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1.
J Agric Food Chem ; 68(5): 1468-1479, 2020 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-31945291

RESUMEN

In this study, sample processing of bulk commodities using an efficient one-step comminution procedure with liquid nitrogen (LN2) was devised and assessed in the analysis of pesticide residues in fruits and vegetables. LN2 was added to the fresh samples from a tank by opening a valve, and the standard food chopper was kept in a laboratory hood to reduce safety risks. Test portions of four replicates each of 0.25, 0.5, 1, 2, 5, 10, and 15 g were taken from eight fruits and vegetables (tomato, squash, broccoli, apple, grape, peach, green bean, and cucumber) individually comminuted with LN2. For comparison without comminution, similar test portions of a reconstituted freeze-dried certified reference material of pesticides in cucumber were also analyzed by the same method. More than 100 pesticides were monitored by both ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) and instrument top sample preparation (ITSP) + fast low-pressure gas chromatography-tandem mass spectrometry (LPGC-MS/MS). A new version of QuEChERS-based sample preparation was followed, in which 5 mL of 4:1 (v/v) acetonitrile/water per gram of sample is used for extraction and 200 µL of initial extract is quickly evaporated, reconstituted in water, and ultracentrifuged for UHPLC-MS/MS analysis. For ITSP+LPGC-MS/MS, another portion of the initial extract undergoes salt-out partitioning with 4:1 (w/w) anhydrous MgSO4/NaCl and the upper layer extract is transferred to an autosampler vial for automated cleanup and analysis in parallel. Quality control spikes were made during the comminution, extraction, cleanup, and analysis steps to isolate and estimate the individual and overall measurement uncertainties of the approach. The recommended test portion size is 2 g for routine monitoring by this approach, but results demonstrated that subsamples as low as 0.5 g typically gave overall biases and relative standard deviations of <10% for nearly all pesticides, commodities, and methods, which is 3-5% lower than previously evaluated sample processing and analytical methods. This approach can be used to improve data quality, laboratory efficiency, and sample throughput in routine monitoring programs for regulatory, risk assessment, and other purposes.


Asunto(s)
Contaminación de Alimentos/análisis , Frutas/química , Ensayos Analíticos de Alto Rendimiento/métodos , Nitrógeno/química , Residuos de Plaguicidas/análisis , Verduras/química , Cromatografía Líquida de Alta Presión , Control de Calidad , Tamaño de la Muestra , Espectrometría de Masas en Tándem
3.
Nan Fang Yi Ke Da Xue Xue Bao ; 39(10): 1200-1206, 2019 Oct 30.
Artículo en Chino | MEDLINE | ID: mdl-31801710

RESUMEN

OBJECTIVE: We propose a strategy for identifying subgroups with the treatment effect from the survival data of a randomized clinical trial based on accelerated failure time (AFT) model. METHODS: We applied adaptive elastic net to the AFT model (designated as the penalized model) and identified the candidate covariates based on covariate-treatment interactions. To classify the patient subgroups, we utilized a likelihood-based change-point algorithm to determine the threshold cutoff point. A two-stage adaptive design was adopted to verify if the treatment effect existed within the identified subgroups. RESULTS: The penalized model with the main effect of the covariates considerably outperformed the univariate model without the main effect for the trial data with a small sample size, a high censoring rate, a small subgroup size, or a sample size that did not exceed the number of covariates; in other scenarios, the latter model showed better performances. Compared with the traditional design, the adaptive design improved the power for detecting the treatment effect where subgroup effect exists with a well-controlled type Ⅰ error. CONCLUSIONS: The penalized AFT model with the main effect of the covariates has advantages in subgroup identification from the survival data of clinical trials. Compared with the traditional design, the two-stage adaptive design has better performance in evaluation of the treatment effect when a subgroup effect exists.


Asunto(s)
Algoritmos , Proyectos de Investigación , Tamaño de la Muestra , Humanos , Funciones de Verosimilitud , Ensayos Clínicos Controlados Aleatorios como Asunto , Tiempo
4.
BMC Bioinformatics ; 20(1): 566, 2019 Nov 12.
Artículo en Inglés | MEDLINE | ID: mdl-31718533

RESUMEN

BACKGROUND: In single cell DNA and RNA sequencing experiments, the number of cells to sequence must be decided before running an experiment, and afterwards, it is necessary to decide whether sufficient cells were sampled. These questions can be addressed by calculating the probability of sampling at least a defined number of cells from each subpopulation (cell type or cancer clone). RESULTS: We developed an interactive web application called SCOPIT (Single-Cell One-sided Probability Interactive Tool), which calculates the required probabilities using a multinomial distribution (www.navinlab.com/SCOPIT). In addition, we created an R package called pmultinom for scripting these calculations. CONCLUSIONS: Our tool for fast multinomial calculations provide a simple and intuitive procedure for prospectively planning single-cell experiments or retrospectively evaluating if sufficient numbers of cells have been sequenced. The web application can be accessed at navinlab.com/SCOPIT.


Asunto(s)
Análisis de Secuencia de ADN/métodos , Análisis de Secuencia de ARN/métodos , Análisis de la Célula Individual/métodos , Programas Informáticos , Humanos , Estudios Retrospectivos , Tamaño de la Muestra
5.
Presse Med ; 48(10): e273-e283, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31734048

RESUMEN

OBJECTIVES: Self-medication for alleviating pain is very prevalent in most countries. While safe self-medication is supposed to be dependent on both patient's behaviour and pharmacist's counselling, little is known about the context of the delivery of analgesics available without prescription. The primary objective of the study was to define sociodemographic profiles and behaviours of patients seeking non-prescribed analgesics in French community pharmacies. Secondary objectives included the assessment of pharmacist management and identification of risk-associated patients. METHODS: This is a cross-sectional, national and multicentre study, including adults who asked for a prescription-free medication for acute or chronic physical pain. Information was collected through separate patient and healthcare professional (HCP) questionnaires. RESULTS: The analysis was based on 1215 and 1271 patient and HCP questionnaires, respectively, collected from 164 pharmacies. The patient population consisted in women and men (ratio 6:4), mainly (71%) under 60 years old. Headaches, rheumatologic and musculoskeletal pains were the most frequent reasons for getting analgesics, with a median pain intensity of 6 on a scale graded from 0 (no pain) to 10 (intolerable pain). The main reasons guiding self-medication were time saving, a well-known pain and a well-known product. The mean time allocated to delivery was 4.7minutes. Indications, dose and posology were almost systematically addressed by the pharmacy staff, while contra-indications, drug-drug interaction or safety were mentioned in around two-third of cases. The proportion of patients identified at risks due to an inappropriate context of self-medication was 15.5%. DISCUSSION AND CONCLUSIONS: This study shows a great heterogeneity of the population asking for non-prescribed analgesics in French community pharmacies. While pharmacists were able to identify patients at risks, a significant part may have 'slipped through the net'. The results support further studies to better define patient care pathway and optimize pharmacist-led medication.


Asunto(s)
Dolor Agudo/tratamiento farmacológico , Analgésicos/uso terapéutico , Dolor Crónico/tratamiento farmacológico , Medicamentos sin Prescripción/uso terapéutico , Farmacéuticos , Automedicación , Adulto , Factores de Edad , Anciano , Estudios Transversales , Femenino , Francia , Encuestas de Atención de la Salud , Estado de Salud , Humanos , Masculino , Persona de Mediana Edad , Dimensión del Dolor , Farmacias/estadística & datos numéricos , Tamaño de la Muestra , Factores Sexuales , Factores Socioeconómicos
6.
Dis Colon Rectum ; 62(12): 1494-1504, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-31725582

RESUMEN

BACKGROUND: Primary sclerosing cholangitis is a classical extraintestinal manifestation in patients with ulcerative colitis. However, the impact of primary sclerosing cholangitis on the disease course is incompletely understood. OBJECTIVE: This study aimed to assess the impact of primary sclerosing cholangitis on disease phenotype and its course in patients with ulcerative colitis. DESIGN: This is a retrospective study with 3:1 matched cohorts. SETTINGS: Tertiary care center's electronic database was used for data analysis from 2000 and 2018. PATIENTS: Of 782 patients with ulcerative colitis, 77 patients who had coincident primary sclerosing cholangitis were included. MAIN OUTCOME MEASURES: The primary outcomes evaluated were disease characteristics including colonic disease activity, temporal change of disease course, colorectal neoplasia, and colectomy rates. RESULTS: Disease activity during acute flares, assessed by the complete Mayo score, was significantly lower in patients with primary sclerosing cholangitis (6.2 vs 7.3; p < 0.001). In addition, disease activity in patients with primary sclerosing cholangitis was decreased, especially within the first 10 years after disease onset, and biological therapy with anti-tumor necrosis factor and anti-integrin agents was commenced less frequently (22% vs 35%; p = 0.043) and later (10-year risk: 17.4% vs 27.8%; p = 0.034). Patients with primary sclerosing cholangitis were younger at colitis diagnosis (23.3 vs 29.3 years; p < 0.001) and had more extensive disease (75% vs 46%; p < 0.001). Colorectal cancer was more frequently detected in patients with coincident primary sclerosing cholangitis (6/77 vs 16/705; p = 0.016). Colectomy rates did not differ between both groups (14.3% vs 14.5%; p = 0.56). In contrast, patients with ulcerative colitis had to undergo surgery more frequently because of therapy-refractant inflammation, whereas surgery due to neoplasia development was increased in patients with coincident primary sclerosing cholangitis (p = 0.013). LIMITATIONS: The study was limited by its retrospective design. CONCLUSION: Patients who have ulcerative colitis with coincident primary sclerosing cholangitis develop a distinct disease course characterized by an earlier disease onset and lower disease activity, but more frequent extensive disease manifestation and higher risk for colorectal cancer. See Video Abstract at http://links.lww.com/DCR/B45. FENOTIPO DE ENFERMEDAD DISTINTIVO DE LA COLITIS ULCERATIVA EN PACIENTES CON COLANGITIS ESCLEROSANTE PRIMARIA CONCOMITANTE: EVIDENCIA DE UN ESTUDIO RETROSPECTIVO GRANDE CON COHORTES EMPAREJADAS: La colangitis esclerosante primaria es una manifestación extraintestinal clásica en pacientes con colitis ulcerativa. Sin embargo, el impacto de la colangitis esclerosante primaria en el curso de la enfermedad no es comprendido completamente.Evaluar el impacto de la colangitis esclerosante primaria en el fenotipo y curso de la enfermedad en pacientes con colitis ulcerativa.Este es un estudio retrospectivo con cohortes emparejadas 3:1.La base de datos electrónica de un centro de atención terciaria se utilizó para el análisis de datos de 2000 a 2018.782 pacientes con colitis ulcerativa, 77 padecían colangitis esclerosante primaria concomitante y fueron incluidos.Se evaluaron las características de la enfermedad, incluida la actividad de enfermedad colónica, el cambio temporal del curso de la enfermedad, la neoplasia colorrectal y las tasas de colectomía.La actividad de la enfermedad durante los brotes agudos, evaluada por la puntuación completa de Mayo, fue significativamente menor en pacientes con colangitis esclerosante primaria (6.2 vs 7.3; p < 0.001). Además, la actividad de la enfermedad en pacientes con colangitis esclerosante primaria se redujo especialmente en los primeros 10 años después del inicio de la enfermedad, y la terapia biológica con agentes anti-TNF y anti-integrina se inició con menos frecuencia (22% vs 35%; p = 0.043) y más tarde (riesgo a 10 años: 17.4% vs 27.8%; p = 0.034). Los pacientes con colangitis esclerosante primaria eran más jóvenes en el momento del diagnóstico de colitis (23.3 vs 29.3 años; p < 0.001) y tenían enfermedad más extensa (75% vs 46%; p < 0.001). El cáncer colorrectal se detectó con mayor frecuencia en pacientes con colangitis esclerosante primaria concomitante (6/77 vs 16/705; p = 0.016). Las tasas de colectomía no fueron diferentes entre ambos grupos (14.3% vs 14.5%; p = 0.56). En contraste, los pacientes con colitis ulcerativa tuvieron que someterse a cirugía con mayor frecuencia debido a inflamación refractaria a la terapia, mientras que el desarrollo de neoplasia se incrementó en pacientes con colangitis esclerosante primaria concomitante (p = 0.013).El estudio estuvo limitado por su diseño retrospectivo.Los pacientes con colitis ulcerativa con colangitis esclerosante primaria concomitante desarrollan un curso de enfermedad distintivo caracterizado por un inicio temprano de la enfermedad y una menor actividad de la enfermedad, pero con manifestación de enfermedad extensa más frecuente y un mayor riesgo de cáncer colorrectal. Vea el resumen en video en http://links.lww.com/DCR/B45.


Asunto(s)
Colangitis Esclerosante/epidemiología , Colectomía/estadística & datos numéricos , Colitis Ulcerosa/patología , Neoplasias Colorrectales/epidemiología , Neoplasias Colorrectales/cirugía , Adolescente , Adulto , Colangitis Esclerosante/patología , Colitis Ulcerosa/complicaciones , Colitis Ulcerosa/tratamiento farmacológico , Neoplasias Colorrectales/etiología , Comorbilidad , Progresión de la Enfermedad , Femenino , Humanos , Masculino , Fenotipo , Estudios Retrospectivos , Tamaño de la Muestra , Índice de Severidad de la Enfermedad , Atención Terciaria de Salud , Adulto Joven
7.
Nature ; 575(7781): 137-146, 2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-31695204

RESUMEN

The goal of sex and gender analysis is to promote rigorous, reproducible and responsible science. Incorporating sex and gender analysis into experimental design has enabled advancements across many disciplines, such as improved treatment of heart disease and insights into the societal impact of algorithmic bias. Here we discuss the potential for sex and gender analysis to foster scientific discovery, improve experimental efficiency and enable social equality. We provide a roadmap for sex and gender analysis across scientific disciplines and call on researchers, funding agencies, peer-reviewed journals and universities to coordinate efforts to implement robust methods of sex and gender analysis.


Asunto(s)
Ingeniería/métodos , Ingeniería/normas , Proyectos de Investigación/normas , Proyectos de Investigación/tendencias , Ciencia/métodos , Ciencia/normas , Caracteres Sexuales , Factores Sexuales , Animales , Inteligencia Artificial , Femenino , Humanos , Masculino , Terapia Molecular Dirigida , Reproducibilidad de los Resultados , Tamaño de la Muestra
8.
Medicine (Baltimore) ; 98(45): e17804, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31702633

RESUMEN

BACKGROUND: Ankylosing spondylitis (AS) is one of the most common chronic inflammatory disorders affecting the sacroiliac joints, spine, and peripheral joints. Apart from HLA-B27, the LMP2 gene has been shown to play a role in the pathogenesis of AS as well as AAU in AS. However, genetic associations between LMP2 CfoI polymorphism and AS and AAU were inconclusive. We aimed to investigate the correlation of LMP2 CfoI polymorphism and AS and AAU using meta-analysis. METHODS: An exhaustive search was conducted using the PubMed, Embase, Cochrane Library, and Chinese National Knowledge Infrastructure (CNKI) electronic databases. The strength association was assessed by crude ORs with 95% CI. RESULTS: Eight eligible records with 449 AS patients and 317 healthy controls were included in the present study. The allelic model of the LMP2 CfoI polymorphism is associated with AS risk (OR = 0.60, 95%CI = [0.32, 1.11], P = .003). A stratified analysis based on ethnicity has shown that the allelic model of LMP2 CfoI was associated with AS in the Caucasian population (OR = 0.72, 95%CI = [0.55, 0.93], P = .01) but not in the Asian population (P > .05). Furthermore, no association was detected between LMP2 CfoI polymorphism and AS complication (AAU). CONCLUSION: Our combined results revealed that the allelic model of LMP2 CfoI might be a protective factor for AS in the Caucasian population. Nevertheless, future studies on different ethnicities with larger sample sizes are needed to obtain a more convincing result.


Asunto(s)
Cisteína Endopeptidasas/genética , Polimorfismo Genético , Espondilitis Anquilosante/genética , Uveítis Anterior/genética , Adolescente , Adulto , Anciano , Niño , Femenino , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Humanos , Masculino , Persona de Mediana Edad , Tamaño de la Muestra , Adulto Joven
9.
BMC Evol Biol ; 19(1): 188, 2019 10 15.
Artículo en Inglés | MEDLINE | ID: mdl-31615394

RESUMEN

BACKGROUND: Hybridization has been widely practiced in plant and animal breeding as a means to enhance the quality and fitness of the organisms. In domestic equids, this hybrid vigor takes the form of improved physical and physiological characteristics, notably for strength or endurance. Because the offspring of horse and donkey is generally sterile, this widely recognized vigor is expressed in the first generation (F1). However, in the absence of recombination between the two parental genomes, F1 hybrids can be expected to be phenotypically intermediate between their parents which could potentially restrict the possibilities of an increase in overall fitness. In this study, we examine the morphology of the main limb bones of domestic horses, donkeys and their hybrids to investigate the phenotypic impact of hybridization on the locomotor system. We explore bone shape variation and covariation to gain insights into the morphological and functional expressions of the hybrid vigor commonly described in domestic equids. RESULTS: Our data reveal the occurrence of transgressive effects on several bones in the F1 generation. The patterns of morphological integration further demonstrate that the developmental processes producing covariation are not disrupted by hybridization, contrary to functional ones. CONCLUSIONS: These results suggest that an increase in overall fitness could be related to more flexibility in shape change in hybrids, except for the main forelimb long bones of which the morphology is strongly driven by muscle interactions. More broadly, this study illustrates the interest of investigating not only bone shape variation but also underlying processes, in order to contribute to better understanding how developmental and functional mechanisms are affected by hybridization.


Asunto(s)
Animales Domésticos/genética , Huesos/anatomía & histología , Caballos/genética , Vigor Híbrido/genética , Hibridación Genética , Animales , Cruzamiento , Análisis de los Mínimos Cuadrados , Modelos Teóricos , Análisis de Componente Principal , Tamaño de la Muestra
10.
Medicine (Baltimore) ; 98(43): e17630, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31651877

RESUMEN

BACKGROUND: The randomized controlled trial (RCT) is the gold-standard research design in biomedicine. However, practical concerns often limit the sample size, n, the number of patients in a RCT. We aim to show that the power of a RCT can be increased by increasing p, the number of baseline covariates (sex, age, socio-demographic, genomic, and clinical profiles et al, of the patients) collected in the RCT (referred to as the 'dimension'). METHODS: The conventional test for treatment effects is based on testing the 'crude null' that the outcomes of the subjects are of no difference between the two arms of a RCT. We propose a 'high-dimensional test' which is based on testing the 'sharp null' that the experimental intervention has no treatment effect whatsoever, for patients of any covariate profile. RESULTS: Using computer simulations, we show that the high-dimensional test can become very powerful in detecting treatment effects for very large p, but not so for small or moderate p. Using a real dataset, we demonstrate that the P value of the high-dimensional test decreases as the number of baseline covariates increases, though it is still not significant. CONCLUSION: In this big-data era, pushing p of a RCT to the millions, billions, or even trillions may someday become feasible. And the high-dimensional test proposed in this study can become very powerful in detecting treatment effects.


Asunto(s)
Macrodatos , Ensayos Clínicos Controlados Aleatorios como Asunto , Simulación por Computador , Interpretación Estadística de Datos , Humanos , Tamaño de la Muestra
12.
Rev Bras Epidemiol ; 22Suppl 1(Suppl 1): e190002, 2019.
Artículo en Inglés, Portugués | MEDLINE | ID: mdl-31576978

RESUMEN

INTRODUCTION: Respondent-Driven Sampling (RDS) has been used in surveys with key populations at risk of HIV infection, such as female sex workers (FSW). This article describes the application of the RDS method among FSW in 12 Brazilian cities, during a survey carried out in 2016. METHODOLOGY: A biological and behavioral surveillance study carried out in 12 Brazilian cities, with a minimum sample of 350 FSW in each city. Tests were performed for HIV, syphilis, and hepatitis B and C infections. A social-behavioral questionnaire was also applied. RESULTS: The sample was comprised of 4,328 FSW. For data analysis, the sample was weighted according to each participant's network size (due consideration to the implications of RDS complex design and to the effects of homophilia are recommended). DISCUSSION: Although RDS methods for obtaining a statistical sample are based on strong statistical assumptions, allowing for an estimation of statistical parameters, with each new application the method has been rethought. In the analysis of whole-sample data, estimators were robust and compatible with those found in 2009. However, there were significant variations according to each city. CONCLUSION: The achieved sample size was of great relevance for assessing progress and identifying problems regarding the prevention and treatment of Sexually Transmitted Infections. New RDS studies with more time and operational resources should be envisaged. This could further network development.


Asunto(s)
Infecciones por VIH/epidemiología , Encuestas Epidemiológicas/métodos , Hepatitis C/epidemiología , Vigilancia de la Población/métodos , Trabajadores Sexuales/estadística & datos numéricos , Sífilis/epidemiología , Brasil/epidemiología , Ciudades , Femenino , Humanos , Factores de Riesgo , Tamaño de la Muestra , Muestreo , Encuestas y Cuestionarios
13.
Dis Colon Rectum ; 62(12): 1485-1493, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-31567920

RESUMEN

BACKGROUND: Systemic inflammation may influence the response to systemic chemotherapy or the prognosis in patients with various cancers. The Naples prognostic score, based on inflammatory and nutritional statuses, is a useful prognostic marker in patients undergoing surgery for colorectal cancer; however, its significance in patients with metastatic colorectal cancer remains unclear. OBJECTIVE: We aimed to evaluate the prognostic significance of the Naples prognostic factor in patients with metastatic colorectal cancer receiving first-line chemotherapy and to compare its prognostic accuracy with the neutrophil:lymphocyte ratio, platelet:lymphocyte ratio, and the systemic immune-inflammatory index. DESIGN: This was a retrospective study of prospectively collected data. SETTINGS: This study was conducted at a university hospital. PATIENTS: A total of 259 patients received first-line systemic chemotherapy for metastatic colorectal cancer. MAIN OUTCOME MEASURES: The Naples prognostic score was calculated by a composite score of albumin and cholesterol concentrations, lymphocyte:monocyte ratio, and neutrophil:lymphocyte ratio. The patients were divided into 3 groups based on increasing Naples scores (groups 0-2), and the associations of the Naples prognostic score with clinicopathologic features and overall survival were evaluated. RESULTS: Higher Naples prognostic score was positively associated with right-sided primary tumors and synchronous metastases and negatively with primary tumor resection. Patients in group 2 (high Naples prognostic score) had significantly shorter overall survival than those in groups 0 and 1 (p = 0.012 and 0.022). Multivariate Cox regression analysis identified the Naples prognostic score as an independent prognostic factor for overall survival (HR = 1.574; p = 0.004). Time-dependent receiver operating characteristic curve analysis showed that Naples prognostic score was more sensitive than other prognostic factors for predicting overall survival. LIMITATIONS: The main limitations are the sample size, single institutional feature, and treatment heterogeneity. CONCLUSIONS: The Naples prognostic score may be a useful prognostic marker in patients with metastatic colorectal cancer receiving systemic chemotherapy. See Video Abstract at http://links.lww.com/DCR/B72. LA PUNTUACIÓN PRONÓSTICA DE NÁPOLES ES UN MARCADOR PRONÓSTICO ÚTIL EN PACIENTES CON CÁNCER COLORRECTAL METASTÁSICO: La inflamación sistémica puede influir en la respuesta a la quimioterapia sistémica o el pronóstico en pacientes con varios tipos de cáncer. La puntuación pronóstica de Nápoles, basada en estados inflamatorios y nutricionales, es un marcador pronóstico útil en pacientes sometidos a cirugía por cáncer colorrectal; sin embargo, su importancia en pacientes con cáncer colorrectal metastásico sigue siendo incierta.El objetivo fue evaluar la importancia pronóstica del factor pronóstico de Nápoles en pacientes con cáncer colorrectal metastásico que reciben quimioterapia de primera línea y comparar su precisión pronóstica con la relación neutrófilos: linfocitos, plaquetas: linfocitos y el índice sistémico inmune-inflamatorio.Este estudio se realizó en un hospital universitario.Este fue un estudio retrospectivo de datos recolectados prospectivamente.Un total de 259 pacientes recibieron quimioterapia sistémica de primera línea para el cáncer colorrectal metastásico.La puntuación pronóstica de Nápoles se calculó mediante una puntuación compuesta de concentraciones de albúmina y colesterol, proporción de linfocitos: monocitos y proporción de neutrófilos: linfocitos. Los pacientes se dividieron en tres grupos basados en el aumento de las puntuaciones de Nápoles (grupos 0-2, respectivamente) y se evaluaron las asociaciones de la puntuación pronóstica de Nápoles con las características clínico-patológicas y la supervivencia general.La puntuación pronóstica de Nápoles es más alta se asoció positivamente con los tumores primarios del lado derecho y metástasis sincrónicas, y negativamente con la resección del tumor primario. Los pacientes del grupo 2 (alto puntaje pronóstico de Nápoles) tuvieron una supervivencia general significativamente menor que los de los grupos 0 y 1 (p = 0.012 y 0.022, respectivamente). El análisis de regresión de Cox multivariado identificó la puntuación pronóstica de Nápoles como un factor pronóstico independiente para la supervivencia global (índice de riesgo = 1.574; p = 0.004). El análisis de la curva característica de funcionamiento del receptor dependiente del tiempo mostró que la puntuación pronóstica de Nápoles era más sensible que otros factores pronósticos para predecir la supervivencia global.Las principales limitaciones son el tamaño de la muestra, la característica institucional única y la heterogeneidad del tratamiento.La puntuación pronóstica de Nápoles puede ser un marcador pronóstico útil en pacientes con cáncer colorrectal metastásico que reciben quimioterapia sistémica. Vea el Abstract del video en http://links.lww.com/DCR/B72.


Asunto(s)
Biomarcadores de Tumor/inmunología , Neoplasias Colorrectales/tratamiento farmacológico , Estado Nutricional , Adulto , Anciano , Anciano de 80 o más Años , Colesterol/sangre , Neoplasias Colorrectales/sangre , Quimioterapia , Femenino , Humanos , Recuento de Linfocitos , Masculino , Persona de Mediana Edad , Metástasis de la Neoplasia , Recuento de Plaquetas , Pronóstico , Curva ROC , Estudios Retrospectivos , Tamaño de la Muestra , Albúmina Sérica Humana/análisis , Resultado del Tratamiento
14.
Environ Sci Technol ; 53(22): 13284-13292, 2019 Nov 19.
Artículo en Inglés | MEDLINE | ID: mdl-31625379

RESUMEN

The power of remote vehicle emission sensing stems from the big sample size obtained and its related statistical representativeness for the measured emission rates. But how many records are needed for a representative measurement and when does the information gain per record become insignificant? We use Monte Carlo simulations to determine the relationship between the sample size and the accuracy of the sample mean and variance. We take the example of NO emissions from diesel cars measured by remote emission monitors between 2011 and 2018 at various locations in Europe. We find that no more than 200 remote sensing records are sufficient to approximate the mean emission rate for Euro 4, 5, and 6a/b diesel cars with 80% certainty within a ±1 g NO per kg fuel tolerance margin (∼±50 mg NO per km). Between 300 and 800 remote sensing records are needed to approximate also the variance of the mean NO emission rates for those diesel car technologies. This translates to only 2 and up to 9 measurement days to characterize the means and their variance for a car fleet typical in Europe.


Asunto(s)
Contaminantes Atmosféricos , Monitoreo del Ambiente , Europa (Continente) , Vehículos a Motor , Tamaño de la Muestra , Emisiones de Vehículos
17.
Can Assoc Radiol J ; 70(4): 344-353, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31522841

RESUMEN

PURPOSE: The required training sample size for a particular machine learning (ML) model applied to medical imaging data is often unknown. The purpose of this study was to provide a descriptive review of current sample-size determination methodologies in ML applied to medical imaging and to propose recommendations for future work in the field. METHODS: We conducted a systematic literature search of articles using Medline and Embase with keywords including "machine learning," "image," and "sample size." The search included articles published between 1946 and 2018. Data regarding the ML task, sample size, and train-test pipeline were collected. RESULTS: A total of 167 articles were identified, of which 22 were included for qualitative analysis. There were only 4 studies that discussed sample-size determination methodologies, and 18 that tested the effect of sample size on model performance as part of an exploratory analysis. The observed methods could be categorized as pre hoc model-based approaches, which relied on features of the algorithm, or post hoc curve-fitting approaches requiring empirical testing to model and extrapolate algorithm performance as a function of sample size. Between studies, we observed great variability in performance testing procedures used for curve-fitting, model assessment methods, and reporting of confidence in sample sizes. CONCLUSIONS: Our study highlights the scarcity of research in training set size determination methodologies applied to ML in medical imaging, emphasizes the need to standardize current reporting practices, and guides future work in development and streamlining of pre hoc and post hoc sample size approaches.


Asunto(s)
Investigación Biomédica , Diagnóstico por Imagen/estadística & datos numéricos , Aprendizaje Automático , Humanos , Tamaño de la Muestra
18.
Biomed Environ Sci ; 32(8): 614-623, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31488237

RESUMEN

OBJECTIVE: To develop methods for determining a suitable sample size for bioequivalence assessment of generic topical ophthalmic drugs using crossover design with serial sampling schemes. METHODS: The power functions of the Fieller-type confidence interval and the asymptotic confidence interval in crossover designs with serial-sampling data are here derived. Simulation studies were conducted to evaluate the derived power functions. RESULTS: Simulation studies show that two power functions can provide precise power estimates when normality assumptions are satisfied and yield conservative estimates of power in cases when data are log-normally distributed. The intra-correlation showed a positive correlation with the power of the bioequivalence test. When the expected ratio of the AUCs was less than or equal to 1, the power of the Fieller-type confidence interval was larger than the asymptotic confidence interval. If the expected ratio of the AUCs was larger than 1, the asymptotic confidence interval had greater power. Sample size can be calculated through numerical iteration with the derived power functions. CONCLUSION: The Fieller-type power function and the asymptotic power function can be used to determine sample sizes of crossover trials for bioequivalence assessment of topical ophthalmic drugs.


Asunto(s)
Ensayos Clínicos como Asunto/métodos , Soluciones Oftálmicas/farmacocinética , Administración Tópica , Estudios Cruzados , Humanos , Modelos Teóricos , Tamaño de la Muestra , Equivalencia Terapéutica
19.
BMC Res Notes ; 12(1): 557, 2019 Sep 03.
Artículo en Inglés | MEDLINE | ID: mdl-31481129

RESUMEN

BACKGROUND: Excessive and patterned ambulation is associated with falls, urinary tract infections, co-occurring delirium and other acute events among long-term care residents with cognitive impairment/dementia. This study will test a predictive longitudinal data model that may lead to the preservation of function of this vulnerable population. METHODS/DESIGN: This is a single group, longitudinal study with natural observations. Data from a real-time locating system (RTLS) will be used to objectively and continuously measure ambulation activity for up to 2 years. These data will be combined with longitudinal acute event and functional status data to capture patterns of change in health status over time. Theory-driven multilevel models will be used to test the trajectories of falls and other acute conditions as a function of the ambulation activity and demographic, functional status, gait quality and balance ability including potential mediation and/or moderation effects. Data-driven machine learning algorithms will be applied to run screening of the high dimensional RTLS data together with other variables to discover new and robust predictors of acute events. DISCUSSION: The findings from this study will lead to the early identification of older adults at risk for falls and the onset of acute medical conditions and interventions for individualized care.


Asunto(s)
Disfunción Cognitiva/fisiopatología , Demencia/fisiopatología , Cuidados a Largo Plazo , Modelos Teóricos , Proyectos de Investigación , Caminata/fisiología , Adulto , Humanos , Estudios Longitudinales , Tamaño de la Muestra
20.
Biol Pharm Bull ; 42(9): 1600-1604, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31474721

RESUMEN

The purpose of this study was to establish a modified method of three-compartment model analysis that minimized the sampling frequency. A Caco-2 permeability assay was performed on ten structurally diverse compounds with passive diffusion. A three-compartment model was analyzed by a conventional method and a method with fewer sampling points, called the simplified method, using concentration-time profiles in the donor, intracellular, and receiver compartments. The concentration-time profiles in all compartments were well described by the conventional method. The calculated unbound fraction of intracellular (fu2) and apparent permeability coefficient (Papp) were 0.0107-1.22 and 0.886-146 × 10-6 cm/s, respectively. The simplified method also described the concentration profiles in the compartments of all ten compounds except one, ibuprofen. The difference in values calculated by the simplified method compared to the conventional method was between -7 and 7% for fu2 and between -6 and 42% for Papp. These results suggested that the parameter values from the simplified method were comparable with those from the conventional method. The simplified method may be a promising approach to improve the throughput of three-compartment model analyses of Caco-2 permeability assays in the early stages of drug discovery.


Asunto(s)
Modelos Biológicos , Preparaciones Farmacéuticas/metabolismo , Bioensayo , Transporte Biológico , Células CACO-2 , Humanos , Absorción Intestinal/fisiología , Permeabilidad , Tamaño de la Muestra
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