Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 15 de 15
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
BMC Cancer ; 24(1): 513, 2024 Apr 23.
Artículo en Inglés | MEDLINE | ID: mdl-38654241

RESUMEN

BACKGROUND: [18F]FDG-PET/CT is used for staging and treatment planning in patients with locally advanced cervical cancer (LACC). We studied if a PET-based prediction model could provide additional risk stratification beyond International Federation of Gynaecology and Obstetrics (FIGO) staging in our population with LACC to aid treatment decision making. METHODS: In total, 183 patients with LACC treated with chemoradiation between 2013 and 2018 were included. Patients were treated according to FIGO 2009 and retrospectively reclassified according to FIGO 2018 staging system. After validation of an existing PET-based prediction model, the predicted recurrent free survival (RFS), disease specific survival (DSS) and overall survival (OS) at 1, 3, and 5 years, based on metabolic tumor volume (MTV), maximum standardized uptake value (SUVmax) and highest level of [18F]FDG-positive node was calculated. Then the observed survival was compared to the predicted survival. An area under the curve (AUC) close to or higher than 0.7 was considered adequate for accurate prediction. The Youden (J) index defined survival chance cutoff values for low and high risk groups. RESULTS: All AUC values for the comparison between predicted and observed outcomes were > 0.7 except for 5-year RFS and for 5-year OS which were close to 0.7 (0.684 and 0.650 respectively). Cutoff values for low and high risk survival chance were 0.44 for the 3-year RFS and 0.47 for the 5-year OS. The FIGO 2009 system could not differentiate between the risk profiles. After reclassification according to FIGO 2018, all patients with stage IIIC2 and IVB fell in the high risk and almost all patients with stages IB2-IIIB and IVA in the low risk group. In patients with stage IIIC1 disease the FIGO stage cannot discriminate between the risk profiles. CONCLUSIONS: Low and high risk patients with LACC can be identified with the PET-based prediction model. In particular patients with stage IIIC1 need additional risk stratification besides the FIGO 2018 staging. The Kidd model could be a useful tool to aid treatment decision making in these patients. Our results also support the choice of [18F]FDG-PET/CT imaging in patients with LACC.


Asunto(s)
Fluorodesoxiglucosa F18 , Estadificación de Neoplasias , Tomografía Computarizada por Tomografía de Emisión de Positrones , Neoplasias del Cuello Uterino , Humanos , Femenino , Neoplasias del Cuello Uterino/diagnóstico por imagen , Neoplasias del Cuello Uterino/patología , Neoplasias del Cuello Uterino/mortalidad , Neoplasias del Cuello Uterino/terapia , Tomografía Computarizada por Tomografía de Emisión de Positrones/métodos , Persona de Mediana Edad , Estudios Retrospectivos , Adulto , Anciano , Medición de Riesgo/métodos , Quimioradioterapia , Radiofármacos , Anciano de 80 o más Años , Pronóstico
2.
Am J Orthod Dentofacial Orthop ; 142(6): 780-91, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23195364

RESUMEN

INTRODUCTION: Orthodontists have used various compliance-dependent physical means such as headgears and intraoral appliances to prevent anchorage loss. The aim of this study was to determine whether 1 local application of the bisphosphonate zoledronate could be used to prevent anchorage loss during extraction space closure in rats. METHODS: Thirty rats had their maxillary left first molars extracted and their maxillary left second molars protracted into the extraction space with a 10-g nickel-titanium closing coil for 21 days. Fifteen control rats received a local injection of phosphate-buffered saline solution, and 15 experimental rats received 16 µg of the bisphosphonate zoledronate. Bisphosphonate was also delivered directly into the extraction site and left undisturbed for 5 minutes. Cephalograms and incremental thickness gauges were used to measure tooth movements. Tissues were analyzed by microcomputed tomography and histology. RESULTS: The control group demonstrated significant (P <0.05) tooth movements throughout the 21-day period. They showed significantly greater tooth movements than the experimental group beginning in the second week. The experimental group showed no significant tooth movement after the first week. The microcomputed tomography and histologic observations showed significant bone loss in the extraction sites and around the second molars of the controls. In contrast, the experimental group had bone preservation and bone fill. There was no evidence of bisphosphonate-associated osteonecrosis in any sample. CONCLUSIONS: A single small, locally applied dose of zoledronate provided maximum anchorage and prevented significant bone loss.


Asunto(s)
Pérdida de Hueso Alveolar/prevención & control , Conservadores de la Densidad Ósea/uso terapéutico , Difosfonatos/uso terapéutico , Imidazoles/uso terapéutico , Métodos de Anclaje en Ortodoncia/instrumentación , Cierre del Espacio Ortodóncico/instrumentación , Administración Tópica , Animales , Conservadores de la Densidad Ósea/administración & dosificación , Difosfonatos/administración & dosificación , Imidazoles/administración & dosificación , Ratas , Ácido Zoledrónico
3.
Artículo en Inglés | MEDLINE | ID: mdl-31119130

RESUMEN

Osteoblast-derived extracellular vesicles (EV) are a collection of secreted (sEVs) and matrix-bound nanoparticles that function as foci for mineral nucleation and accumulation. Due to the fact sEVs can be isolated directly from the culture medium of mineralizing osteoblasts, there is growing interest their application regenerative medicine. However, at present therapeutic advancements are hindered by a lack of understanding of their precise temporal contribution to matrix mineralization. This study advances current knowledge by temporally aligning sEV profile and protein content with mineralization status. sEVs were isolated from mineralizing primary osteoblasts over a period of 1, 2, and 3 weeks. Bimodal particle distributions were observed (weeks 1 and 3: 44 and 164 nm; week 2: 59 and 220 nm), indicating a heterogeneous population with dimensions characteristic of exosome- (44 and 59 nm) and microvesicle-like (164 and 220 nm) particles. Proteomic characterization by liquid chromatography tandem-mass spectrometry (LC-MS/MS) revealed a declining correlation in EV-localized proteins as mineralization advanced, with Pearson correlation-coefficients of 0.79 (week 1 vs. 2), 0.6 (2 vs. 3) and 0.46 (1 vs. 3), respectively. Principal component analysis (PCA) further highlighted a time-dependent divergence in protein content as mineralization advanced. The most significant variations were observed at week 3, with a significant (p < 0.05) decline in particle concentration, visual evidence of EV rupture and enhanced mineralization. A total of 116 vesicle-localized proteins were significantly upregulated at week 3 (56% non-specifically, 19% relative to week 1, 25% relative to week 2). Gene ontology enrichment analysis of these proteins highlighted overrepresentation of genes associated with matrix organization. Of note, increased presence of phospholipid-binding and calcium channeling annexin proteins (A2, A5, and A6) indicative of progressive variations in the nucleational capacity of vesicles, as well as interaction with the surrounding ECM. We demonstrate sEV-mediated mineralization is dynamic process with variations in vesicle morphology and protein content having a potential influence on developmental changes matrix organization. These findings have implications for the selection and application of EVs for regenerative applications.

5.
Eur J Gastroenterol Hepatol ; 12(7): 787-94, 2000 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10929907

RESUMEN

BACKGROUND AND AIMS: Impaired gallbladder motor functions are important in the pathogenesis of primary cholesterol gallstones, and possibly in the pathogenesis of recurrent gallstones. By using ultrasonography and cholescintigraphy simultaneously, we recently defined new parameters of gallbladder motor function (postprandial refilling and turnover in addition to emptying), which were markedly impaired in gallstone patients. The aim of this study was to assess the value of these new parameters in distinguishing patients with from those without gallstone recurrence. METHODS: We studied 11 patients with gallstone recurrence, 11 without gallstone recurrence (at least 40 months after complete dissolution by oral bile acids) and 11 healthy controls. Simultaneous measurements of gallbladder volume (ultrasound) and gallbladder counts (gamma-camera scintigraphy) were carried out in the fasting state and at 10 min intervals following meal ingestion, for a period of 90 min. Gallbladder refilling, turnover of bile and turnover index were calculated, as well as gallbladder emptying by both cholescintigraphy and ultrasound. RESULTS: Patients with gallstone recurrence had reductions in gallbladder emptying, postprandial refilling and gallbladder bile turnover. They also had a significant reduction in the turnover index (1.7 +/- 1.4) compared to controls (3.5 +/- 0.3, P < 0.01) and to patients without gallstone recurrence (3.1 +/- 1.5, P < 0.05). Patients without gallstone recurrence had only a small reduction in emptying and no reduction in postprandial refilling or turnover compared to controls. CONCLUSIONS: We conclude that impairment of gallbladder emptying persists in all patients after gallstone dissolution, albeit to a more pronounced extent in patients with recurrence; but that impairment of postprandial refilling and turnover are specific defects in patients with recurrence.


Asunto(s)
Colelitiasis/complicaciones , Enfermedades de la Vesícula Biliar/etiología , Vaciamiento Vesicular , Periodo Posprandial , Adulto , Anciano , Bilis/metabolismo , Colelitiasis/diagnóstico por imagen , Femenino , Enfermedades de la Vesícula Biliar/diagnóstico , Enfermedades de la Vesícula Biliar/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Probabilidad , Cintigrafía , Recurrencia , Valores de Referencia , Sensibilidad y Especificidad , Estadísticas no Paramétricas , Ultrasonografía
6.
Math Biosci ; 97(1): 121-36, 1989 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-2520203

RESUMEN

Two mathematical models for the control of the growth of a tumor by diffusion of mitotic inhibitor are presented. The inhibitor production rate is taken to be uniform in a necrotic core for the first model and in the nonnecrotic region for the second model. Regions of stable and unstable growth are determined, and conclusions are drawn about the limiting peripheral widths of stable tissue growth for both models. Comparisons of the results from the two models indicate that the models are sensitive to the source distributions of inhibitor production.


Asunto(s)
Neoplasias/patología , Difusión , Inhibidores de Crecimiento/metabolismo , Matemática , Modelos Biológicos , Necrosis , Neoplasias/metabolismo
9.
Ann R Coll Surg Engl ; 90(3): 198-207, 2008 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-18430333

RESUMEN

INTRODUCTION: Patient decision aids could facilitate shared decision-making in joint replacement surgery. However, patient decision aids are not routinely used in this setting. METHODS: With a view to developing a patient decision aid for UK hip/knee joint replacement practice, we undertook a systematic search of the literature for evidence on the use of shared decision-making and patient decision aids in orthopaedics, and a national survey of consultant orthopaedic surgeons on the potential acceptability and feasibility of patient decision aids. RESULTS: We found little published evidence regarding shared decision-making or patient decision aids in orthopaedics. In the survey, 362 of 639 (57%) randomly selected consultant orthopaedic surgeons responded. Respondents appear representative of consultant orthopaedic surgeons in the UK. Of 272 valid responses, 79% (95% CI, 73-85%) thought patient decision aids a good or excellent idea. There was consensus on the potential helpfulness of patient decision aids and core content. A booklet to take home was the preferred medium/practice model. CONCLUSIONS: Despite the increased emphasis on patient involvement in decision-making, there is little evidence in the medical literature relating to shared decision-making or the use of patient decision aids in orthopaedic surgery. Further research in this area of clinical practice is required. Our survey shows that consultant orthopaedic surgeons in the UK are generally positive about the use of patient decision aids for joint replacement surgery. Survey results could inform future development of patient decision aids for joint replacement practice in the UK.


Asunto(s)
Artroplastia de Reemplazo , Toma de Decisiones , Técnicas de Apoyo para la Decisión , Ortopedia , Participación del Paciente , Actitud del Personal de Salud , Estudios Transversales , Estudios de Factibilidad , Encuestas de Atención de la Salud , Humanos , Satisfacción del Paciente , Pautas de la Práctica en Medicina
10.
Invasion Metastasis ; 16(4-5): 247-67, 1996.
Artículo en Inglés | MEDLINE | ID: mdl-9311389

RESUMEN

A brief survey is provided of deterministic models of tumor growth and development over the last three decades. The evolution of these models has proceeded from basic phenomenological and empirical descriptions, through both time-dependent and time-independent diffusion models (largely within the diffusive equilibrium approximation). This includes a study of the diffusion of growth inhibitors. The stability of spheroid models to small perturbations is discussed, and also recent applications of nonlinear elasticity theory and differential geometry to possible staging and grading of cancers. Finally, an excursion is made into catastrophe theory, wherein it is suggested that the cusp catastrophe (in particular) may provide a qualitative description of rapid, almost spontaneous (i) growth of metastases, or (ii) tumor remission (both occurring under certain restrictive conditions).


Asunto(s)
Modelos Biológicos , Neoplasias/patología , Animales , Humanos , Cómputos Matemáticos , Metástasis de la Neoplasia , Regresión Neoplásica Espontánea , Esferoides Celulares
11.
J Math Biol ; 31(7): 735-45, 1993.
Artículo en Inglés | MEDLINE | ID: mdl-8245732

RESUMEN

Properties of the solutions of a nonlinear time-independent diffusion equation are studied. The equation arises in a model of a spherically symmetric vascularized carcinoma with a central necrotic core. The boundary value problem as posed possesses a constant solution when the nutrient consumption rate and deposition rate (from the vascular network) are equal. This solution can lose uniqueness at a critical tumor dimension which corresponds to the onset of instability with respect to deviations from that uniform equilibrium state.


Asunto(s)
Matemática , Modelos Biológicos , Neoplasias/irrigación sanguínea , Neoplasias/patología , División Celular , Humanos , Necrosis
12.
Bull Math Biol ; 52(4): 549-82, 1990.
Artículo en Inglés | MEDLINE | ID: mdl-2397329

RESUMEN

Recently a mathematical model of the prevascular phases of tumor growth by diffusion has been investigated (S.A. Maggelakis and J.A. Adam, Math. Comput. Modeling, in press). In this paper we examine in detail the results and implications of that mathematical model, particularly in the light of recent experimental work carried out on multicellular spheroids. The overall growth characteristics are determined in the present model by four parameters: Q, gamma, b, and delta, which depend on information about inhibitor production rates, oxygen consumption rates, volume loss and cell proliferation rates, and measures of the degree of non-uniformity of the various diffusion processes that take place. The integro-differential growth equation is solved for the outer spheroid radius R0(t) and three related inner radii subject to the solution of the governing time-independent diffusion equations (under conditions of diffusive equilibrium) and the appropriate boundary conditions. Hopefully, future experimental work will enable reasonable bounds to be placed on parameter values referred to in this model: meanwhile, specific experimentally-provided initial data can be used to predict subsequent growth characteristics of in vitro multicellular spheroids. This will be one objective of future studies.


Asunto(s)
Neoplasias Experimentales/patología , Animales , División Celular , Difusión , Inhibidores de Crecimiento/metabolismo , Matemática , Modelos Biológicos , Necrosis , Neoplasias Experimentales/irrigación sanguínea , Neoplasias Experimentales/metabolismo , Consumo de Oxígeno
13.
Gastroenterology ; 109(2): 582-91, 1995 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-7615209

RESUMEN

BACKGROUND & AIMS: Impaired gallbladder emptying is implicated in gallstone disease. Ultrasonography and scintigraphy have shown conflicting results because the former is influenced by postprandial refilling, whereas the latter is not influenced by refilling. The aim of this study was to measure postprandial refilling and turnover of bile by combining the two techniques. METHODS: Simultaneous scintigraphy and ultrasonography were used in 14 patients with gallstones and 11 healthy controls. Measurements were performed while the patients were fasting and at 10-minute intervals after a standard meal for 90 minutes, and the measurements were used to calculate postprandial refilling, turnover of bile (in milliliters), and turnover index. RESULTS: Ultrasonography and scintigraphy provided different gallbladder emptying patterns. Compared with controls, patients with gallstones had impaired emptying by both scintigraphy (P < 0.0001) and ultrasonography (P < 0.01). Postprandial refilling and turnover were both reduced between 60 and 90 minutes (P < 0.05), and the turnover index was markedly reduced (1.8 vs. 3.5; P < 0.001). CONCLUSIONS: Simultaneous scintigraphy and ultrasonography provide a new model of gallbladder motor function showing that refilling begins immediately postprandially. In healthy controls, the gallbladder postprandially handles up to six times its basal volume within a period of 90 minutes, but this turnover of bile is markedly reduced in cholelithiasis causing a reduced washout effect of the gallbladder contents, including cholesterol crystals.


Asunto(s)
Bilis/metabolismo , Colelitiasis/fisiopatología , Alimentos , Vesícula Biliar/fisiología , Análisis de Varianza , Colelitiasis/metabolismo , Ayuno , Femenino , Vesícula Biliar/diagnóstico por imagen , Vesícula Biliar/fisiopatología , Vesícula Biliar/ultraestructura , Humanos , Cintigrafía , Valores de Referencia
14.
Int J Obes Relat Metab Disord ; 26(2): 274-6, 2002 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-11850761

RESUMEN

Orexin-A and -B stimulate appetite and food intake in rats. Orexins and orexin receptors are present in the hypothalamus as well as the enteric nervous system, the pancreas and the gut. The presence of orexins in peripheral blood, however, has not yet been reported. To determine whether orexin-A is present in human plasma and is related to body weight, we measured plasma orexin-A and leptin levels in a population with a body mass index (BMI) range from 19.8 to 59 kg/m(2). Plasma orexin-A levels correlated negatively and plasma leptin levels correlated positively with BMI. In obese and morbidly obese individuals, orexin-A levels were significantly lower and leptin levels were significantly higher when compared to normal. Our results support previous data suggesting that orexin-A acts also in a peripheral manner. The fact that lower levels of plasma orexin-A are present in obese individuals suggests that it is involved in the regulation of human energy metabolism.


Asunto(s)
Proteínas Portadoras/sangre , Péptidos y Proteínas de Señalización Intracelular , Neuropéptidos/sangre , Obesidad/metabolismo , Índice de Masa Corporal , Estudios de Casos y Controles , Humanos , Leptina/sangre , Obesidad/sangre , Orexinas
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA