types, tumor subtypes, and patients to fully characterize intratumor and intertumor molecular heterogeneity. In this study, we adapted our algorithm for pathway dysregulation, Expression Variation Analysis (EVA), to perform multivariate statistical analyses of differential variation of expression in gene sets for scRNA-seq. EVA has high sensitivity and specificity to detect pathways with true differential heterogeneity in simulated data. EVA was applied to several public domain scRNA-seq tumor datasets to quantify the landscape of tumor heterogeneity in several key applications in cancer genomics such as immunogenicity, metastasis, and cancer subtypes. Immune pathway heterogeneity of hematopoietic cell populations in breast tumors corresponded to the amount of diversity present in the T-cell repertoire of each individual. Cells from head and neck squamous cell carcinoma (HNSCC) primary tumors had significantly more heterogeneity across pathways than cells from metastases, consistent with a model of clonal outgrowth. Moreover, there were dramatic differences in pathway dysregulation across HNSCC basal primary tumors. Within the basal primary tumors, there was increased immune dysregulation in individuals with a high proportion of fibroblasts present in the tumor microenvironment. These results demonstrate the broad utility of EVA to quantify intertumor and intratumor heterogeneity from scRNA-seq data without reliance on low-dimensional visualization. SIGNIFICANCE: This study presents a robust statistical algorithm for evaluating gene expression heterogeneity within pathways or gene sets in single-cell RNA-seq data.


Assuntos
Algoritmos , Neoplasias/genética , RNA-Seq/métodos , Análise de Sequência de RNA/métodos , Humanos , Análise de Célula Única/métodos
5.
JCI Insight ; 4(6)2019 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-30895946

RESUMO

BACKGROUND: PD-L1 expression and tumor mutational burden (TMB) have emerged as important biomarkers of response to immune checkpoint inhibitor (ICI) therapy. These biomarkers have each succeeded and failed in predicting responders for different cancer types. We sought to describe the PD-L1 expression landscape across the spectrum of ICI-responsive human cancers, and to determine the relationship between PD-L1 expression, TMB, and response rates to ICIs. METHODS: We assessed 9887 clinical samples for PD-L1 expression and TMB. RESULTS: PD-L1 expression and TMB are not significantly correlated within most cancer subtypes, and they show only a marginal association at the tumor sample level (Pearson's correlation 0.084). Across distinct tumor types, PD-L1 expression and TMB have nonoverlapping effects on the response rate to PD-1/PD-L1 inhibitors and can broadly be used to categorize the immunologic subtypes of cancer. CONCLUSION: Our results indicate that PD-L1 expression and TMB may each inform the use of ICIs, point to different mechanisms by which PD-L1 expression regulates ICI responsiveness, and identify new opportunities for therapeutic development. FUNDING: Funding was provided by Foundation Medicine Inc., the Johns Hopkins Bloomberg-Kimmel Institute for Cancer Immunotherapy, the Viragh Foundation, the National Cancer Institute Specialized Program of Research Excellence (SPORE) in Gastrointestinal Cancers (P50 CA062924), the NIH Center Core Grant (P30 CA006973), the Norman & Ruth Rales Foundation, and the Conquer Cancer Foundation.


Assuntos
Antígeno B7-H1/metabolismo , Biomarcadores Tumorais/metabolismo , Neoplasias/metabolismo , Carga Tumoral/fisiologia , Antígeno B7-H1/genética , Antígeno B7-H1/imunologia , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/imunologia , Bases de Dados Factuais , Humanos , Imunoterapia , Neoplasias/genética , Neoplasias/imunologia , Receptor de Morte Celular Programada 1/metabolismo , Carga Tumoral/genética , Carga Tumoral/imunologia
6.
JCI Insight ; 3(20)2018 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-30333318

RESUMO

Tumor neoantigens arising from somatic mutations in the cancer genome are less likely to be subject to central immune tolerance and are therefore attractive targets for vaccine immunotherapy. We utilized whole-exome sequencing, RNA sequencing (RNASeq), and an in silico immunogenicity prediction algorithm, NetMHC, to generate a neoantigen-targeted vaccine, PancVAX, which was administered together with the STING adjuvant ADU-V16 to mice bearing pancreatic adenocarcinoma (Panc02) cells. PancVAX activated a neoepitope-specific T cell repertoire within the tumor and caused transient tumor regression. When given in combination with two checkpoint modulators, namely anti-PD-1 and agonist OX40 antibodies, PancVAX resulted in enhanced and more durable tumor regression and a survival benefit. The addition of OX40 to vaccine reduced the coexpression of T cell exhaustion markers, Lag3 and PD-1, and resulted in rejection of tumors upon contralateral rechallenge, suggesting the induction of T cell memory. Together, these data provide the framework for testing personalized neoantigen-based combinatorial vaccine strategies in patients with pancreatic and other nonimmunogenic cancers.


Assuntos
Adenocarcinoma/terapia , Antineoplásicos Imunológicos/farmacologia , Vacinas Anticâncer/administração & dosagem , Imunoterapia/métodos , Neoplasias Pancreáticas/terapia , Adenocarcinoma/genética , Adenocarcinoma/imunologia , Adjuvantes Imunológicos/administração & dosagem , Animais , Antígenos de Neoplasias/genética , Antígenos de Neoplasias/imunologia , Antineoplásicos Imunológicos/uso terapêutico , Vacinas Anticâncer/genética , Vacinas Anticâncer/imunologia , Linhagem Celular Tumoral/transplante , Terapia Combinada/métodos , Modelos Animais de Doenças , Epitopos de Linfócito T/genética , Epitopos de Linfócito T/imunologia , Humanos , Imunogenicidade da Vacina , Proteínas de Membrana/imunologia , Camundongos , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/imunologia , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Receptor de Morte Celular Programada 1/imunologia , Receptores OX40/agonistas , Receptores OX40/imunologia , Resultado do Tratamento , Evasão Tumoral/efeitos dos fármacos , Evasão Tumoral/imunologia , Vacinas de Subunidades Antigênicas/administração & dosagem , Vacinas de Subunidades Antigênicas/genética , Vacinas de Subunidades Antigênicas/imunologia
7.
Cancer Immunol Res ; 6(12): 1561-1577, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30341213

RESUMO

Immune-checkpoint inhibition (ICI) has revolutionized treatment in cancers that are naturally immunogenic by enabling infiltration of T cells into the tumor microenvironment (TME) and promoting cytotoxic signaling pathways. Tumors possessing complex immunosuppressive TMEs such as breast and pancreatic cancers present unique therapeutic obstacles as response rates to ICI remain low. Such tumors often recruit myeloid-derived suppressor cells (MDSCs), whose functioning prohibits both T-cell activation and infiltration. We attempted to sensitize these tumors to ICI using epigenetic modulation to target MDSC trafficking and function to foster a less immunosuppressive TME. We showed that combining a histone deacetylase inhibitor, entinostat (ENT), with anti-PD-1, anti-CTLA-4, or both significantly improved tumor-free survival in both the HER2/neu transgenic breast cancer and the Panc02 metastatic pancreatic cancer mouse models. Using flow cytometry, gene-expression profiling, and ex vivo functional assays, we characterized populations of tumor-infiltrating lymphocytes (TILs) and MDSCs, as well as their functional capabilities. We showed that addition of ENT to checkpoint inhibition led to significantly decreased suppression by granulocytic MDSCs in the TME of both tumor types. We also demonstrated an increase in activated granzyme-B-producing CD8+ T effector cells in mice treated with combination therapy. Gene-expression profiling of both MDSCs and TILs identified significant changes in immune-related pathways. In summary, addition of ENT to ICI significantly altered infiltration and function of innate immune cells, allowing for a more robust adaptive immune response. These findings provide a rationale for combination therapy in patients with immune-resistant tumors, including breast and pancreatic cancers.


Assuntos
Benzamidas/farmacologia , Carcinoma Ductal Pancreático/tratamento farmacológico , Neoplasias Mamárias Experimentais/tratamento farmacológico , Células Supressoras Mieloides/efeitos dos fármacos , Neoplasias Pancreáticas/tratamento farmacológico , Piridinas/farmacologia , Animais , Antineoplásicos/farmacologia , Antígeno CTLA-4/antagonistas & inibidores , Carcinoma Ductal Pancreático/mortalidade , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/imunologia , Masculino , Neoplasias Mamárias Experimentais/mortalidade , Neoplasias Mamárias Experimentais/patologia , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Células Supressoras Mieloides/imunologia , Neoplasias Pancreáticas/mortalidade , Neoplasias Pancreáticas/patologia , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Receptor de Morte Celular Programada 1/imunologia , Linfócitos T Reguladores/efeitos dos fármacos , Linfócitos T Reguladores/imunologia , Microambiente Tumoral/efeitos dos fármacos , Microambiente Tumoral/imunologia
8.
JCI Insight ; 3(13)2018 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-29997287

RESUMO

BACKGROUND: Immune checkpoint inhibitors provide significant clinical benefit to a subset of patients, but novel prognostic markers are needed to predict which patients will respond. This study was initiated to determine if features of patient T cell repertoires could provide insights into the mechanisms of immunotherapy, while also predicting outcomes. METHODS: We examined T cell receptor (TCR) repertoires in peripheral blood of 25 metastatic pancreatic cancer patients treated with ipilimumab with or without GVAX (a pancreatic cancer vaccine), as well as peripheral blood and tumor biopsies from 32 patients treated with GVAX and mesothelin-expressing Listeria monocytogenes with or without nivolumab. Statistics from these repertoires were then tested for their association with clinical response and treatment group. RESULTS: We demonstrate that, first, the majority of patients receiving these treatments experience a net diversification of their peripheral TCR repertoires. Second, patients receiving ipilimumab experienced larger changes in their repertoires, especially in combination with GVAX. Finally, both a low baseline clonality and a high number of expanded clones following treatment were associated with significantly longer survival in patients who received ipilimumab but not in patients receiving nivolumab. CONCLUSIONS: We show that these therapies have measurably different effects on the peripheral repertoire, consistent with their mechanisms of action, and demonstrate the potential for TCR repertoire profiling to serve as a biomarker of clinical response in pancreatic cancer patients receiving immunotherapy. In addition, our results suggest testing sequential administration of anti-CTLA-4 and anti-PD-1 antibodies to achieve optimal therapeutic benefit. TRIAL REGISTRATION: Samples used in this study were collected from the NCT00836407 and NCT02243371 clinical trials. FUNDING: Research supported by a Stand Up To Cancer Lustgarten Foundation Pancreatic Cancer Convergence Dream Team Translational Research grant (SU2C-AACR-DT14-14). Stand Up To Cancer is a program of the Entertainment Industry Foundation administered by the American Association for Cancer Research (AACR). Additional clinical trial funding was provided by AACR-Pancreatic Cancer Action Network Research Acceleration Network grant (14-90-25-LE), NCI SPORE in GI Cancer (CA062924), Quick-Trials for Novel Cancer Therapies: Exploratory Grants (R21CA126058-01A2), and the US Food and Drug Administration (R01FD004819). Research collaboration and financial support were provided by Adaptive Biotechnologies.


Assuntos
Anticorpos Monoclonais/uso terapêutico , Carcinoma Ductal Pancreático/imunologia , Imunoterapia/métodos , Neoplasias Pancreáticas/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Biomarcadores Tumorais/sangue , Antígeno CTLA-4/imunologia , Vacinas Anticâncer/uso terapêutico , Carcinoma Ductal Pancreático/terapia , Proteínas Ligadas por GPI/uso terapêutico , Humanos , Ipilimumab/uso terapêutico , Estimativa de Kaplan-Meier , Mesotelina , Nivolumabe/uso terapêutico , Neoplasias Pancreáticas/terapia , Receptor de Morte Celular Programada 1/imunologia , Estados Unidos , United States Food and Drug Administration , Neoplasias Pancreáticas
10.
J Otolaryngol Head Neck Surg ; 47(1): 3, 2018 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-29310703

RESUMO

BACKGROUND: Epistaxis is the most common emergent consultation to otolaryngology-head & neck surgery (OHNS) and with 60% of the population having experienced an episode and 1.6 in 10,000 requiring hospitalization in their lifetime. In preliminary studies Floseal® (Baxter, USA) Hemostatic Matrix has shown efficacy in up to 80% of persistent anterior epistaxis. We sought to evaluate the clinical efficacy and cost-effectiveness of Floseal® (Baxter, USA) compared to traditional nasal packing for persistent epistaxis. METHODS: A prospective, randomized controlled trial was conducted on all adult patients consulted to the OHNS service at the tertiary referral centers of the University of Alberta Hospital and Royal Alexandra Hospital for persistent epistaxis. Patients were randomized to the Floseal® (Baxter, USA) or traditional packing study arms. Our main clinical outcome measures were: 1) Hemostasis directly following treatment and at 48 h post-treatment, and 2) self-reported patient comfort at 48 h post-treatment. Further, trial data was used for a formal cost-effectiveness analysis to determine incremental cost-effectiveness ratio (ICER). Univariate sensitivity analysis and uncertainty analysis were performed. RESULTS: There were no significant differences between groups for initial hemostasis (76.9% vs. 84.6%, p = 1.000) or, hemostasis at 48 h (76.9% vs. 69.2%, p = 1.000), requirement for admission (15.4% vs. 46.1%, p = 0.2016) or 30-day re-presentation rates (15.4% vs. 46.1%, p = 0.2016). Floseal® (Baxter, USA) was superior for decreased pain during placement (2.42 vs. 7.77, p = 0.0022), treatment (0.50 vs. 4.46, p = 0.0007) and removal (0 vs. 3.85, p = 0.0021). Floseal® (Baxter, USA) provides an average $1567.61 per patient savings from the single-payer system point of view and has an ICER of - $11,891 per re-bleed prevented (95% CI: -$37,658 to +$473). Uncertainty analysis shows that Floseal® has >90% chance of not only being cost-effective, but the dominant (preferred) treatment. CONCLUSIONS: Floseal® (Baxter, USA) was demonstrated to be an effective, comfortable and cost-effective alternative treatment of persistent epistaxis when compared to traditional packing methods for patients referred to OHNS with a normal coagulation profile. TRIAL REGISTRATION: Trial registration number: NCT02488135 . Date registered: June 26, 2015.


Assuntos
Epistaxe/terapia , Esponja de Gelatina Absorvível/uso terapêutico , Técnicas Hemostáticas , Hemostáticos/uso terapêutico , Adulto , Idoso , Análise de Variância , Canadá , Intervalos de Confiança , Análise Custo-Benefício , Epistaxe/diagnóstico , Feminino , Esponja de Gelatina Absorvível/economia , Hemostáticos/economia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Recidiva , Índice de Gravidade de Doença , Tampões Cirúrgicos/estatística & dados numéricos , Resultado do Tratamento
12.
J Cell Biochem ; 117(7): 1707-17, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-26666591

RESUMO

FOXC1 is an important regulator of the initial steps in intramembranous and endochondral ossification processes. As BMP signalling is a key initiator of these processes, we sought to determine whether Foxc1 expression is regulated by such signalling factors. BMP4 treatment of C2C12 cells resulted in an induction in Foxc1 mRNA levels. Chromatin immunoprecipitation assays demonstrated that SMAD proteins interacted with the mouse Foxc1 promoter approximately 300 bp upstream of the transcription start site. This ChIP positive region was cloned into a luciferase reporter and demonstrated to be responsive to BMP4 stimulation. Reduction of Foxc1 levels in C2C12 cells though siRNA impaired BMP4 osteogenic differentiation. In contrast, BMP4 treatment repressed Foxc1 expression in 10T1/2 or D1-ORL mesenchymal cells and MC3T3 preosteoblasts. Finally, siRNA knock-down of Foxc1 in MC3T3 cells resulted in an induction of markers of osteoblast differentiation and an accelerated mineralization. These data indicate that Foxc1 expression is regulated by BMP4 and FOXC1 functions in the commitment of progenitor cells to the osteoblast fate and its expression is reduced when differentiation proceeds. J. Cell. Biochem. 117: 1707-1717, 2016. © 2015 Wiley Periodicals, Inc.


Assuntos
Proteína Morfogenética Óssea 4/metabolismo , Diferenciação Celular/fisiologia , Fatores de Transcrição Forkhead/biossíntese , Regulação da Expressão Gênica/fisiologia , Osteoblastos/metabolismo , Osteogênese/fisiologia , Proteínas Smad/metabolismo , Animais , Proteína Morfogenética Óssea 4/genética , Linhagem Celular , Fatores de Transcrição Forkhead/genética , Camundongos , Osteoblastos/citologia , Proteínas Smad/genética
13.
Genes Dev ; 25(12): 1328-43, 2011 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-21685367

RESUMO

Following DNA damage, cells typically delay cell cycle progression and inhibit cell division until their chromosomes have been repaired. The bacterial checkpoint systems responsible for these DNA damage responses are incompletely understood. Here, we show that Caulobacter crescentus responds to DNA damage by coordinately inducing an SOS regulon and inhibiting the master regulator CtrA. Included in the SOS regulon is sidA (SOS-induced inhibitor of cell division A), a membrane protein of only 29 amino acids that helps to delay cell division following DNA damage, but is dispensable in undamaged cells. SidA is sufficient, when overproduced, to block cell division. However, unlike many other regulators of bacterial cell division, SidA does not directly disrupt the assembly or stability of the cytokinetic ring protein FtsZ, nor does it affect the recruitment of other components of the cell division machinery. Instead, we provide evidence that SidA inhibits division by binding directly to FtsW to prevent the final constriction of the cytokinetic ring.


Assuntos
Proteínas de Bactérias/metabolismo , Caulobacter crescentus/genética , Caulobacter crescentus/metabolismo , Dano ao DNA/fisiologia , Proteínas de Membrana/metabolismo , Proteínas de Bactérias/genética , Caulobacter crescentus/citologia , Divisão Celular , Membrana Celular/metabolismo , Proteínas de Ligação a DNA , Regulação Bacteriana da Expressão Gênica , Proteínas de Membrana/genética , Mutação , Peptidoglicano/metabolismo , Fatores de Transcrição
15.
Chem Commun (Camb) ; (6): 586-8, 2007 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-17264899

RESUMO

The boron and aluminium dimers [Me2E(micro-py)]2 [E=B (1); Al (2)] are formed as mixtures of two isomers in which the group 13 centres are coordinated by the bridging 2-py ligands in a cis or trans manner, however, in contrast to previous studies, we find that simply heating the mixtures of these isomers of and gives the more thermodynamically stable (synthetically useful) trans isomers exclusively (the trans isomer being the only product in the case of the gallium analogue ).

16.
Chem Commun (Camb) ; (2): 198-200, 2005 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-15724184

RESUMO

The reactions of [MeAl(2-py)3Li.thf] (1) with FeCl2 or Cp2Mn in toluene-thf give simple access to the Group 13-transition metal heterometallic complexes [{MeAl(2-py)3}2M][M = Fe (2), Mn (3)]; complex has been shown to be a highly selective styrene epoxidation catalyst in air.

18.
Dalton Trans ; (14): 2051-2, 2004 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-15249934

RESUMO

The reaction of (Me(3)Si)(3)SiK[middle dot]18-crown-6 with SbCl(3)(3 : 1 equiv.) provides a simple route to the title complex [(Me(3)Si)(3)SiSb](4). The potassium base initially acts as a nucleophile and then as a coupling agent, forming Sb-Sb bonds.

19.
Chem Commun (Camb) ; (11): 1288-9, 2003 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-12809234

RESUMO

The reaction of CyPHNa with Sn(NMe2)2 in the presence of PMDETA (= (Me2NCH2CH2)2NMe) gives the title compound [(Sn(mu-PCy))3(Na x PMDETA)2] (1), containing an electron-deficient [(Sn(mu-PCy))]3(2-) dianion with a novel two-electron, three centre (2e-3c) bonding arrangement.

20.
Inorg Chem ; 41(6): 1492-501, 2002 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-11896718

RESUMO

In contrast to the reactions of Sn(NMe(2))(2) with unfunctionalized primary amines (RNH(2)), which yield the simple imido Sn(II) cubanes [SnNR](4), the reactions of 2-pyridyl or 2-pyrimidinyl amines give the mixed-oxidation-state Sn(II)/Sn(IV) double cubanes [Sn(7)(NR)(8)]. In addition to [Sn(7)[2-N(5-Mepy)](8)] x 2thf (1 x 2thf) (py = pyridine) and [Sn(7)[2-N(pm)](8)] x 0.33thf (2 x 0.33thf) (pm = pyrimidine), which were communicated previously, the syntheses and structures of the new complexes [Sn(7)[2-N(4-Mepm)](8)] x 2thf (3 x 2thf), [Sn(7)[2-N(4,6-Me(2)pm)](8)] x 4thf (4 x 4thf), [Sn(7)[2-N(4-Me-6-MeO-pm)](8)] (5), and [Sn(7)[2-N(4-MeO-6-MeO-pm)](8)] (6) are reported. Model DFT calculations on the reactions of Sn(NMe(2))(2) with 2-pmNH(2) or PhNH(2), producing the cubanes [Sn[2-N(pm)]](4) and [SnNPh](4) (respectively), and the corresponding double cubanes [Sn(7)[2-N(pm)](8)] and [Sn(7)(NPh)(8)], show that the presence of intramolecular Sn...N bonding which spans the cubane halves of the complexes is crucial to the formation of the double-cubane structure.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...