Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 14.653
Filtrar
Mais filtros

Intervalo de ano de publicação
1.
Nature ; 614(7948): 471-478, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36792738

RESUMO

Thwaites Glacier represents 15% of the ice discharge from the West Antarctic Ice Sheet and influences a wider catchment1-3. Because it is grounded below sea level4,5, Thwaites Glacier is thought to be susceptible to runaway retreat triggered at the grounding line (GL) at which the glacier reaches the ocean6,7. Recent ice-flow acceleration2,8 and retreat of the ice front8-10 and GL11,12 indicate that ice loss will continue. The relative impacts of mechanisms underlying recent retreat are however uncertain. Here we show sustained GL retreat from at least 2011 to 2020 and resolve mechanisms of ice-shelf melt at the submetre scale. Our conclusions are based on observations of the Thwaites Eastern Ice Shelf (TEIS) from an underwater vehicle, extending from the GL to 3 km oceanward and from the ice-ocean interface to the sea floor. These observations show a rough ice base above a sea floor sloping upward towards the GL and an ocean cavity in which the warmest water exceeds 2 °C above freezing. Data closest to the ice base show that enhanced melting occurs along sloped surfaces that initiate near the GL and evolve into steep-sided terraces. This pronounced melting along steep ice faces, including in crevasses, produces stratification that suppresses melt along flat interfaces. These data imply that slope-dependent melting sculpts the ice base and acts as an important response to ocean warming.

2.
Nature ; 618(7966): 708-711, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37277615

RESUMO

Dust grains absorb half of the radiation emitted by stars throughout the history of the universe, re-emitting this energy at infrared wavelengths1-3. Polycyclic aromatic hydrocarbons (PAHs) are large organic molecules that trace millimetre-size dust grains and regulate the cooling of interstellar gas within galaxies4,5. Observations of PAH features in very distant galaxies have been difficult owing to the limited sensitivity and wavelength coverage of previous infrared telescopes6,7. Here we present James Webb Space Telescope observations that detect the 3.3 µm PAH feature in a galaxy observed less than 1.5 billion years after the Big Bang. The high equivalent width of the PAH feature indicates that star formation, rather than black hole accretion, dominates infrared emission throughout the galaxy. The light from PAH molecules, hot dust and large dust grains and stars are spatially distinct from one another, leading to order-of-magnitude variations in PAH equivalent width and ratio of PAH to total infrared luminosity across the galaxy. The spatial variations we observe suggest either a physical offset between PAHs and large dust grains or wide variations in the local ultraviolet radiation field. Our observations demonstrate that differences in emission from PAH molecules and large dust grains are a complex result of localized processes within early galaxies.

3.
Nature ; 605(7908): 139-145, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35444279

RESUMO

Cellular transformation induces phenotypically diverse populations of tumour-infiltrating T cells1-5, and immune checkpoint blockade therapies preferentially target T cells that recognize cancer cell neoantigens6,7. Yet, how other classes of tumour-infiltrating T cells contribute to cancer immunosurveillance remains elusive. Here, in a survey of T cells in mouse and human malignancies, we identified a population of αß T cell receptor (TCR)-positive FCER1G-expressing innate-like T cells with high cytotoxic potential8 (ILTCKs). These cells were broadly reactive to unmutated self-antigens, arose from distinct thymic progenitors following early encounter with cognate antigens, and were continuously replenished by thymic progenitors during tumour progression. Notably, expansion and effector differentiation of intratumoural ILTCKs depended on interleukin-15 (IL-15) expression in cancer cells, and inducible activation of IL-15 signalling in adoptively transferred ILTCK progenitors suppressed tumour growth. Thus, the antigen receptor self-reactivity, unique ontogeny, and distinct cancer cell-sensing mechanism distinguish ILTCKs from conventional cytotoxic T cells, and define a new class of tumour-elicited immune response.


Assuntos
Imunidade Inata , Interleucina-15 , Neoplasias , Animais , Diferenciação Celular , Camundongos , Neoplasias/metabolismo , Receptores de Antígenos de Linfócitos T/metabolismo , Linfócitos T Citotóxicos/metabolismo
4.
N Engl J Med ; 386(25): 2363-2376, 2022 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-35660797

RESUMO

BACKGROUND: Neoadjuvant chemotherapy and radiation followed by surgical resection of the rectum is a standard treatment for locally advanced rectal cancer. A subset of rectal cancer is caused by a deficiency in mismatch repair. Because mismatch repair-deficient colorectal cancer is responsive to programmed death 1 (PD-1) blockade in the context of metastatic disease, it was hypothesized that checkpoint blockade could be effective in patients with mismatch repair-deficient, locally advanced rectal cancer. METHODS: We initiated a prospective phase 2 study in which single-agent dostarlimab, an anti-PD-1 monoclonal antibody, was administered every 3 weeks for 6 months in patients with mismatch repair-deficient stage II or III rectal adenocarcinoma. This treatment was to be followed by standard chemoradiotherapy and surgery. Patients who had a clinical complete response after completion of dostarlimab therapy would proceed without chemoradiotherapy and surgery. The primary end points are sustained clinical complete response 12 months after completion of dostarlimab therapy or pathological complete response after completion of dostarlimab therapy with or without chemoradiotherapy and overall response to neoadjuvant dostarlimab therapy with or without chemoradiotherapy. RESULTS: A total of 12 patients have completed treatment with dostarlimab and have undergone at least 6 months of follow-up. All 12 patients (100%; 95% confidence interval, 74 to 100) had a clinical complete response, with no evidence of tumor on magnetic resonance imaging, 18F-fluorodeoxyglucose-positron-emission tomography, endoscopic evaluation, digital rectal examination, or biopsy. At the time of this report, no patients had received chemoradiotherapy or undergone surgery, and no cases of progression or recurrence had been reported during follow-up (range, 6 to 25 months). No adverse events of grade 3 or higher have been reported. CONCLUSIONS: Mismatch repair-deficient, locally advanced rectal cancer was highly sensitive to single-agent PD-1 blockade. Longer follow-up is needed to assess the duration of response. (Funded by the Simon and Eve Colin Foundation and others; ClinicalTrials.gov number, NCT04165772.).


Assuntos
Antineoplásicos , Segunda Neoplasia Primária , Neoplasias Retais , Anticorpos Monoclonais Humanizados , Antineoplásicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Quimiorradioterapia/efeitos adversos , Reparo de Erro de Pareamento de DNA , Humanos , Terapia Neoadjuvante/métodos , Estadiamento de Neoplasias , Segunda Neoplasia Primária/patologia , Receptor de Morte Celular Programada 1/efeitos dos fármacos , Estudos Prospectivos , Neoplasias Retais/genética , Neoplasias Retais/terapia , Reto/patologia , Resultado do Tratamento
5.
FASEB J ; 38(4): e23510, 2024 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-38407489

RESUMO

Heart failure (HF) is a leading cause of death and disability globally. Heritable factors and the extent and pattern of myocardial fibrosis are important determinants of outcomes in patients with HF. In a genome-wide association study of mortality in HF, we recently identified a genetic polymorphism on chromosome 5q22 associated with HF mortality. Here, we sought to study the mechanisms by which this variant may influence myocardial disease processes. We find that the risk allele is located in an enhancer motif upstream of the TSLP gene (encoding thymic stromal lymphopoietin), conferring increased binding of the transcription factor nescient helix-loop helix 1 (NHLH1) and increased TSLP expression in human heart. Further, we find that increased strain of primary human myocardial fibroblasts results in increased TSLP expression and that the TSLP receptor is expressed in myocardial mast cells in human single nuclei RNA sequence data. Finally, we show that TSLP overexpression induces increased transforming growth factor ß expression in myocardial mast cells and tissue fibrosis. Collectively, our findings based on follow-up of a human genetic finding implicate a novel pathway in myocardial tissue homeostasis and remodeling.


Assuntos
Insuficiência Cardíaca , Linfopoietina do Estroma do Timo , Humanos , Fatores de Transcrição Hélice-Alça-Hélice Básicos , Citocinas/genética , Fibroblastos , Estudo de Associação Genômica Ampla , Insuficiência Cardíaca/genética , Mastócitos , Miócitos Cardíacos
6.
J Physiol ; 2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38687681

RESUMO

Altered autonomic input to the heart plays a major role in atrial fibrillation (AF). Autonomic neurons termed ganglionated plexi (GP) are clustered on the heart surface to provide the last point of neural control of cardiac function. To date the properties of GP neurons in humans are unknown. Here we have addressed this knowledge gap in human GP neuron structure and physiology in patients with and without AF. Human right atrial GP neurons embedded in epicardial adipose tissue were excised during open heart surgery performed on both non-AF and AF patients and then characterised physiologically by whole cell patch clamp techniques. Structural analysis was also performed after fixation at both the single cell and at the entire GP levels via three-dimensional confocal imaging. Human GP neurons were found to exhibit unique properties and structural complexity with branched neurite outgrowth. Significant differences in excitability were revealed between AF and non-AF GP neurons as measured by lower current to induce action potential firing, a reduced occurrence of low action potential firing rates, decreased accommodation and increased synaptic density. Visualisation of entire GPs showed almost all neurons are cholinergic with a small proportion of noradrenergic and dual phenotype neurons. Phenotypic distribution differences occurred with AF including decreased cholinergic and dual phenotype neurons, and increased noradrenergic neurons. These data show both functional and structural differences occur between GP neurons from patients with and without AF, highlighting that cellular plasticity occurs in neural input to the heart that could alter autonomic influence on atrial function. KEY POINTS: The autonomic nervous system plays a critical role in regulating heart rhythm and the initiation of AF; however, the structural and functional properties of human autonomic neurons in the autonomic ganglionated plexi (GP) remain unknown. Here we perform the first whole cell patch clamp electrophysiological and large tissue confocal imaging analysis of these neurons from patients with and without AF. Our data show human GP neurons are functionally and structurally complex. Measurements of action potential kinetics show higher excitability in GP neurons from AF patients as measured by lower current to induce action potential firing, reduced low firing action potential rates, and decreased action potential accommodation. Confocal imaging shows increased synaptic density and noradrenergic phenotypes in patients with AF. Both functional and structural differences occur in GP neurons from patients with AF that could alter autonomic influence on atrial rhythm.

7.
Circulation ; 148(6): 459-472, 2023 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-37435755

RESUMO

BACKGROUND: Gut microbiota have been implicated in atherosclerotic disease, but their relation with subclinical coronary atherosclerosis is unclear. This study aimed to identify associations between the gut microbiome and computed tomography-based measures of coronary atherosclerosis and to explore relevant clinical correlates. METHODS: We conducted a cross-sectional study of 8973 participants (50 to 65 years of age) without overt atherosclerotic disease from the population-based SCAPIS (Swedish Cardiopulmonary Bioimage Study). Coronary atherosclerosis was measured using coronary artery calcium score and coronary computed tomography angiography. Gut microbiota species abundance and functional potential were assessed with shotgun metagenomics sequencing of fecal samples, and associations with coronary atherosclerosis were evaluated with multivariable regression models adjusted for cardiovascular risk factors. Associated species were evaluated for association with inflammatory markers, metabolites, and corresponding species in saliva. RESULTS: The mean age of the study sample was 57.4 years, and 53.7% were female. Coronary artery calcification was detected in 40.3%, and 5.4% had at least 1 stenosis with >50% occlusion. Sixty-four species were associated with coronary artery calcium score independent of cardiovascular risk factors, with the strongest associations observed for Streptococcus anginosus and Streptococcus oralis subsp oralis (P<1×10-5). Associations were largely similar across coronary computed tomography angiography-based measurements. Out of the 64 species, 19 species, including streptococci and other species commonly found in the oral cavity, were associated with high-sensitivity C-reactive protein plasma concentrations, and 16 with neutrophil counts. Gut microbial species that are commonly found in the oral cavity were negatively associated with plasma indole propionate and positively associated with plasma secondary bile acids and imidazole propionate. Five species, including 3 streptococci, correlated with the same species in saliva and were associated with worse dental health in the Malmö Offspring Dental Study. Microbial functional potential of dissimilatory nitrate reduction, anaerobic fatty acid ß-oxidation, and amino acid degradation were associated with coronary artery calcium score. CONCLUSIONS: This study provides evidence of an association of a gut microbiota composition characterized by increased abundance of Streptococcus spp and other species commonly found in the oral cavity with coronary atherosclerosis and systemic inflammation markers. Further longitudinal and experimental studies are warranted to explore the potential implications of a bacterial component in atherogenesis.


Assuntos
Aterosclerose , Doença da Artéria Coronariana , Humanos , Feminino , Pessoa de Meia-Idade , Masculino , Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/epidemiologia , Estudos Transversais , Cálcio , Aterosclerose/epidemiologia , Streptococcus
8.
Ann Surg ; 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38647132

RESUMO

OBJECTIVE: Assess the significance of enlarged lateral lymph nodes (LLN) for disease recurrence, metastasis, and organ preservation in patients with rectal cancer. BACKGROUND: Optimal treatment of rectal adenocarcinoma involving LLN is subject to debate. METHODS: A post hoc analysis of the OPRA trial, a multicenter study of patients with rectal cancer treated with total neoadjuvant therapy (TNT) followed by total mesorectal excision or watch-and-wait management. We analyzed the association of visible LLN (LLN+), LLN≥7 mm (short axis) on baseline MRI, and LLN≥4 mm on restaging MRI with recurrence, metastasis, and rectum preservation. RESULTS: At baseline, 57 out of 324 (18%) patients had LLN+. In 30 (53%) of 57 patients with LLN+ on baseline MRI, the LLN disappeared after TNT. Disease recurrence in LLN was rare (3.5% of patients with LLN+ and 0.4% of patients with LLN-). All patients with recurrence in LLN also had distant metastasis. The rate of organ preservation was significantly lower in patients with LLN≥4 mm on restaging MRI (P=0.013). We found no significant differences in rates of local recurrence or metastasis between patients with LLN+ vs. LLN- and in patients with LLN≥7 vs.<7 mm on baseline MRI. LLN dissection was performed in 3 patients; 2 of them died of distant metastasis. CONCLUSIONS: LLN involvement is not associated with disease recurrence or metastasis, but persistence of LLN≥4 mm after TNT is negatively associated with rectum preservation in patients with locally advanced rectal cancer treated with TNT. Dissection of lateral nodes likely benefits few patients.

9.
Ann Surg Oncol ; 2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38700799

RESUMO

BACKGROUND: Rectal tumors display varying degrees of response to total neoadjuvant therapy (TNT). We evaluated the performance of a convolutional neural network (CNN) in interpreting endoscopic images of either a non-complete response to TNT or local regrowth during watch-and-wait surveillance. METHODS: Endoscopic images from stage II/III rectal cancers treated with TNT from 2012 to 2020 at a single institution were retrospectively reviewed. Images were labelled as Tumor or No Tumor based on endoscopy timing (before, during, or after treatment) and the tumor's endoluminal response. A CNN was trained using ResNet-50 architecture. The area under the curve (AUC) was analyzed during training and for two test sets. The main test set included images of tumors treated with TNT. The other contained images of local regrowth. The model's performance was compared to sixteen surgeons and surgical trainees who evaluated 119 images for evidence of tumor. Fleiss' kappa was calculated by respondent experience level. RESULTS: A total of 2717 images from 288 patients were included; 1407 (51.8%) contained tumor. The AUC was 0.99, 0.98, and 0.92 for training, main test, and local regrowth test sets. The model performed on par with surgeons of all experience levels for the main test set. Interobserver agreement was good ( k = 0.71-0.81). All groups outperformed the model in identifying tumor from images of local regrowth. Interobserver agreement was fair to moderate ( k = 0.24-0.52). CONCLUSIONS: A highly accurate CNN matched the performance of colorectal surgeons in identifying a noncomplete response to TNT. However, the model demonstrated suboptimal accuracy when analyzing images of local regrowth.

10.
Dis Colon Rectum ; 67(2): 240-245, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-37815326

RESUMO

BACKGROUND: The Memorial Sloan Kettering clinical calculator for estimating the likelihood of freedom from colon cancer recurrence on the basis of clinical and molecular variables was developed at a time when testing for microsatellite instability was performed selectively, based on patient age, family history, and histologic features. Microsatellite stability was assumed if no testing was done. OBJECTIVE: This study aimed to validate the calculator in a cohort of patients who had all been tested for microsatellite instability. DESIGN: Retrospective cohort analysis. SETTINGS: Comprehensive cancer center. PATIENTS: This study included consecutive patients who underwent curative resection for stage I, II, or III colon cancer between 2017 and 2019. INTERVENTION: Universal testing of mircrosatellite phenotype in all cases. MAIN OUTCOME MEASURES: The calculator's predictive accuracy was assessed using the concordance index and a calibration plot of predicted versus actual freedom from recurrence at 3 years after surgery. For a secondary sensitivity analysis, the presence of a tumor deposit(s) (disease category N1c) was considered equivalent to one positive lymph node (category N1a). RESULTS: With a median follow-up of 32 months among survivors, the concordance index for the 745 patients in the cohort was 0.748 (95% CI, 0.693-0.801), and a plot of predicted versus observed recurrences approached the 45° diagonal, indicating good discrimination and calibration. In the secondary sensitivity analysis for tumor deposits, the concordance index was 0.755 (95% CI, 0.700-0.806). LIMITATIONS: This study was limited by its retrospective, single-institution design. CONCLUSIONS: These results, based on inclusion of actual rather than imputed microsatellite stability status and presence of tumor deposits, confirm the predictive accuracy and reliability of the calculator. See Video Abstract . VALIDACIN DE UNA CALCULADORA CLNICA QUE PREDICE LA AUSENCIA DE RECURRENCIA POSTQUIRURGICA DEL CNCER DE COLON SOBRE LA BASE DE VARIABLES MOLECULARES Y CLNICAS: ANTECEDENTES:La calculadora clínica del Memorial Sloan Kettering para la estimación de la probabilidad de ausencia de recurrencia del cáncer de colon sobre la base de variables clínicas y moleculares, se desarrolló en un momento en que las pruebas para la inestabilidad de microsatélites se realizaban de forma selectiva, basadas en la edad del paciente, los antecedentes familiares y las características histológicas. Se asumía la estabilidad micro satelital si no se realizaba ninguna prueba.OBJETIVO:El objetivo de este estudio fue validar la calculadora en una cohorte de pacientes a los que se les había realizado la prueba de inestabilidad de microsatélites.DISEÑO:Análisis de cohorte retrospectivo.AJUSTE:Centro integral de cáncer.PACIENTES:Pacientes consecutivos con cáncer de colon que fueron sometidos a resección curativa por cáncer de colon en estadios I, II o III entre los años 2017 y 2019.PRINCIPALES MEDIDAS DE RESULTADO:La precisión predictiva de la calculadora fue evaluada mediante el índice de concordancia y un gráfico de calibración de la ausencia de recurrencia predecida versus la real a los 3 años tras la cirugía. A los efectos de un análisis secundario de sensibilidad, la presencia de depósito(s) tumoral(es) (categoría de enfermedad N1c) se consideró equivalente a un ganglio linfático positivo (categoría N1a).RESULTADOS:Con una mediana de seguimiento de 32 meses entre los supervivientes, el índice de concordancia para los 745 pacientes de la cohorte fue de 0,748 (intervalo de confianza del 95 %, 0,693 a 0,801), y una gráfica de recurrencias previstas versus observadas se acercó a la diagonal de 45°, indicando una buena discriminación y calibración. En el análisis secundario de sensibilidad para depósitos tumorales, el índice de concordancia fue de 0,755 (intervalo de confianza del 95 %, 0,700 a 0,806).LIMITACIONES:Diseño retrospectivo, institución única.CONCLUSIONES:Estos resultados, basados en la inclusión real del estado de estabilidad de microsatélites en lugar de imputado y la presencia de depósitos tumorales, confirman la precisión predictiva y la confiabilidad de la calculadora. (Traducción-Dr Osvaldo Gauto ).


Assuntos
Neoplasias do Colo , Nomogramas , Humanos , Estudos Retrospectivos , Extensão Extranodal/patologia , Instabilidade de Microssatélites , Reprodutibilidade dos Testes , Neoplasias do Colo/genética , Neoplasias do Colo/cirurgia , Neoplasias do Colo/patologia , Prognóstico , Estadiamento de Neoplasias
11.
Dis Colon Rectum ; 67(6): 782-795, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38701503

RESUMO

BACKGROUND: A variety of definitions for a clinical near-complete response after neoadjuvant (chemo) radiotherapy for rectal cancer are currently used. This variety leads to inconsistency in clinical practice, long-term outcome, and trial enrollment. OBJECTIVE: The aim of this study was to reach expert-based consensus on the definition of a clinical near-complete response after (chemo) radiotherapy. DESIGN: A modified Delphi process, including a systematic review, 3 surveys, and 2 meetings, was performed with an international expert panel consisting of 7 surgeons and 4 radiologists. The surveys consisted of individual features, statements, and feature combinations (endoscopy, T2-weighted MRI, and diffusion-weighted MRI). SETTING: The modified Delphi process was performed in an online setting; all 3 surveys were completed online by the expert panel, and both meetings were hosted online. MAIN OUTCOME MEASURES: The main outcome was to reach consensus (80% or more agreement). RESULTS: The expert panel reached consensus on a 3-tier categorization of the near-complete response category based on the likelihood of the response to evolve into a clinical complete response after a longer waiting interval. The panelists agreed that a near-complete response is a temporary entity only to be used in the first 6 months after (chemo)radiotherapy. Furthermore, consensus was reached that the lymph node status should be considered when deciding on a near-complete response and that biopsies are not always needed when a near-complete response is found. No consensus was reached on whether primary staging characteristics have to be taken into account when deciding on a near-complete response. LIMITATIONS: This 3-tier subcategorization is expert-based; therefore, there is no supporting evidence for this subcategorization. Also, it is unclear whether this subcategorization can be generalized into clinical practice. CONCLUSIONS: Consensus was reached on the use of a 3-tier categorization of a near-complete response, which can be helpful in daily practice as guidance for treatment and to inform patients with a near-complete response on the likelihood of successful organ preservation. See Video Abstract. UN CONSENSO INTERNACIONAL BASADO EN EXPERTOS ACERCA DE LA DEFINICIN DE UNA RESPUESTA CLNICA CASI COMPLETA DESPUS DE QUIMIORADIOTERAPIA NEOADYUVANTE CONTRA EL CNCER DE RECTO: ANTECEDENTES:Actualmente, se utilizan una variedad de definiciones para una respuesta clínica casi completa después de quimioradioterapia neoadyuvante contra el cáncer de recto. Esta variedad resulta en inconsistencia en la práctica clínica, los resultados a largo plazo y la inscripción en ensayos.OBJETIVO:El objetivo de este estudio fue llegar a un consenso de expertos sobre la definición de una respuesta clínica casi completa después de quimioradioterapia.DISEÑO:Se realizó un proceso Delphi modificado que incluyó una revisión sistemática, 3 encuestas y 2 reuniones con un panel internacional de expertos compuesto por siete cirujanos y 4 radiólogos. Las encuestas consistieron en características individuales, declaraciones y combinaciones de características (endoscopía, T2W-MRI y DWI).AJUSTE:El proceso Delphi modificado se realizó en un entorno en línea; el panel de expertos completó las tres encuestas en línea y ambas reuniones se realizaron en línea.PRINCIPALES MEDIDAS DE RESULTADO:El resultado principal fue llegar a un consenso (≥80% de acuerdo).RESULTADOS:El panel de expertos llegó a un consenso sobre una categorización de tres niveles de la categoría de respuesta casi completa basada en la probabilidad de que la respuesta evolucione hacia una respuesta clínica completa después de un intervalo de espera más largo. Los panelistas coincidieron en que una respuesta casi completa es una entidad temporal que sólo debe utilizarse en los primeros 6 meses después de la quimioradioterapia. Además, se llegó a un consenso en que se debe considerar el estado de los nódulos linfáticos al decidir sobre una respuesta casi completa y que no siempre se necesitan biopsias cuando se encuentra una respuesta casi completa. No se llegó a un consenso sobre si se deben tener en cuenta las características primarias de estadificación al decidir una respuesta casi completa.LIMITACIONES:Esta subcategorización de 3 niveles está basada en expertos; por lo tanto, no hay evidencia que respalde esta subcategorización. Además, no está claro si esta subcategorización puede generalizarse a la práctica clínica.CONCLUSIONES:Se alcanzó consenso sobre el uso de una categorización de 3 niveles de una respuesta casi completa que puede ser útil en la práctica diaria como guía para el tratamiento y para informar a los pacientes con una respuesta casi completa sobre la probabilidad de una preservación exitosa del órgano. (Traducción - Dr. Aurian Garcia Gonzalez).


Assuntos
Consenso , Técnica Delphi , Terapia Neoadjuvante , Neoplasias Retais , Humanos , Neoplasias Retais/terapia , Neoplasias Retais/patologia , Neoplasias Retais/radioterapia , Terapia Neoadjuvante/métodos , Quimiorradioterapia/métodos , Resultado do Tratamento , Imagem de Difusão por Ressonância Magnética/métodos
12.
Dis Colon Rectum ; 67(4): 496-504, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38127627

RESUMO

BACKGROUND: Anal adenocarcinoma bears a treatment strategy unique to other anal cancers. OBJECTIVE: This study aimed to describe oncologic outcomes of total neoadjuvant therapy followed by watch-and-wait approach for anal adenocarcinoma. DESIGN: Retrospective analysis. SETTINGS: This study was conducted at a comprehensive cancer center. PATIENTS: Patients with anal adenocarcinoma treated between 2004 and 2019 were selected. INTERVENTIONS: Fifty-four patients received neoadjuvant therapy and were divided into 2 groups according to their treatment strategy: total neoadjuvant therapy versus single neoadjuvant modality therapy. MAIN OUTCOME MEASURES: Organ preservation, tumor regrowth, local failure, distant metastasis rates, recurrence-free survival, and overall survival. RESULTS: This study included 70 patients with anal adenocarcinoma. Fifty-four patients (77%) received neoadjuvant therapy, of whom 30 (42%) received total neoadjuvant therapy and 24 (34%) received single neoadjuvant modality. Twenty-three (33%) patients achieved complete clinical response and were managed by watch-and-wait approach. The proportion of patients able to continue to watch-and-wait approach was higher after receiving total neoadjuvant therapy (60%) compared with single neoadjuvant modality therapy (20%; p = 0.004). A tumor regrowth rate of 22% was observed in the total neoadjuvant therapy group. The 5-year overall survival rate was 70% (95% CI, 59%-83%), including 61% (95% CI, 42%-88%) for the total neoadjuvant therapy and 65% (95% CI, 48%-88%) for the single neoadjuvant modality groups. Colostomy was avoided in 50% of patients who received total neoadjuvant therapy and 83% of watch-and-wait patients. Five-year recurrence-free survival rates of 55% (95% CI, 39%-79%) and 30% (95% CI, 15%-58%) were observed in the total neoadjuvant therapy and single neoadjuvant modality groups. LIMITATIONS: Retrospective nature. CONCLUSIONS: This is the first report in the literature describing the safety and feasibility of nonoperative management for anal adenocarcinoma. Anal adenocarcinoma treated with total neoadjuvant therapy and nonoperative management achieve regrowth rates comparable to those observed in rectal cancer, with oncologic outcomes similar to those of traditional treatment strategies. See Video Abstract . ADENOCARCINOMA ANAL TRATADO EN LA ERA DE LA TERAPIA NEOADYUVANTE TOTAL Y EL TRATAMIENTO NO QUIRRGICO: ANTECEDENTES:El adenocarcinoma anal conlleva una estrategia de tratamiento único para otros cánceres anales.OBJETIVO:Describir los resultados oncológicos de la terapia neoadyuvante total seguida de observar y esperar en adenocarcinoma anal.DISEÑO:Análisis retrospectivo.AJUSTE:Este estudio se llevó a cabo en un centro oncológico integral.PACIENTES:Se seleccionaron pacientes con adenocarcinoma anal tratados entre 2004-2019.INTERVENCIONES:Cincuenta y cuatro pacientes recibieron terapia neoadyuvante y se dividieron en dos grupos según su estrategia de tratamiento: terapia neoadyuvante total versus terapia de modalidad neoadyuvante única.PRINCIPALES MEDIDAS DE RESULTADO:Preservación de órganos, recurrencia tumoral, falla local, tasas de metástasis a distancia, libre de recurrencia y supervivencia general.RESULTADOS:El estudio incluyó a 70 pacientes con adenocarcinoma anal. Cincuenta y cuatro pacientes (77%) recibieron terapia neoadyuvante, de los cuales 30 (42%) recibieron terapia neoadyuvante total y 24 (34%) recibieron modalidad neoadyuvante única. Veintitrés (33%) pacientes presentaron una respuesta clínica completa y fueron tratados con vigilancia y espera. La proporción de pacientes capaces de continuar en observar y esperar fue mayor después de recibir terapia neoadyuvante total (60%) en comparación con la terapia de modalidad neoadyuvante única (20%) ( p = 0,004). Se observó una tasa de recurrencia tumoral del 22% en el grupo de terapia neoadyuvante total. La tasa de supervivencia general a 5 años fue del 70% (IC95% 59%-83 %), incluido el 61% (IC95% 42%-88%) para la terapia neoadyuvante total y el 65% (IC95% 48%-88%) para grupos de modalidad neoadyuvante única. Se evitó la colostomía en el 50% de los pacientes que recibieron terapia neoadyuvante total y el 83% de los pacientes en observar y esperar. Se observaron tasas de supervivencia libre de recurrencia a cinco años del 55% (IC95% 39%-79%) y del 30% (IC95% 15%-58%) en los grupos de terapia neoadyuvante total y modalidad neoadyuvante única, respectivamente.LIMITACIONES:Diseño retrospectivo.CONCLUSIONES:Este es el primer informe en la literatura que describe la seguridad y viabilidad del tratamiento no quirúrgico del adenocarcinoma anal. El adenocarcinoma anal tratado con terapia neoadyuvante total y manejo no quirúrgico logra tasas de recurrencia comparables a las observadas en el cáncer de recto, con resultados oncológicos similares a las estrategias de tratamientos tradicionales. (Traducción-Dr. Fidel Ruiz Healy ).


Assuntos
Adenocarcinoma , Neoplasias do Ânus , Neoplasias Retais , Humanos , Estudos Retrospectivos , Terapia Neoadjuvante , Conduta Expectante , Neoplasias Retais/patologia , Neoplasias do Ânus/terapia , Neoplasias do Ânus/patologia , Quimiorradioterapia , Adenocarcinoma/patologia , Recidiva Local de Neoplasia/terapia , Recidiva Local de Neoplasia/tratamento farmacológico , Resultado do Tratamento , Estadiamento de Neoplasias
13.
J Int Neuropsychol Soc ; 30(3): 199-208, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37646336

RESUMO

OBJECTIVE: Higher cardiorespiratory fitness (CRF) induces neuroprotective effects in the hippocampus, a key brain region for memory and learning. We investigated the association between CRF and functional connectivity (FC) of the hippocampus in healthy young adults. We also examined the association between hippocampal FC and neurocognitive function. Lastly, we tested whether hippocampal FC mediates the association between 2-Min Walk Test (2MWT) and neurocognitive function. METHODS: 913 young adults (28.7 ± 3.7 years) from the Human Connectome Project were included in the analyses. The 2MWT performance result was used as a proxy for cardiovascular endurance. Fluid and crystalized composite neurocognitive scores were used to assess cognition. Resting-state functional MRI data were processed to measure hippocampal FC. Linear regression was used to examine the association between 2MWT, hippocampal FC, and neurocognitive outcomes after controlling for age, sex, years of education, body mass index, systolic blood pressure, and gait speed. RESULTS: Better 2MWT performance was associated with greater FC between the anterior hippocampus and right posterior cingulate and left middle temporal gyrus. No associations between 2MWT and posterior hippocampal FC, whole hippocampal FC, and caudate FC (control region) were observed. Greater anterior hippocampal FC was associated with better crystalized cognition scores. Lastly, greater FC between the anterior hippocampus and right posterior cingulate mediated the association between better 2MWT scores and higher crystalized cognition scores. CONCLUSIONS: Anterior hippocampal FC may be one underlying neurophysiological mechanism that promotes the association between 2MWT performance and crystalized composite cognitive function in healthy young adults.


Assuntos
Aptidão Cardiorrespiratória , Humanos , Adulto Jovem , Aptidão Cardiorrespiratória/fisiologia , Hipocampo , Cognição/fisiologia , Lobo Temporal , Encéfalo , Imageamento por Ressonância Magnética
14.
Nanotechnology ; 35(27)2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38579686

RESUMO

Perpendicular magnetic tunnel junction (pMTJ)-based true-random number generators (RNGs) can consume orders of magnitude less energy per bit than CMOS pseudo-RNGs. Here, we numerically investigate with a macrospin Landau-Lifshitz-Gilbert equation solver the use of pMTJs driven by spin-orbit torque to directly sample numbers from arbitrary probability distributions with the help of a tunable probability tree. The tree operates by dynamically biasing sequences of pMTJ relaxation events, called 'coinflips', via an additional applied spin-transfer-torque current. Specifically, using a single, ideal pMTJ device we successfully draw integer samples on the interval [0, 255] from an exponential distribution based onp-value distribution analysis. In order to investigate device-to-device variations, the thermal stability of the pMTJs are varied based on manufactured device data. It is found that while repeatedly using a varied device inhibits ability to recover the probability distribution, the device variations average out when considering the entire set of devices as a 'bucket' to agnostically draw random numbers from. Further, it is noted that the device variations most significantly impact the highest level of the probability tree, with diminishing errors at lower levels. The devices are then used to draw both uniformly and exponentially distributed numbers for the Monte Carlo computation of a problem from particle transport, showing excellent data fit with the analytical solution. Finally, the devices are benchmarked against CMOS and memristor RNGs, showing faster bit generation and significantly lower energy use.

15.
Int J Colorectal Dis ; 39(1): 75, 2024 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-38780794

RESUMO

BACKGROUND: Palmar-plantar erythrodysesthesia (PPE) is a slowly developing cutaneous reaction commonly experienced by patients treated with fluoropyrimidines. While erythrodysesthesia normally presents in a palmar-plantar distribution, it can also present with genital involvement, but this presentation is likely underreported and incorrectly attributed to an acute reaction from radiation therapy. This article aims to define erythrodysesthesia of the penis and scrotum as a rare but significant side effect of capecitabine. CASE PRESENTATION: We identified five cases of moderate to severe penis and scrotal erythrodysesthesia over a 2-year period at a large tertiary cancer center, representing an estimated incidence of 3.6% among male patients with rectal cancer who were treated with fluoropyrimidine-based chemoradiation within our institution. CONCLUSIONS: Improved understanding of erythrodysesthesia involving the penis and scrotum can facilitate early identification and treatment of symptoms, and possibly prevent the discontinuation or delay of cancer treatment in patients treated with capecitabine and similar drugs. These clinical advances would improve and prolong patient quality of life during cancer treatment and prevent complications that result in hospitalization.


Assuntos
Capecitabina , Quimiorradioterapia , Neoplasias Retais , Escroto , Humanos , Masculino , Neoplasias Retais/terapia , Neoplasias Retais/tratamento farmacológico , Pessoa de Meia-Idade , Escroto/patologia , Idoso , Quimiorradioterapia/efeitos adversos , Capecitabina/efeitos adversos , Pênis/patologia , Pênis/efeitos da radiação
16.
Ultrasound Obstet Gynecol ; 63(4): 481-488, 2024 04.
Artigo em Inglês | MEDLINE | ID: mdl-37820067

RESUMO

OBJECTIVE: Placental vascular reactivity (PlVR) indicates the ability of the placental vasculature to match blood supply to fetal demand. Many pregnancy disorders alter the characteristics of PlVR, resulting in suboptimal oxygen delivery, although current understanding is limited by the lack of non-invasive, repeatable methods to measure PlVR in utero. Our objective was to quantify PlVR by measuring the placental response to transient changes in maternal carbon dioxide (CO2) using blood-oxygen-level-dependent (BOLD) magnetic resonance imaging (MRI). We hypothesized that PlVR will increase with gestational age to meet the changing demands of a growing fetus, and that PlVR will be driven by a maternal response to changes in CO2 concentration. METHODS: This was a cross-sectional study of 35 women with a healthy singleton pregnancy, of whom 31 were included in the analysis. The median gestational age was 32.6 (range, 22.6-38.4) weeks. Pregnant women were instructed to follow audiovisual breathing cues during a MRI scan. Maternal end-tidal CO2 (EtCO2) was measured concurrently with resting placental BOLD MRI for a total of 7-8 min. Preprocessing of magnetic resonance images consisted of manual delineation of placental anatomy and motion correction. In each placental voxel, vascular reactivity was computed using a coherence-weighted general linear model between MRI signal and EtCO2 stimulus. Global PlVR was computed as the mean of voxel-wise PlVR values across the placenta. RESULTS: PlVR, quantified by the placental response to induced, transient changes in maternal CO2, was consistently measured in utero using BOLD MRI. PlVR increased non-linearly with advancing gestational age (P < 0.001) and was higher on the fetal side of the placenta. PlVR was associated positively with fetal brain volume after accounting for gestational age. PlVR did not show any significant associations with maternal characteristics. CONCLUSIONS: We present, for the first time, a non-invasive paradigm to quantify PlVR in ongoing human pregnancies without the use of exogenous gases or contrast agents. Our findings suggest that PlVR is driven by a fetal response to changes in maternal CO2. Ease of translation to the clinical setting makes PlVR a promising biomarker for the identification and management of high-risk pregnancies. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.


Assuntos
Placenta , Complicações na Gravidez , Gravidez , Feminino , Humanos , Lactente , Placenta/irrigação sanguínea , Estudos Transversais , Dióxido de Carbono , Imageamento por Ressonância Magnética/métodos , Oxigênio
17.
Colorectal Dis ; 26(3): 459-465, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38263577

RESUMO

AIM: Tumour deposits are focal aggregates of cancer cells in pericolic fat and mesentery, distinct from vessels, nerves and lymphatics. Their presence upstages lymph node negative patients but is ignored in lymph node positive patients. We investigated the clinicopathological factors associated with tumour deposits and their impact on recurrence in lymph node positive and negative patients. METHOD: Clinicopathological variables were collected from the medical records of patients with Stage I-III colon cancer who underwent resection in 2017-2019. Pathology was reviewed by a gastrointestinal pathologist. Patients with rectal cancer, metastasis, and concurrent malignancy were excluded. RESULTS: Tumour deposits were noted in 69 (9%) of 770 patients. They were associated with the presence of lymph node metastasis, advanced T category, poorly differentiated tumours, microsatellite stable subtype and lymphovascular and perineural invasion (p < 0.05). The presence of tumour deposits (hazard ratio 2.48, 95% CI 1.49-4.10) and of lymph node metastasis (hazard ratio 3.04, 95% CI 1.72-5.37) were independently associated with decreased time to recurrence. There was a weak correlation (0.27) between the number of tumour deposits and the number of positive lymph nodes. CONCLUSION: Tumour deposits are associated with more advanced disease and high-risk pathological features. The presence of tumour deposits and lymph node metastasis were found to be independent risk factors for decreased time to recurrence. A patient with both lymph node metastasis and tumour deposits is more than twice as likely to have recurrence compared with a patient with only lymph node metastasis. Tumour deposits independently predict recurrence and should not be ignored in lymph node positive patients.


Assuntos
Neoplasias do Colo , Extensão Extranodal , Humanos , Metástase Linfática/patologia , Extensão Extranodal/patologia , Prognóstico , Estudos Retrospectivos , Neoplasias do Colo/cirurgia , Neoplasias do Colo/patologia , Linfonodos/cirurgia , Linfonodos/patologia , Estadiamento de Neoplasias
19.
Anaesthesia ; 79(6): 583-592, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38369586

RESUMO

The 7th National Audit Project of the Royal College of Anaesthetists studied peri-operative cardiac arrest. An activity survey estimated UK paediatric anaesthesia annual caseload as 390,000 cases, 14% of the UK total. Paediatric peri-operative cardiac arrests accounted for 104 (12%) reports giving an incidence of 3 in 10,000 anaesthetics (95%CI 2.2-3.3 per 10,000). The incidence of peri-operative cardiac arrest was highest in neonates (27, 26%), infants (36, 35%) and children with congenital heart disease (44, 42%) and most reports were from tertiary centres (88, 85%). Frequent precipitants of cardiac arrest in non-cardiac surgery included: severe hypoxaemia (20, 22%); bradycardia (10, 11%); and major haemorrhage (9, 8%). Cardiac tamponade and isolated severe hypotension featured prominently as causes of cardiac arrest in children undergoing cardiac surgery or cardiological procedures. Themes identified at review included: inappropriate choices and doses of anaesthetic drugs for intravenous induction; bradycardias associated with high concentrations of volatile anaesthetic agent or airway manipulation; use of atropine in the place of adrenaline; and inadequate monitoring. Overall quality of care was judged by the panel to be good in 64 (62%) cases, which compares favourably with adults (371, 52%). The study provides insight into paediatric anaesthetic practice, complications and peri-operative cardiac arrest.


Assuntos
Parada Cardíaca , Auditoria Médica , Humanos , Parada Cardíaca/epidemiologia , Criança , Lactente , Recém-Nascido , Reino Unido/epidemiologia , Pré-Escolar , Complicações Pós-Operatórias/epidemiologia , Anestesia/efeitos adversos , Assistência Perioperatória/métodos , Adolescente
20.
Anaesthesia ; 79(1): 43-53, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37944508

RESUMO

Complications and critical incidents arising during anaesthesia due to patient, surgical or anaesthetic factors, may cause harm themselves or progress to more severe events, including cardiac arrest or death. As part of the 7th National Audit Project of the Royal College of Anaesthetists, we studied a prospective national cohort of unselected patients. Anaesthetists recorded anonymous details of all cases undertaken over 4 days at their site through an online survey. Of 416 hospital sites invited to participate, 352 (85%) completed the survey. Among 24,172 cases, 1922 discrete potentially serious complications were reported during 1337 (6%) cases. Obstetric cases had a high reported major haemorrhage rate and were excluded from further analysis. Of 20,996 non-obstetric cases, 1705 complications were reported during 1150 (5%) cases. Circulatory events accounted for most complications (616, 36%), followed by airway (418, 25%), metabolic (264, 15%), breathing (259, 15%), and neurological (41, 2%) events. A single complication was reported in 851 (4%) cases, two complications in 166 (1%) cases and three or more complications in 133 (1%) cases. In non-obstetric elective surgery, all complications were 'uncommon' (10-100 per 10,000 cases). Emergency (urgent and immediate priority) surgery accounted for 3454 (16%) of non-obstetric cases but 714 (42%) of complications with severe hypotension, major haemorrhage, severe arrhythmias, septic shock, significant acidosis and electrolyte disturbances all being 'common' (100-1000 per 10,000 cases). Based on univariate analysis, complications were associated with: younger age; higher ASA physical status; male sex; increased frailty; urgency and extent of surgery; day of the week; and time of day. These data represent the rates of potentially serious complications during routine anaesthesia care and may be valuable for risk assessment and patient consent.


Assuntos
Anestesia , Anestésicos , Feminino , Gravidez , Humanos , Masculino , Incidência , Estudos Prospectivos , Anestesia/efeitos adversos , Hemorragia , Reino Unido/epidemiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA