RESUMEN
During activation the platelet cytoskeleton is reorganized, inducing adhesion to the extracellular matrix and cell spreading. These processes are critical for wound healing and clot formation. Initially, this task relies on the formation of strong cellular-extracellular matrix interactions, exposed in subendothelial lesions. Despite the medical relevance of these processes, there is a lack of high-resolution structural information on the platelet cytoskeleton controlling cell spreading and adhesion. Here, we present in situ structural analysis of membrane receptors and the underlying cytoskeleton in platelet protrusions by applying cryoelectron tomography to intact platelets. We utilized three-dimensional averaging procedures to study receptors at the plasma membrane. Analysis of substrate interaction-free receptors yielded one main structural class resolved to 26 Å, resembling the αIIbß3 integrin folded conformation. Furthermore, structural analysis of the actin network in pseudopodia indicates a nonuniform polarity of filaments. This organization would allow generation of the contractile forces required for integrin-mediated cell adhesion.
Asunto(s)
Citoesqueleto de Actina , Actinas/química , Plaquetas/fisiología , Membrana Celular/metabolismo , Extensiones de la Superficie Celular/fisiología , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/química , Actinas/metabolismo , Adhesión Celular , Humanos , Activación Plaquetaria , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/metabolismoRESUMEN
BACKGROUND AND AIMS: Conventional endoscopic mucosal resection (CEMR) is the standard modality for removing nonpedunculated colorectal lesions. Underwater endoscopic mucosal resection (UEMR) has emerged as an alternative method. There are few comparative studies between these techniques, especially evaluating recurrence. Therefore, the purpose of this trial was to compare CEMR and UEMR for the resection of colorectal lesions with respect to efficacy, safety, and recurrence rate. METHODS: This was a randomized controlled trial of UEMR versus CEMR for naïve and nonpedunculated lesions measuring between 10 and 40 mm. The primary outcome was adenoma recurrence at 6 months after the resection. Secondary outcomes were rates of technical success, en bloc resection, and adverse events. Block randomization was used to assign patients. Tattooing was performed to facilitate localization of the scars and eventual recurrences. Endoscopic follow-up was scheduled at 6 months after the procedure. The sites of resections were examined with white-light imaging, narrow-band imaging (NBI), and conventional chromoscopy with indigo carmine followed by biopsies. RESULTS: One hundred five patients with 120 lesions were included, with a mean size of 17.5 ± 7.1 (SD) mm. Sixty-one lesions were resected by UEMR and 59 by CEMR. The groups were similar at baseline regarding age, sex, average size, and histologic type. Lesions in the proximal colon in the CEMR group corresponded to 83% and in the UEMR group to 67.8% (P = .073). There was no difference between groups regarding success rate (1 failure in each group) and en bloc resection rate (60.6% UEMR vs 54.2% CEMR, P = .48). Intraprocedural bleeding was observed in 5 CEMRs (8.5%) and 2 UEMRs (3.3%) (P = .27). There was no perforation or delayed hemorrhage in either groups. Recurrence rate was higher in the CEMR arm (15%) than in the UEMR arm (2%) (P = .031). Therefore, the relative risk of 6-month recurrence rate in the CEMR group was 7.5-fold higher (95% CI, 0.98-58.20), with a number needed to treat of 7.7 (95% CI, 40.33-4.22). The higher recurrence rate in the CEMR group persisted only for lesions measuring 21 to 40 mm (35.7% vs 0%; P = .04). CONCLUSION: This study demonstrated that UEMR was associated with a lower adenoma recurrence rate than was CEMR. Both endoscopic techniques were effective and had similar rates of adverse events for the treatment of nonpedunculated colorectal lesions.
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Adenoma , Neoplasias Colorrectales , Resección Endoscópica de la Mucosa , Humanos , Colonoscopía/métodos , Neoplasias Colorrectales/cirugía , Neoplasias Colorrectales/patología , Adenoma/cirugía , Adenoma/patología , Resección Endoscópica de la Mucosa/métodos , Mucosa Intestinal/cirugía , Mucosa Intestinal/patologíaRESUMEN
Self-expanding metallic stents (SEMS) are considered the treatment of choice for the palliation of dysphagia and fistulas in inoperable esophageal neoplasms. However, the safety of SEMSs in patients who received or who will be submitted to radiotherapy (RT) is uncertain. The study aimed to evaluate the impact of RT on adverse events (AEs) in patients with esophageal cancer with SEMSs. This is a retrospective study conducted at a tertiary cancer hospital from 2009 to 2018. We collected information regarding RT, the histological type of the tumor, the model of SEMSs and AEs after stent placement. Three hundred twenty-three patients with malignant stenosis or fistula were treated with SEMSs. The predominant histological type was squamous cell carcinoma (79.6%). A total of 282 partially covered and 41 fully covered SEMSs were inserted. Of the 323 patients, 182 did not received RT, 118 received RT before SEMS placement and 23 after. Comparing the group that received RT before stent insertion with the group that did not, the first one presented a higher frequency of severe pain (9/118 7.6% vs. 3/182 1.6%; P = 0.02). The group treated with RT after stent placement had a higher risk of global AEs (13/23 56.5% vs. 63/182 34.6%; P = 0.019), ingrowth/overgrowth (6/23 26.1% vs. 21/182 11.5%; P = 0.045) and gastroesophageal reflux (2/23 8.7% vs. 2/182 1.1%; P = 0.034). Treatment with RT before stent placement in patients with inoperable esophageal neoplasm prolongs survival and is associated with an increased risk of severe chest pain. Treatment with RT of patients with an esophageal stent increases the frequency of minor, not life-threatening AEs.
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Trastornos de Deglución , Neoplasias Esofágicas , Estenosis Esofágica , Stents Metálicos Autoexpandibles , Humanos , Estudios Retrospectivos , Resultado del Tratamiento , Stents/efectos adversos , Neoplasias Esofágicas/terapia , Neoplasias Esofágicas/complicaciones , Trastornos de Deglución/etiología , Trastornos de Deglución/terapia , Cuidados Paliativos , Stents Metálicos Autoexpandibles/efectos adversos , Estenosis Esofágica/terapiaRESUMEN
Background and Objectives: Robotic surgical systems have rapidly become integrated into colorectal surgery practice in recent years, particularly for rectal resections, where the advantages of robotic platforms over conventional laparoscopy are more pronounced. However, as with any technological advancement, the initial high costs can be a limiting factor, leading to unequal health service access, especially in middle- and lower-income countries. Materials and Method: A narrative review was conducted with the objective of providing an overview of the escalating adoption, current training programmes, and certification process of robotic colorectal surgery in Brazil. Results: Brazil has witnessed a rapid increase in robotic platforms in recent years. Currently, there are 106 robotic systems installed nationwide. However, approximately 60% of the medical facilities which adopted robotic platforms are in the Southeast region, which is both the most populous and economically prosperous in the country. The Brazilian Society of Coloproctology recently established clear rules for the training programme and certification of colorectal surgeons in robotic surgery. The key components of the training encompass theoretical content, virtual robotic simulation, observation, assistance, and supervised procedures in colorectal surgery. Although the training parameters are well established, no colorectal surgery residency programme in Brazil has yet integrated the teaching and training of robotic surgery into its curriculum. Thus far, the training process has been led by private institutions and the industry. Conclusion: Despite the fast spread of robotic platforms across Brazil, several challenges still need to be addressed to democratise training and promote the widespread use of these platforms. It is crucial to tackle these obstacles to achieve greater integration of robotic technology in colorectal surgery throughout the country.
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Cirugía Colorrectal , Procedimientos Quirúrgicos del Sistema Digestivo , Procedimientos Quirúrgicos Robotizados , Robótica , Humanos , BrasilRESUMEN
The highly automated macromolecular crystallography beamline AMX/17-ID-1 is an undulator-based high-intensity (>5 × 1012â photonsâ s-1), micro-focus (7â µm × 5â µm), low-divergence (1â mrad × 0.35â mrad) energy-tunable (5-18â keV) beamline at the NSLS-II, Brookhaven National Laboratory, Upton, NY, USA. It is one of the three life science beamlines constructed by the NIH under the ABBIX project and it shares sector 17-ID with the FMX beamline, the frontier micro-focus macromolecular crystallography beamline. AMX saw first light in March 2016 and started general user operation in February 2017. At AMX, emphasis has been placed on high throughput, high capacity, and automation to enable data collection from the most challenging projects using an intense micro-focus beam. Here, the current state and capabilities of the beamline are reported, and the different macromolecular crystallography experiments that are routinely performed at AMX/17-ID-1 as well as some plans for the near future are presented.
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Sincrotrones , Cristalografía por Rayos X , Sustancias Macromoleculares/químicaRESUMEN
Genetically identical individuals in bacterial populations can display significant phenotypic variability. This variability can be functional, for example by allowing a fraction of stress prepared cells to survive an otherwise lethal stress. The optimal fraction of stress prepared cells depends on environmental conditions. However, how bacterial populations modulate their level of phenotypic variability remains unclear. Here we show that the alternative sigma factor σV circuit in Bacillus subtilis generates functional phenotypic variability that can be tuned by stress level, environmental history and genetic perturbations. Using single-cell time-lapse microscopy and microfluidics, we find the fraction of cells that immediately activate σV under lysozyme stress depends on stress level and on a transcriptional memory of previous stress. Iteration between model and experiment reveals that this tunability can be explained by the autoregulatory feedback structure of the sigV operon. As predicted by the model, genetic perturbations to the operon also modulate the response variability. The conserved sigma-anti-sigma autoregulation motif is thus a simple mechanism for bacterial populations to modulate their heterogeneity based on their environment.
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Regulación Bacteriana de la Expresión Génica , Factor sigma , Bacillus subtilis/genética , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Variación Biológica Poblacional , Homeostasis , Humanos , Operón/genética , Factor sigma/genética , Factor sigma/metabolismoRESUMEN
BACKGROUND : Although endoscopic vacuum therapy (EVT) has been successfully used to treat postoperative upper gastrointestinal (UGI) wall defects, its use demands special materials and several endoscopic treatment sessions. Herein, we propose a technical modification of EVT using a double tube (tube-in-tube drain) without polyurethane sponges for the drainage element. The tube-in-tube drainage device enables irrigation and application of suction. A flowchart for standardizing the management of postoperative UGI wall defects with this device is presented. METHODS : An EVT modification was made to achieve frequent fistula cleansing, with 3â% hydrogen peroxide rinsing, and the application of negative pressure. A tube-in-tube drain without polyurethane sponges can be inserted like a nasogastric tube or passed through a previously positioned surgical drain. This was a retrospective two-center observational study, with data collected from 30 consecutive patients. Technical success, clinical success, adverse events, time under therapy, interval time from procedure to fistula diagnosis and treatment start, size of transmural defect, volume of cavity, number of endoscopic treatment sessions, and mortality were reviewed. RESULTS : 30 patients with UGI wall defects were treated. The technical and clinical success rates were 100â% and 86.7â%, respectively. Three patients (10â%) had adverse events and three patients (10â%) died. The median time under therapy was of 19 days (range 1-70) and the median number of endoscopic sessions was 3 (range 1-9). CONCLUSIONS : This standardized approach and EVT modification using a tube-in-tube drain, with frequent fistula cleansing, were successful and safe in a wide variety of UGI wall defects.
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Fístula , Terapia de Presión Negativa para Heridas , Fuga Anastomótica/cirugía , Humanos , Peróxido de Hidrógeno , Terapia de Presión Negativa para Heridas/métodos , Poliuretanos , Estudios RetrospectivosRESUMEN
Natural Language Processing (NLP) can offer important tools for unlocking relevant information from clinical narratives. Although Transformer-based models can achieve remarkable results in several different NLP tasks, these models have been less used in clinical NLP, and particularly in low resource languages, of which Portuguese is one example. It is still not entirely clear whether pre-trained Transformer models are useful for clinical tasks, without further architecture engineering or particular training strategies. In this work, we propose a BERT model to assign ICD-10 codes for causes of death, by analyzing free-text descriptions in death certificates, together with the associated autopsy reports and clinical bulletins, from the Portuguese Ministry of Health. We used a novel pre-training procedure that incorporates in-domain knowledge, and also a fine-tuning method to address the class imbalance issue. Experimental results show that, in this particular clinical task that requires the processing of relatively short documents, Transformer-based models can achieve very strong results, significantly outperforming tailored approaches based on recurrent neural networks.
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Certificado de Defunción , Clasificación Internacional de Enfermedades , Portugal , Procesamiento de Lenguaje Natural , Redes Neurales de la ComputaciónRESUMEN
Two new macromolecular crystallography (MX) beamlines at the National Synchrotron Light Source II, FMX and AMX, opened for general user operation in February 2017 [Schneider et al. (2013). J. Phys. Conf. Ser. 425, 012003; Fuchs et al. (2014). J. Phys. Conf. Ser. 493, 012021; Fuchs et al. (2016). AIP Conf. Proc. SRI2015, 1741, 030006]. FMX, the micro-focusing Frontier MX beamline in sector 17-ID-2 at NSLS-II, covers a 5-30â keV photon energy range and delivers a flux of 4.0â ×â 1012â photonsâ s-1 at 1â Å into a 1â µmâ ×â 1.5â µm to 10â µmâ ×â 10â µm (Vâ ×â H) variable focus, expected to reach 5â ×â 1012â photonsâ s-1 at final storage-ring current. This flux density surpasses most MX beamlines by nearly two orders of magnitude. The high brightness and microbeam capability of FMX are focused on solving difficult crystallographic challenges. The beamline's flexible design supports a wide range of structure determination methods - serial crystallography on micrometre-sized crystals, raster optimization of diffraction from inhomogeneous crystals, high-resolution data collection from large-unit-cell crystals, room-temperature data collection for crystals that are difficult to freeze and for studying conformational dynamics, and fully automated data collection for sample-screening and ligand-binding studies. FMX's high dose rate reduces data collection times for applications like serial crystallography to minutes rather than hours. With associated sample lifetimes as short as a few milliseconds, new rapid sample-delivery methods have been implemented, such as an ultra-high-speed high-precision piezo scanner goniometer [Gao et al. (2018). J. Synchrotron Rad. 25, 1362-1370], new microcrystal-optimized micromesh well sample holders [Guo et al. (2018). IUCrJ, 5, 238-246] and highly viscous media injectors [Weierstall et al. (2014). Nat. Commun. 5, 3309]. The new beamline pushes the frontier of synchrotron crystallography and enables users to determine structures from difficult-to-crystallize targets like membrane proteins, using previously intractable crystals of a few micrometres in size, and to obtain quality structures from irregular larger crystals.
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Sincrotrones , Cristalografía , Cristalografía por Rayos X , Recolección de Datos , Sustancias Macromoleculares , ViscosidadRESUMEN
BACKGROUND AND AIM: Endoscopic submucosal dissection and transanal endoscopic microsurgery are good options for the treatment of rectal adenomas and early rectal carcinomas, but whether long-term outcomes of these procedures are comparable is not known. The aim of this study was to address this question. METHODS: A retrospective single-center study evaluating 98 consecutive procedures between June 2008 and December 2017 was performed in a tertiary cancer center. Consecutive patients who had undergone either endoscopic submucosal resection or transanal endoscopic microsurgery for rectal adenomas and early rectal carcinomas were evaluated, and long-term recurrence and complication rates were compared. RESULTS: Both groups were similar regarding sex, age, preoperative surgical risk, and en bloc resection rate (95.7% in the endoscopic and 100% in the surgical group, P = 0.81). Mean follow-up period was 37.6 months. Lesions resected endoscopically were significantly larger (68.5 mm) than those resected by transanal resection (44.5 mm), P = 0.003. Curative resections occurred in 97.2% of endoscopic resections and 85.2% of the surgical ones (P = 0.04). Comparing resections that fulfilled histologic curative criteria, there were no recurrences in the endoscopic group (out of 69 cases) and two recurrences in the transanal group (8.3% of 24 cases), P = 0.06. Late complications occurred in 12.7% of endoscopic procedures and 25.9% of surgical procedures (P = 0.13). CONCLUSIONS: In our experience, endoscopic submucosal resection seems to have advantages over transanal endoscopic microsurgery, with similar en bloc resection rate and lower rate of late complications and recurrences. Multicenter randomized controlled trials are needed to support our findings.
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Adenoma/cirugía , Carcinoma/cirugía , Resección Endoscópica de la Mucosa/métodos , Neoplasias del Recto/cirugía , Microcirugía Endoscópica Transanal/métodos , Adenoma/patología , Anciano , Carcinoma/patología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Recurrencia Local de Neoplasia/epidemiología , Recurrencia Local de Neoplasia/prevención & control , Complicaciones Posoperatorias/epidemiología , Complicaciones Posoperatorias/prevención & control , Neoplasias del Recto/patología , Estudios Retrospectivos , Factores de Tiempo , Resultado del TratamientoRESUMEN
How cells maintain their size has been extensively studied under constant conditions. In the wild, however, cells rarely experience constant environments. Here, we examine how the 24-h circadian clock and environmental cycles modulate cell size control and division timings in the cyanobacterium Synechococcus elongatus using single-cell time-lapse microscopy. Under constant light, wild-type cells follow an apparent sizer-like principle. Closer inspection reveals that the clock generates two subpopulations, with cells born in the subjective day following different division rules from cells born in subjective night. A stochastic model explains how this behavior emerges from the interaction of cell size control with the clock. We demonstrate that the clock continuously modulates the probability of cell division throughout day and night, rather than solely applying an on-off gate to division, as previously proposed. Iterating between modeling and experiments, we go on to identify an effective coupling of the division rate to time of day through the combined effects of the environment and the clock on cell division. Under naturally graded light-dark cycles, this coupling narrows the time window of cell divisions and shifts divisions away from when light levels are low and cell growth is reduced. Our analysis allows us to disentangle, and predict the effects of, the complex interactions between the environment, clock, and cell size control.
Asunto(s)
Relojes Circadianos , Synechococcus/fisiología , División Celular , Tamaño de la Célula , Relojes Circadianos/efectos de la radiación , Ecosistema , Ambiente , Luz , Modelos Biológicos , Synechococcus/citología , Synechococcus/crecimiento & desarrollo , Synechococcus/efectos de la radiaciónRESUMEN
The cyanobacterium Synechococcus elongatus possesses a circadian clock in the form of a group of proteins whose concentrations and phosphorylation states oscillate with daily periodicity under constant conditions. The circadian clock regulates the cell cycle such that the timing of the cell divisions is biased toward certain times during the circadian period, but the mechanism underlying this phenomenon remains unclear. Here, we propose a mechanism in which a protein limiting for division accumulates at a rate proportional to the cell volume growth and is modulated by the clock. This "modulated rate" model, in which the clock signal is integrated over time to affect division timing, differs fundamentally from the previously proposed "gating" concept, in which the clock is assumed to suppress divisions during a specific time window. We found that although both models can capture the single-cell statistics of division timing in S. elongatus, only the modulated rate model robustly places divisions away from darkness during changes in the environment. Moreover, within the framework of the modulated rate model, existing experiments on S. elongatus are consistent with the simple mechanism that division timing is regulated by the accumulation of a division limiting protein in a phase with genes whose activity peaks at dusk.
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Relojes Circadianos , Synechococcus , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Ritmo Circadiano , Regulación Bacteriana de la Expresión GénicaRESUMEN
We evaluate how doctors in an emergency department react to the number of patients waiting for treatment. Our outcomes reflect the time spent with the patient, the intensity of treatment, and discharge destination. Using visit-level data in a Lisbon-area hospital, we use a fixed effects model to exploit variation in the queue size while addressing endogeneity using the number of arrivals to the hospital in the previous 60 min as an instrumental variable. Furthermore, we estimate doctors' reactions separately for patients with different degrees of urgency, as measured by the Manchester triage system. Results show that doctors discharge patients more rapidly as queues become longer, and this effect is stronger for patients that do not have life-threatening conditions. We also find that the intensity of diagnosis/treatment procedures decreases when patients face longer queues, driven by the extensive margin. Finally, doctors are less likely to admit patients to inpatient care. We interpret the results in the light of the doctors' incentives literature, explaining how these agents behave in the context of a National Health Service, with no financial incentives.
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Servicio de Urgencia en Hospital/tendencias , Motivación , Alta del Paciente/estadística & datos numéricos , Médicos/estadística & datos numéricos , Listas de Espera , Humanos , Tiempo de Internación/estadística & datos numéricos , Portugal , Medicina Estatal , Factores de TiempoRESUMEN
Caprine alphaherpesvirus 1 (CpHV-1) is a worldwide pathogen of goats and is closely related to Bovine alphaherpevirus 1 (BoHV-1). We herein studied the antigenic relationships of CpHV-1 with BoHV-1 and investigated the pathogenesis of CpHV-1 in kids and calves. Monoclonal antibody reactivity revealed that CpHV-1 and BoHV-1 share immunogenic epitopes in the major envelope glycoproteins gB, gC and gD. The antigenic relationship was further demonstrated by virus-neutralizing assays, in which CpHV-1 and BoHV-1 antisera presented varied degrees of cross-neutralization against the respective heterologous viruses. Although cross-neutralization was observed between both viruses and the heterologous antisera, BoHV-1 antisera neutralized CpHV-1 with higher efficiency than CpHV-1 antisera neutralized BoHV-1. Hence, the antigenic cross-reactivity between CpHV-1 and BoHV-1 should be considered upon serologic testing of goats and cattle in regions where the two viruses co-circulate. Intranasal (IN) inoculation of CpHV-1 (WI13-46 isolate) in seven seronegative kids resulted in efficient viral replication in the respiratory tract. Additionally, mild to moderate systemic and respiratory signs were observed, including apathy, hyperthermia, nasal discharge and respiratory distress. Dexamethasone administration to the inoculated kids between days 36 and 40 pi did not result in virus shedding in nasal secretions. However, latent infection had been established, as evidenced by the detection of CpHV-1 DNA in trigeminal ganglia and olfactory bulbs of kids euthanized at day 67 pi. Contrasting with the outcome of infection in kids, IN inoculation of CpHV-1 in calves did not result in productive infection as no virus replication or shedding were detected, and the animals did not develop clinical signs nor seroconverted. The animal experiments demonstrated that CpHV-1 was able to produce respiratory disease in kids, but did not replicate to detectable levels in calves.
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Antígenos Virales/inmunología , Enfermedades de los Bovinos/patología , Enfermedades de los Bovinos/virología , Enfermedades de las Cabras/patología , Enfermedades de las Cabras/virología , Infecciones por Herpesviridae/veterinaria , Varicellovirus/inmunología , Animales , Animales Recién Nacidos , Anticuerpos Neutralizantes/sangre , Anticuerpos Antivirales/sangre , Bovinos , Reacciones Cruzadas , Epítopos/inmunología , Cabras , Infecciones por Herpesviridae/patología , Infecciones por Herpesviridae/virología , Varicellovirus/clasificaciónRESUMEN
BACKGROUND: Studies that describe metastases to the gastrointestinal (GI) tract are restricted to small case series. An increase in the frequency of this condition is expected, so it would be useful to better characterize the endoscopic aspects of metastasis to the GI tract. The aims of this study were to describe the frequency and endoscopic features of the lesions, and to analyze the survival rate after diagnosis of metastasis. METHODS: This was a retrospective, single-center, observational study, conducted between 2009 and 2017.âPatients with metastasis to the GI tract were included. RESULTS: 95 patients were included. Melanoma (25.3â%), lung (15.8â%), and breast (14.7â%) were the most frequent primary tumors. The most common endoscopic presentation was a solitary, ulcerated lesion in the gastric body. Conventional biopsy was diagnostic in 98.9â% of the cases. The mean and median survival rates were 13.3 months (95â% confidence interval [CI] 8.2â-â18.3) and 4.7 months (95â%CI 3.7â-â5.6), respectively. Palliative treatment with chemo- and/or radiotherapy after the diagnosis of the metastasis was related to a higher survival rate. CONCLUSIONS: Melanoma, lung, and breast cancer were the most common primary tumors to metastasize to the GI tract. The endoscopic features could not predict the primary site of the tumor. The finding of metastasis in the GI tract is related to the final stage of the cancer disease but patients who received palliative treatment with chemo- and/or radiotherapy after diagnosis of GI metastasis had higher survival rates.
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Neoplasias de la Mama/secundario , Endoscopía Gastrointestinal/métodos , Neoplasias Gastrointestinales/secundario , Tracto Gastrointestinal/patología , Neoplasias Pulmonares/secundario , Melanoma/secundario , Adulto , Anciano , Anciano de 80 o más Años , Brasil/epidemiología , Neoplasias de la Mama/diagnóstico , Femenino , Estudios de Seguimiento , Neoplasias Gastrointestinales/diagnóstico , Neoplasias Gastrointestinales/epidemiología , Humanos , Neoplasias Pulmonares/diagnóstico , Masculino , Melanoma/diagnóstico , Persona de Mediana Edad , Metástasis de la Neoplasia , Prevalencia , Estudios Retrospectivos , Tasa de Supervivencia/tendencias , Adulto JovenRESUMEN
BACKGROUND: Correctly predicting the depth of tumor invasion in the colorectal wall is crucial for successful endoscopic resection of superficial colorectal neoplasms. OBJECTIVE: The aim of this study was to assess the accuracy of magnifying chromoendoscopy in a Western medical center to predict the depth of invasion by the pit pattern classification in patients with colorectal neoplasms with a high risk of submucosal invasion. DESIGN: This single-center retrospective study, from a prospectively collected database, was conducted between April 2009 and June 2015. SETTINGS: The study was conducted at a single academic center. PATIENTS: Consecutive patients with colorectal neoplasms with high risk of submucosal invasion were included. These tumors were defined by large (≥20 mm) sessile polyps (nonpedunculated), laterally spreading tumors, or depressed lesions of any size. INTERVENTIONS: Patients underwent magnifying chromoendoscopy and were classified according to the Kudo pit pattern. The therapeutic decision, endoscopic or surgery, was defined by the magnification assessment. MAIN OUTCOME MEASURES: Sensitivity, specificity, and positive and negative predictive values of magnifying chromoendoscopy for assessment of these lesions were determined. RESULTS: A total of 123 lesions were included, with a mean size of 54.0 ± 37.1 mm. Preoperative magnifying chromoendoscopy with pit pattern classification had 73.3% sensitivity, 100% specificity, 100% positive predictive value, 96.4% negative predictive value, and 96.7% accuracy to predict depth of invasion and consequently to guide the appropriate treatment. Thirty-three rectal lesions were also examined by MRI, and 31 were diagnosed as T2 lesions. Twenty two (70.1%) of these lesions were diagnosed as noninvasive by magnifying colonoscopy, were treated by endoscopic resection, and met the curative criteria. LIMITATIONS: This was a single-center retrospective study with a single expert endoscopist experience. CONCLUSIONS: Magnifying chromoendoscopy is highly accurate for assessing colorectal neoplasms suspicious for submucosal invasion and can help to select the most appropriate treatment. See Video Abstract at http://links.lww.com/DCR/A920.
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Colonoscopía/métodos , Neoplasias Colorrectales , Colorantes/farmacología , Resección Endoscópica de la Mucosa , Aumento de la Imagen/métodos , Mucosa Intestinal , Anciano , Brasil , Neoplasias Colorrectales/patología , Neoplasias Colorrectales/cirugía , Resección Endoscópica de la Mucosa/efectos adversos , Resección Endoscópica de la Mucosa/métodos , Femenino , Humanos , Mucosa Intestinal/diagnóstico por imagen , Mucosa Intestinal/patología , Masculino , Invasividad Neoplásica , Estadificación de Neoplasias , Valor Predictivo de las Pruebas , Pronóstico , Estudios Retrospectivos , Sensibilidad y EspecificidadRESUMEN
Understanding the function of cellular machines requires a thorough analysis of the structural elements that underline their function. Electron microscopy (EM) has been pivotal in providing information about cellular ultrastructure, as well as macromolecular organization. Biological materials can be physically fixed by vitrification and imaged with cryo-electron tomography (cryo-ET) in a close-to-native condition. Using this technique, one can acquire three-dimensional (3D) information about the macromolecular architecture of cells, depict unique cellular states and reconstruct molecular networks. Technical advances over the last few years, such as improved sample preparation and electron detection methods, have been instrumental in obtaining data with unprecedented structural details. This presents an exciting opportunity to explore the molecular architecture of both individual cells and multicellular organisms at nanometer to subnanometer resolution. In this Commentary, we focus on the recent developments and in situ applications of cryo-ET to cell and structural biology.
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Células/ultraestructura , Microscopía por Crioelectrón/métodos , Humanos , Imagenología Tridimensional/métodosRESUMEN
The Frontier Microfocus Macromolecular Crystallography (FMX) beamline at the National Synchrotron Light Source II with its 1â µm beam size and photon flux of 3 × 1012 photonsâ s-1 at a photon energy of 12.66â keV has reached unprecedented dose rates for a structural biology beamline. The high dose rate presents a great advantage for serial microcrystallography in cutting measurement time from hours to minutes. To provide the instrumentation basis for such measurements at the full flux of the FMX beamline, a high-speed, high-precision goniometer based on a unique XYZ piezo positioner has been designed and constructed. The piezo-based goniometer is able to achieve sub-100â nm raster-scanning precision at over 10 grid-linepairsâ s-1 frequency for fly scans of a 200â µm-wide raster. The performance of the scanner in both laboratory and serial crystallography measurements up to the maximum frame rate of 750â Hz of the Eiger 16M's 4M region-of-interest mode has been verified in this work. This unprecedented experimental speed significantly reduces serial-crystallography data collection time at synchrotrons, allowing utilization of the full brightness of the emerging synchrotron radiation facilities.
RESUMEN
BACKGROUND AND AIMS: Malignant esophagorespiratory fistulas (MERFs) usually are managed by the placement of self-expandable metal stents (SEMSs) but with conflicting results. This study aimed to identify risk factors associated with clinical failure after SEMS placement for the treatment of MERFs. METHODS: This was a retrospective analysis of a prospectively maintained database used at a tertiary-care cancer hospital, with patients treated with SEMS placement for MERFs between January 2009 and February 2016. Logistic regression was used to identify predictive factors for clinical outcomes and to estimate the odds ratio (OR) and the 95% confidence interval (CI). The Kaplan-Meier method was used for survival analysis, and comparisons were made by using the log-rank test. RESULTS: A total of 71 patients (55 male, mean age 59 years) were included in the study, and 70 were considered for the final analysis (1 failed stent insertion). Clinical failure occurred in 44% of patients. An Eastern Cooperative Oncology Group (ECOG) performance status of 3 or 4 and fistula development during esophageal cancer treatment were associated with an increased risk of clinical failure. ECOG status of 3 or 4, pulmonary infection at the time of SEMS placement, and prior radiation therapy were predictive factors associated with lower overall survival. Dysphagia scores improved significantly 15 days after stent insertion. The overall stent-related adverse event rate was 30%. Stent migration and occlusion caused by tumor overgrowth were the most common adverse events. CONCLUSION: SEMS placement is a reasonable treatment option for MERFs; however, ECOG status of 3 or 4 and fistula development during esophageal cancer treatment may be independent predictors of clinical failure after stent placement.