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1.
Eur J Vasc Endovasc Surg ; 67(4): 540-553, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38428672

RESUMO

OBJECTIVE: Treatment of juxtarenal and complex neck abdominal aortic aneurysms (AAAs) is now commonly by endovascular rather than open surgical repair (OSR). Published comparisons show poor validity and scientific precision. UK-COMPASS is a comparative cohort study of endovascular treatments vs. OSR for patients with an AAA unsuitable for standard on label endovascular aneurysm repair (EVAR). METHODS: All procedures for AAA in England (November 2017 to October 2019) were identified, AAA anatomy assessed in a Corelab, peri-operative risk scores determined, and propensity scoring used to identify patients suitable for either endovascular treatment or OSR. Patients were stratified by aneurysm neck length (0 - 4 mm, 5 - 9 mm, or ≥ 10 mm) and operative risk; the highest quartile was considered high risk and the remainder standard risk. Death was the primary outcome measure. Endovascular treatments included fenestrated EVAR (FEVAR) and off label standard EVAR (± adjuncts). RESULTS: Among 8 994 patients, 2 757 had AAAs that were juxtarenal, short neck, or complex neck in morphology. Propensity score stratification and adjustment method comparisons included 1 916 patients. Widespread off label use of standard EVAR devices was noted (35.6% of patients). The adjusted peri-operative mortality rate was 2.9%, lower for EVAR (1.2%; p = .001) and FEVAR (2.2%; p = .001) than OSR (4.5%). In standard risk patients with a 0 - 4 mm neck, the mortality rate was 7.4% following OSR and 2.3% following FEVAR. Differences were smaller for patients with a neck length ≥ 5 mm: 2.1% OSR vs. 1.0% FEVAR. At 3.5 years of follow up, the overall mortality rate was 20.7% in the whole study population, higher following FEVAR (27.6%) and EVAR (25.2%) than after OSR (14.2%). However, in the 0 - 4 mm neck subgroup, overall survival remained equivalent. The aneurysm related mortality rate was equivalent between treatments, but re-intervention was more common after EVAR and FEVAR than OSR. CONCLUSION: FEVAR proves notably safer than OSR in the peri-operative period for juxtarenal aneurysms (0 - 4 mm neck length), with comparable midterm survival. For patients with short neck (5 - 9 mm) and complex neck (≥ 10 mm) AAAs, overall survival was worse in endovascularly treated patients compared with OSR despite relative peri-operative safety. This warrants further research and a re-appraisal of the current clinical application of endovascular strategies, particularly in patients with poor general survival outlook owing to comorbidity and age.

4.
Gut ; 72(3): 535-548, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36109153

RESUMO

OBJECTIVE: GATA6 is a key regulator of the classical phenotype in pancreatic ductal adenocarcinoma (PDAC). Low GATA6 expression associates with poor patient outcome. GATA4 is the second most expressed GATA factor in the pancreas. We assessed whether, and how, GATA4 contributes to PDAC phenotype and analysed the association of expression with outcome and response to chemotherapy. DESIGN: We analysed PDAC transcriptomic data, stratifying cases according to GATA4 and GATA6 expression and identified differentially expressed genes and pathways. The genome-wide distribution of GATA4 was assessed, as well as the effects of GATA4 knockdown. A multicentre tissue microarray study to assess GATA4 and GATA6 expression in samples (n=745) from patients with resectable was performed. GATA4 and GATA6 levels were dichotomised into high/low categorical variables; association with outcome was assessed using univariable and multivariable Cox regression models. RESULTS: GATA4 messenger RNA is enriched in classical, compared with basal-like tumours. We classified samples in 4 groups as high/low for GATA4 and GATA6. Reduced expression of GATA4 had a minor transcriptional impact but low expression of GATA4 enhanced the effects of GATA6 low expression. GATA4 and GATA6 display a partially overlapping genome-wide distribution, mainly at promoters. Reduced expression of both proteins in tumours was associated with the worst patient survival. GATA4 and GATA6 expression significantly decreased in metastases and negatively correlated with basal markers. CONCLUSIONS: GATA4 and GATA6 cooperate to maintain the classical phenotype. Our findings provide compelling rationale to assess their expression as biomarkers of poor prognosis and therapeutic response.


Assuntos
Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Humanos , Neoplasias Pancreáticas/patologia , Pâncreas/patologia , Carcinoma Ductal Pancreático/patologia , Perfilação da Expressão Gênica , Fator de Transcrição GATA6/genética , Fator de Transcrição GATA4/genética , Fator de Transcrição GATA4/metabolismo
5.
BMJ Open ; 12(10): e068010, 2022 10 10.
Artigo em Inglês | MEDLINE | ID: mdl-36216424

RESUMO

INTRODUCTION: Pancreatic cancer is a leading cause of cancer deaths worldwide. Screening for this disease has potential to improve survival. It is not feasible, with current screening modalities, to screen the asymptomatic adult population. However, screening of individuals in high-risk groups is recommended. Our study aims to provide resources and data that will inform strategies to screen individuals with new-onset diabetes (NOD) for pancreatic cancer. METHODS AND ANALYSIS: The United Kingdom Early Detection Initiative (UK-EDI) for pancreatic cancer is a national, prospective, observational cohort study that aims to recruit 2500 individuals with NOD (<6 months postdiagnosis) aged 50 years and over, with follow-up every 6 months, over a 3-year period. For study eligibility, diagnosis of diabetes is considered to be clinical measurement of haemoglobin A1c ≥48 mmol/mol. Detailed clinical information and biospecimens will be collected at baseline and follow-up to support the development of molecular, epidemiological and demographic biomarkers for earlier detection of pancreatic cancer in the high-risk NOD group. Socioeconomic impacts and cost-effectiveness of earlier detection of pancreatic cancer in individuals with NOD will be evaluated. The UK-EDI NOD cohort will provide a bioresource for future early detection research to be conducted. ETHICS AND DISSEMINATION: The UK-EDI study has been reviewed and approved by the London-West London and GTAC Research Ethics Committee (Ref 20/LO/0058). Study results will be disseminated through presentations at national and international symposia and publication in peer-reviewed, Open Access journals.


Assuntos
Diabetes Mellitus , Neoplasias Pancreáticas , Idoso , Estudos de Coortes , Diabetes Mellitus/diagnóstico , Diabetes Mellitus/epidemiologia , Detecção Precoce de Câncer/métodos , Hemoglobinas Glicadas , Humanos , Pessoa de Meia-Idade , Estudos Multicêntricos como Assunto , Estudos Observacionais como Assunto , Neoplasias Pancreáticas/diagnóstico , Neoplasias Pancreáticas/epidemiologia , Estudos Prospectivos , Reino Unido/epidemiologia , Neoplasias Pancreáticas
6.
Sci Rep ; 12(1): 9654, 2022 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-35688935

RESUMO

Cryogels consisting of polyvinyl alcohol and iron (II, III) oxide magnetic nanoparticles coated with a model drug-acetaminophen, were developed as a tunable platform for thermally triggered drug release, based on shape-selective heat transfer. Two different shapes of cryogels; discs and spherical caps, were formed via adding polymer-nanoparticle-drug mixtures into 3D printed molds, followed by freeze-thawing five times. No additional chemical crosslinking agents were used for gel formation and the iron oxide nanoparticles were coated with acetaminophen using only citric acid as a hydrogen-bonding linker. The two gel shapes displayed varying levels of acetaminophen release within 42-50 °C, which are ideal temperatures for hyperthermia induced drug delivery. The amount and time of drug-release were shown to be tunable by changing the temperature of the medium and the shape of the gels, while keeping all other factors (ex. gel volume, surface area, polymer/nanoparticle concentrations and drug-loading) constant. The discs displayed higher drug release at all temperatures while being particularly effective at lower temperatures (42-46 °C), in contrast to the spherical caps, which were more effective at higher temperatures (48-50 °C). Magnetic hyperthermia-mediated thermal imaging and temperature profiling studies revealed starkly different heat transfer behavior from the two shapes of gels. The disc gels retained their structural integrity up to 51 °C, while the spherical caps were stable up to 59 °C, demonstrating shape-dependent robustness. The highly customizable physicochemical features, facile synthesis, biocompatibility and tunable drug release ability of these cryogels offer potential for their application as a low cost, safe and effective platform for hyperthermia-mediated drug delivery, for external applications such as wound care/muscle repair or internal applications such as melanoma treatment.


Assuntos
Criogéis , Hipertermia Induzida , Acetaminofen , Géis/química , Humanos , Hipertermia , Hipertermia Induzida/métodos , Fenômenos Magnéticos , Polímeros/química
7.
Eur J Vasc Endovasc Surg ; 63(5): 696-706, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35221243

RESUMO

OBJECTIVE: Abdominal aortic aneurysms (AAAs) with adverse morphology of the aneurysm neck are "complex". Techniques employed to repair complex aneurysms include open surgical repair (OSR) and a number of on label endovascular techniques such as fenestrated endovascular aneurysm repair (FEVAR) and endovascular aneurysm repair (EVAR) with adjuncts (including chimneys and endo-anchors), as well as off label use of standard EVAR. The aim was to conduct a network meta-analysis (NMA) of published comparative outcomes. DATA SOURCES: An electronic search was performed in Embase, MEDLINE, and the Cochrane Central Register of Controlled Trials (CENTRAL). These databases were interrogated using the PubMed interface and the Healthcare Databases Advanced Search (HDAS) interface developed by the National Institute of Health and Care Excellence. REVIEW METHODS: Online databases were interrogated up to April 2020. Studies were included if they compared outcomes between at least two methods of repair for complex aneurysms (those with at least one adverse neck feature: absent/short neck, conicality, angulation, calcification, large diameter, and thrombus). The primary outcome measure was peri-operative death. Pre-registration was done in PROSPERO (CRD42020177482). RESULTS: The search identified 24 observational studies and 7854 patients who underwent OSR, FEVAR, off label EVAR, or chimney EVAR. No comparative studies included EVAR with endo-anchors. NMA was performed on 23 studies that reported outcomes of aneurysms with short/absent infrarenal neck. Compared with OSR, off label EVAR (relative risk [RR] 0.10, 95% confidence interval [CI] 0.01 - 0.41) and FEVAR (RR 0.62, 95% CI 0.32-0.94) were associated with lower peri-operative mortality. This difference was not seen at the midterm follow up (30 months). Compared with OSR, FEVAR was associated with a lower peri-operative myocardial infarction (MI) rate (RR 0.37, 95% CI 0.16 - 0.62) but a higher midterm re-intervention rate (hazard ratio 1.65, 95% CI 1.04 - 2.66). All studies had a "moderate" or "high" risk of bias. Confidence in the network findings (GRADE) was generally "low". CONCLUSION: This NMA demonstrated a peri-operative survival benefit for off label EVAR and FEVAR compared with OSR, potentially due to reduced risk of MI. FEVAR carries a greater midterm re-intervention risk than OSR, with potential implications for cost effectiveness. There is paucity of comparative data for cases with adverse neck features other than short length.

8.
Pharm Stat ; 21(3): 514-524, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-34859565

RESUMO

The problem of associating a continuous covariate, or biomarker, against a time-to-event outcome, is that it often requires categorisation of the covariate. This can lead to bias, loss of information and a poor representation of any underlying relationship. Here, two methods are proposed for estimating the effects of a continuous covariate on a time-to-event endpoint using weighted kernel estimators. The first method aims to estimate a density function for a time-to-event endpoint conditional on some covariate value whilst the second uses a joint density estimator. The results are visualisations in the form of surface plots that show the effects of a covariate without any need for categorisation. Both methods can aid interpretation and analysis of covariates against a time-to-event endpoint.


Assuntos
Viés , Simulação por Computador , Humanos
9.
BMJ Open ; 11(11): e054493, 2021 11 30.
Artigo em Inglês | MEDLINE | ID: mdl-34848524

RESUMO

INTRODUCTION: In one-third of all abdominal aortic aneurysms (AAAs), the aneurysm neck is short (juxtarenal) or shows other adverse anatomical features rendering operations more complex, hazardous and expensive. Surgical options include open surgical repair and endovascular aneurysm repair (EVAR) techniques including fenestrated EVAR, EVAR with adjuncts (chimneys/endoanchors) and off-label standard EVAR. The aim of the UK COMPlex AneurySm Study (UK-COMPASS) is to answer the research question identified by the National Institute for Health Research Health Technology Assessment (NIHR HTA) Programme: 'What is the clinical and cost-effectiveness of strategies for the management of juxtarenal AAA, including fenestrated endovascular repair?' METHODS AND ANALYSIS: UK-COMPASS is a cohort study comparing clinical and cost-effectiveness of different strategies used to manage complex AAAs with stratification of physiological fitness and anatomical complexity, with statistical correction for baseline risk and indication biases. There are two data streams. First, a stream of routinely collected data from Hospital Episode Statistics and National Vascular Registry (NVR). Preoperative CT scans of all patients who underwent elective AAA repair in England between 1 November 2017 and 31 October 2019 are subjected to Corelab analysis to accurately identify and include every complex aneurysm treated. Second, a site-reported data stream regarding quality of life and treatment costs from prospectively recruited patients across England. Site recruitment also includes patients with complex aneurysms larger than 55 mm diameter in whom an operation is deferred (medical management). The primary outcome measure is perioperative all-cause mortality. Follow-up will be to a median of 5 years. ETHICS AND DISSEMINATION: The study has received full regulatory approvals from a Research Ethics Committee, the Confidentiality Advisory Group and the Health Research Authority. Data sharing agreements are in place with National Health Service Digital and the NVR. Dissemination will be via NIHR HTA reporting, peer-reviewed journals and conferences. TRIAL REGISTRATION NUMBER: ISRCTN85731188.


Assuntos
Aneurisma da Aorta Abdominal , Implante de Prótese Vascular , Procedimentos Endovasculares , Aneurisma da Aorta Abdominal/diagnóstico por imagem , Aneurisma da Aorta Abdominal/cirurgia , Estudos de Coortes , Humanos , Complicações Pós-Operatórias , Qualidade de Vida , Fatores de Risco , Medicina Estatal , Resultado do Tratamento , Reino Unido
10.
Front Med (Lausanne) ; 7: 585744, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33415115

RESUMO

Declining life expectancy and increasing all-cause mortality in the United States have been associated with unhealthy behaviors, socioecological factors, and preventable disease. A growing body of basic science, clinical research, and population health evidence points to the benefits of healthy behaviors, environments and policies to maintain health and prevent, treat, and reverse the root causes of common chronic diseases. Similarly, innovations in research methodologies, standards of evidence, emergence of unique study cohorts, and breakthroughs in data analytics and modeling create new possibilities for producing biomedical knowledge and clinical translation. To understand these advances and inform future directions research, The Lifestyle Medicine Research Summit was convened at the University of Pittsburgh on December 4-5, 2019. The Summit's goal was to review current status and define research priorities in the six core areas of lifestyle medicine: plant-predominant nutrition, physical activity, sleep, stress, addictive behaviors, and positive psychology/social connection. Forty invited subject matter experts (1) reviewed existing knowledge and gaps relating lifestyle behaviors to common chronic diseases, such as cardiovascular disease, diabetes, many cancers, inflammatory- and immune-related disorders and other conditions; and (2) discussed the potential for applying cutting-edge molecular, cellular, epigenetic and emerging science knowledge and computational methodologies, research designs, and study cohorts to accelerate clinical applications across all six domains of lifestyle medicine. Notably, federal health agencies, such as the Department of Defense and Veterans Administration have begun to adopt "whole-person health and performance" models that address these lifestyle and environmental root causes of chronic disease and associated morbidity, mortality, and cost. Recommendations strongly support leveraging emerging research methodologies, systems biology, and computational modeling in order to accelerate effective clinical and population solutions to improve health and reduce societal costs. New and alternative hierarchies of evidence are also be needed in order to assess the quality of evidence and develop evidence-based guidelines on lifestyle medicine. Children and underserved populations were identified as prioritized groups to study. The COVID-19 pandemic, which disproportionately impacts people with chronic diseases that are amenable to effective lifestyle medicine interventions, makes the Summit's findings and recommendations for future research particularly timely and relevant.

11.
ACS Omega ; 3(4): 4342-4351, 2018 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-29732454

RESUMO

We present the synthesis of nylon-12 scaffolds by 3D printing and demonstrate their versatility as matrices for cell growth, differentiation, and biomineral formation. We demonstrate that the porous nature of the printed parts makes them ideal for the direct incorporation of preformed nanomaterials or material precursors, leading to nanocomposites with very different properties and environments for cell growth. Additives such as those derived from sources such as tetraethyl orthosilicate applied at a low temperature promote successful cell growth, due partly to the high surface area of the porous matrix. The incorporation of presynthesized iron oxide nanoparticles led to a material that showed rapid heating in response to an applied ac magnetic field, an excellent property for use in gene expression and, with further improvement, chemical-free sterilization. These methods also avoid changing polymer feedstocks and contaminating or even damaging commonly used selective laser sintering printers. The chemically treated 3D printed matrices presented herein have great potential for use in addressing current issues surrounding bone grafting, implants, and skeletal repair, and a wide variety of possible incorporated material combinations could impact many other areas.

12.
Pediatr Surg Int ; 34(3): 331-333, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29214341

RESUMO

PURPOSE: Classical slipping rib syndrome (SRS) can be subclassified based on anatomical location. We describe our experience with three patients suffering from symptomatic sternocostal slipping rib syndrome (SCSRS), a much less common variant of SRS. METHODS: This was a retrospective review of patients with SRS from 1988 to 2016. Described is our experience. RESULTS: Of 44 patients identified with SRS, three patients underwent operations for SCSRS variant. All three had significant pain and point tenderness at the sternocostal junction, and all experienced a popping sensation localized to this area. The mean age at onset was 14.3 years and mean time to diagnosis was 1.3 years. All patients experienced total resolution of symptoms following localized excision of the offending cartilage. CONCLUSIONS: A high index of suspicion based on history and physical examination are key to the early diagnosis of SCSRS. Excision of the symptomatic cartilage is effective for treatment.


Assuntos
Dor no Peito/etiologia , Cartilagem Costal/fisiopatologia , Ligamentos/fisiopatologia , Costelas/fisiopatologia , Adolescente , Cartilagem Costal/cirurgia , Feminino , Humanos , Ligamentos/cirurgia , Masculino , Estudos Retrospectivos , Costelas/cirurgia , Síndrome
13.
Pediatr Surg Int ; 33(8): 887-891, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28616724

RESUMO

BACKGROUND: Limited therapeutic options exist for rectal and vaginal venous malformations (VM). We describe our center's experience using Nd:YAG laser for targeted ablation of abnormal veins to treat mucosally involved pelvic VM. METHODS: Records of patients undergoing non-contact Nd:YAG laser therapy of pelvic VM at a tertiary children's hospital were reviewed. Symptoms, operative findings and details, complications, and outcomes were evaluated. RESULTS: Nine patients (age 0-24) underwent Nd:YAG laser therapy of rectal and/or vaginal VM. Rectal bleeding was present in all patients and vaginal bleeding in all females (n = 5). 5/7 patients had extensive pelvic involvement on MRI. Typical settings were 30 (rectum) and 20-25 W (vagina), with 0.5-1.0 s pulse duration. Patients underwent the same-day discharge. Treatment intervals ranged from 14 to 180 (average = 56) weeks, with 6.1-year mean follow-up. Five patients experienced symptom relief with a single treatment. Serial treatments managed recurrent bleeding successfully in all patients, with complete resolution of vaginal lesions in 40% of cases. No complications occurred. CONCLUSIONS: Nd:YAG laser treatment of rectal and vaginal VM results in substantial improvement and symptom control, with low complication risk. Given the high morbidity of surgical resection, Nd:YAG laser treatment of pelvic VM should be considered as first line therapy.


Assuntos
Lasers de Estado Sólido/uso terapêutico , Reto/irrigação sanguínea , Reto/cirurgia , Vagina/irrigação sanguínea , Vagina/cirurgia , Malformações Vasculares/cirurgia , Adolescente , Criança , Pré-Escolar , Feminino , Seguimentos , Humanos , Lactente , Masculino , Resultado do Tratamento , Adulto Jovem
14.
Int J Oncol ; 50(3): 768-772, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28098864

RESUMO

There is no standard of care in the UK or Ireland for second-line chemotherapy for patients with advanced transitional cell carcinoma (TCCU). Vinflunine is approved for TCCU patients who have failed a platinum-based regimen, and is standard of care in Europe but is not routinely available in the UK. Data were collected retrospectively on patients who received vinfluine as a second-line treatment. The aims were to document the toxicity and efficacy in a real life setting. Data were collected on 49 patients from 9 sites across the UK and Ireland [median age, 64 (IQR, 57-70) years, 33 males]. All patients had advanced metastatic TCCU. Thirteen patients had bone or liver metastases, 4 patients had PS 2 and 11 patients had HB <10. Median vinflunine administration was 3.5 cycles (range 1-18). Most common grade 3-4 toxicities were constipation (4 patients) and fatigue (3 patients). Partial response rate was 29% (14 PR, 11 SD, 19 PD, 4 NE, 1 not available). Median OS was 9.1 (6.0, 12.7) months. Results are consistent with real life data from Europe. Toxicity is further reduced with prophylactic laxative and oral antibiotics. Vinflunine is an efficient and tolerable second line treatment in advanced TCCU.


Assuntos
Antineoplásicos Fitogênicos/uso terapêutico , Carcinoma de Células de Transição/tratamento farmacológico , Neoplasias da Bexiga Urinária/tratamento farmacológico , Vimblastina/análogos & derivados , Idoso , Neoplasias Ósseas/secundário , Carcinoma de Células de Transição/patologia , Intervalo Livre de Doença , Feminino , Humanos , Irlanda , Neoplasias Hepáticas/secundário , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do Tratamento , Reino Unido , Neoplasias da Bexiga Urinária/patologia , Urotélio/patologia , Vimblastina/uso terapêutico
16.
Prev Med ; 72: 70-5, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25572622

RESUMO

OBJECTIVE: Policies to promote active transportation are emerging as a best practice to increase physical activity, yet relatively little is known about public opinion on utilizing transportation funds for such investments. This study sought to assess public awareness of and support for investments in walking and biking infrastructure in Los Angeles County. METHOD: In the fall of 2013, the Los Angeles County Department of Public Health conducted a telephone survey with a random sample of registered voters in the region. The survey asked respondents to report on the presence and importance of walking and biking infrastructure in their community, travel behaviors and preferences, and demographics. RESULTS: One thousand and five interviews were completed (response rate 20%, cooperation rate 54%). The majority of participants reported walking, biking, and bus/rail transportation investments as being important. In addition, participants reported a high level of support for redirecting transportation funds to active transportation investment - the population average was 3.28 (between 'strongly' and 'somewhat' support) on a 4 point Likert scale. CONCLUSION: Voters see active transportation infrastructure as being very important and support redirecting funding to improve the infrastructure. These findings can inform policy-decisions and planning efforts in the jurisdiction.


Assuntos
Ciclismo/estatística & dados numéricos , Planejamento Ambiental , Opinião Pública , Política Pública , Caminhada/estatística & dados numéricos , Adolescente , Adulto , Idoso , Estudos Transversais , Coleta de Dados , Exercício Físico , Feminino , Comportamentos Relacionados com a Saúde , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Los Angeles , Masculino , Pessoa de Meia-Idade , Inquéritos e Questionários , Meios de Transporte/estatística & dados numéricos , Adulto Jovem
17.
Nucleic Acids Res ; 42(13): 8605-20, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24957602

RESUMO

Post-transcriptional steps of gene expression are regulated by RNA binding proteins. Major progress has been made in characterizing RNA-protein interactions, from high resolution structures to transcriptome-wide profiling. Due to the inherent technical challenges, less attention has been paid to the way in which proteins with multiple RNA binding domains engage with target RNAs. We have investigated how the four RNA recognition motif (RRM) domains of Polypyrimidine tract binding (PTB) protein, a major splicing regulator, interact with FAS pre-mRNA under conditions in which PTB represses FAS exon 6 splicing. A combination of tethered hydroxyl radical probing, targeted inactivation of individual RRMs and single molecule analyses revealed an unequal division of labour between the four RRMs of PTB. RNA binding by RRM4 is the most important for function despite the low intrinsic binding specificity and the complete lack of effect of disrupting individual RRM4 contact points on the RNA. The ordered RRM3-4 di-domain packing provides an extended binding surface for RNA interacting at RRM4, via basic residues in the preceding linker. Our results illustrate how multiple alternative low-specificity binding configurations of RRM4 are consistent with repressor function as long as the overall ribonucleoprotein architecture provided by appropriate di-domain packing is maintained.


Assuntos
Processamento Alternativo , Proteína de Ligação a Regiões Ricas em Polipirimidinas/química , Proteína de Ligação a Regiões Ricas em Polipirimidinas/metabolismo , Precursores de RNA/metabolismo , RNA Mensageiro/metabolismo , Receptor fas/genética , Sítios de Ligação , Mutação , Proteína de Ligação a Regiões Ricas em Polipirimidinas/genética , Ligação Proteica , Estrutura Terciária de Proteína , Precursores de RNA/química , RNA Mensageiro/química , Receptor fas/metabolismo
18.
J Pediatr Surg ; 48(12): 2506-10, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24314194

RESUMO

PURPOSE: The occurrence of gastrocutaneous fistula (GCF) is a well-known complication after gastrostomy tube placement. We explore multiple factors to ascertain their impact on the rate of persistent GCF formation. METHODS: We retrospectively reviewed patient records for all gastrostomies (GT) constructed at our institution from 2007 to 2011. Association of GCF with method of placement, concomitant fundoplication, neurologic findings, duration of therapy, and demographics was evaluated using logistic regression. RESULTS: Nine hundred fifty patients had GTs placed, of which 148 patients had GTs removed and 47 (32%) of 148 required surgical closure secondary to persistent GCF. Laparoscopic and open procedures comprised 79 (53%) of 148 and 69 (47%) of 148, respectively. Seventeen (22%) patients in the laparoscopic group developed persistent GCF, compared to 30 (43%) in the open group (P=0.035, OR=2.52). Seventy-one patients had concomitant Nissen fundoplication. Thirty-one (44%) developed GCF, compared to 16 (21%) without a Nissen (P=0.002, OR=4.94). Patients with button in place for 303 days had persistent GCF incidence of 23%, compared to 45% at 540 days (P<0.001, OR=3.51) and 50% at 850 days (P=0.011, OR=4.51). Patients with device placed at 1.8 months of age were more likely to develop GCF compared to those with device placed at 8.9 months of age (P=0.017, OR=2.35). CONCLUSION: Open operations, concurrent Nissen and younger age at placement were all statistically significant factors causing persistent GCF.


Assuntos
Fístula Cutânea/etiologia , Fundoplicatura , Fístula Gástrica/etiologia , Gastrostomia/métodos , Laparoscopia , Complicações Pós-Operatórias/etiologia , Criança , Pré-Escolar , Fístula Cutânea/epidemiologia , Fístula Cutânea/cirurgia , Feminino , Seguimentos , Fístula Gástrica/epidemiologia , Fístula Gástrica/cirurgia , Humanos , Incidência , Modelos Logísticos , Masculino , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/cirurgia , Curva ROC , Estudos Retrospectivos , Fatores de Risco
20.
Artigo em Inglês | MEDLINE | ID: mdl-23378589

RESUMO

Internal ribosome entry sites/segments (IRESs) were first discovered over 20 years ago in picornaviruses, followed by the discovery of two other types of IRES in hepatitis C virus (HCV), and the dicistroviruses, which infect invertebrates. In the meantime, reports of IRESs in eukaryotic cellular mRNAs started to appear, and the list of such putative IRESs continues to grow to the point in which it now stands at ~100, 80% of them in vertebrate mRNAs. Despite initial skepticism from some quarters, there now seems universal agreement that there is genuine internal ribosome entry on the viral IRESs. However, the same cannot be said for cellular mRNA IRESs, which continue to be shrouded in controversy. The aim of this article is to explain why vertebrate mRNA IRESs remain controversial, and to discuss ways in which these controversies might be resolved.


Assuntos
RNA Mensageiro/química , Vertebrados/genética , Animais , Sítios de Ligação , Conformação de Ácido Nucleico , Iniciação Traducional da Cadeia Peptídica , Fatores de Iniciação de Peptídeos/química , Fatores de Iniciação de Peptídeos/fisiologia , RNA Mensageiro/classificação , RNA Viral/química , RNA Viral/classificação , Ribossomos/química , Ribossomos/metabolismo
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