977 resultados para PREDICTOR
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OBJECTIVES We sought to assess the prognostic value and risk classification improvement using contemporary single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) to predict all-cause mortality. BACKGROUND Myocardial perfusion is a strong estimator of prognosis. Evidence published to date has not established the added prognostic value of SPECT-MPI nor defined an approach to detect improve classification of risk in women from a developing nation. METHODS A total of 2,225 women referred for SPECT-MPI were followed by a mean period of 3.7 +/- 1.4 years. SPECT-MPI results were classified as abnormal on the presence of any perfusion defect. Abnormal scans were further classified as with mild/moderate reversible, severe reversible, partial reversible, or fixed perfusion defects. Risk estimates for incident mortality were categorized as <1%/year, 1% to 2%/year, and >2%/year using Cox proportional hazard models. Risk-adjusted models incorporated clinical risk factors, left ventricular ejection fraction (LVEF), and perfusion variables. RESULTS All-cause death occurred in 139 patients. SPECT-MPI significantly risk stratified the population; patients with abnormal scans had significantly higher death rates compared with patients with normal scans, 13.1% versus 4.0%, respectively (p < 0.001). Cox analysis demonstrated that after adjusting for clinical risk factors and LVEF, SPECT-MPI improved the model discrimination (integrated discrimination index = 0.009; p = 0.02), added significant incremental prognostic information (global chi-square increased from 87.7 to 127.1; p < 0.0001), and improved risk prediction (net reclassification improvement = 0.12; p = 0.005). CONCLUSIONS SPECT-MPI added significant incremental prognostic information to clinical and left ventricular functional variables while enhancing the ability to classify this Brazilian female population into low-and high-risk categories of all-cause mortality. (J Am Coll Cardiol Img 2011;4:880-8) (C) 2011 by the American College of Cardiology Foundation
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Introduction: Hyaluronidases (HAases) are enzymes related to cancer progression. Isoforms of HAases have been described as products of alternative splicing responsible for differences in enzyme activity. The heterogeneity of HAase expression has been identified in tumors and could be related to the differences in their biological behavior. Methods: Thirty-seven patients subjected to radical prostatectomy for prostate cancer were divided into 2 groups for the analyses: Low (<= 6-18) and high (>= 7-19) Gleason score and tumor behavior; recurrence 15 and nonrecurrence 22, mean follow-up 52.6 months. Conclusion: A profile of HAase related to low Gleason score and non-tumor recurrence was characterized by expression of HYAL3-v1, HYAL1-v3, and HYAL3-v2. More studies should be made in order to confirm with larger series. (C) 2009 Elsevier Inc. All rights reserved.
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Objective: To verify whether preoperative respiratory muscle strength and ventilometric parameters, among other clinically relevant factors, are associated with the need for prolonged invasive mechanical ventilation (PIMV) due to cardiorespiratory complications following heart valve surgery. Methods: Demographics, preoperative ventilometric and manometric data, and the hospital course of 171 patients, who had undergone heart valve surgery at Hospital das Clinicas da Faculdade de Medicina de Ribeirao Preto, were prospectively collected and subjected to univariate analysis for identifying the risk factors for PIMV. Results: The hospital mortality was 7%. About 6% of the patients, who had undergone heart valve surgery required PIMV because of postoperative cardiorespiratory dysfunction. Their hospital mortality was 60% (vs 4%, p < 0.001). Univariate analysis revealed that preoperative respiratory muscle dysfunction, characterized by maximal inspiratory and expiratory pressure below 70% of the predicted values combined with respiratory rate above 15 rpm during ventilometry, was associated with postoperative PIMV (p = 0.030, odds ratio: 50, 95% confidence interval (CI): 1.2-18). Postoperative PIMV was also associated with: (1) body mass index (BMI) < 18.5 (odds ratio: 7.2, 95% CI: 1.5-32), (2) body weight < 50 kg (odds ratio: 6.5, 95% CI: 1.6-25), (3) valve operation due to acute endocarditis (odds ratio: 5.5, 95% CI: 0.98-30), and (4) concomitant operation for mitral and tricuspid valve dysfunction (p = 0.047, odds ratio: 5.0, 95% CI: 1.1-22). Conclusion: Our results have demonstrated that respiratory muscle dysfunction, among other clinical factors, is associated with the need for PIMV due to cardiovascular or pulmonary dysfunction after heart valve surgery. (C) 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B. V. All rights reserved.
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Purpose: To correlate ovarian reserve (OR) markers with response in assisted reproduction techniques (ART) and determine their ability to predict poor response among patients with endometriosis (EDT). Methods: We evaluated ART cycles of 27 women with EDT and 50 with exclusive male factor. Basal follicle stimulating hormone (FSH) and anti-mullerian hormone (AMH) levels were determined. Ovarian response to gonadotropin stimulation was assessed and correlation coefficients calculated between the variables and reserve markers. Areas under the curve (AUC) determined ability of tests to predict poor response. Results: AMH was significantly correlated with response in both groups and it was the only marker with significant discriminative capacity to predict poor response among EDT (AUC = 0.842; 95% CI: 0.651-0.952) and control group (AUC = 0.869; 95% CI: 0.743-0.947). Conclusion: Infertile patients with endometriosis can benefit from the pre-therapeutic assessment of OR markers. However, regardless of disease presence, only AMH predicts poor response to stimulus.
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Objective: To assess the impact of the mean oocyte diameter (MOD) on occurrence of fertilization and embryo quality in assisted reproduction cycles. Design: Prospective observational study. Setting: Sector of Human Reproduction of the University Hospital, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo (HCFMRP-USP). Patient(s): Thirty-five women undergoing intracytoplasmic sperm injection (ICSI) at the University Hospital of Ribeirao Preto from May to October 2007. Intervention(s): MOD assessment. Main Outcome Measure(s): Occurrence of fertilization and qualitative embryo classification on 2nd and 3rd day after ICSI. Result(s): We divided 160 metaphase II oocytes according to MOD into groups A (MOD below the 25th percentile), B (MOD between 25th and 75th percentile), and C (MOD above the 75th percentile). There was no statistically significant association between MOD and the occurrence of fertilization or the qualitative embryo classification on days 2 and 3. There was no statistically significant difference between groups regarding number of cells or the qualitative embryo classification on days 2 and 3. Conclusion(s): The MOD of mature oocytes does not seem to be related to the occurrence of fertilization or to the developmental quality of human embryos on days 2 and 3 after ICSI. (Fertil Steril(R) 2010;93:621-5. (C)2010 by American Society for Reproductive Medicine.)
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MRI is an important tool for investigating breast cancer. Although recognized as the method of choice for screening highrisk patients, and for other indications the role of MRI for lesion characterization remains controversial. Recently some authors have advocated the use of morphologic and postcontrast features for this purpose. Quantitative breast MRI techniques have not been applied extensively in breast diseases. Magnetization transfer (MT) is a quantitative MR technique commonly used to investigate neurological diseases. In breast diseases the use of MT has been limited to improving visualization of areas of enhancement in postcontrast images. The purpose of this study was to evaluate the feasibility and utility of MT in discriminating benign from malignant breast lesions. Fifty-two lesions, Bl-RADS 4 and 5, from 49 patients, were prospectively evaluated using the MT ratio (MTR). Patients were divided into two groups: benign and malignant lesions. The MTR of fat, pectoralis major muscle, fibroglandular tissue, and breast lesions were calculated. A statistically significant difference was found between MTR from benign and malignant lesions (P < 0.001). Preliminary results suggest that MT can be used to evaluate breast lesions. Further studies are necessary to better define the utility and applicability of this technique.
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The aim of the present study was to determine the relationship among body weight (BW), body condition score (BCS) and rump fat thickness (RFAT) measured by ultrasonography, and validate the relationship between BCS and RFAT over the time. Two hundred sixty and six Nelore cows had their BW, BCS and RFAT evaluated at five different moments during the production cycle: M1) weaning: M2) parturition, M3) 42 days post-partum; M4) 82 days postpartum and M5) 112 days post-partum. A BCS value was attributed for each cow following a I to 5 points scale. Ultrasonographic images for RFAT measurement were obtained using a 3.5 MHz linear transducer. Images were immediately analyzed as soon as they were formed and frozen. Body condition scores and ultrasound measurements were collected on the same day by a single trained technician. The relationship between BCS and RFAT values was investigated by regression models. The analysis of similarity among the five obtained models was performed using the proc MIXED from SAS and the correlations among variables were analyzed with proc CORR from SAS. The BCS was able to predict RFAT in Nelore cows in all different moments evaluated. Also, it was shown that BCS presented high correlation (r=0.82 to 0.93) and relationship (R(2) = 0.73 to 0.92) with RFAT. However, both BCS and RFAT showed low correlation (r=0.37 to 0.50) and relationship (R(2) = 0.13 to 0.25) with BW. The BCS classification by visual method using a 1 to 5 point scale, was able to predict the RFAT in Nelore cows over the time. (C) 2008 Elsevier B.V. All rights reserved.
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In this paper we construct predictor-corrector (PC) methods based on the trivial predictor and stochastic implicit Runge-Kutta (RK) correctors for solving stochastic differential equations. Using the colored rooted tree theory and stochastic B-series, the order condition theorem is derived for constructing stochastic RK methods based on PC implementations. We also present detailed order conditions of the PC methods using stochastic implicit RK correctors with strong global order 1.0 and 1.5. A two-stage implicit RK method with strong global order 1.0 and a four-stage implicit RK method with strong global order 1.5 used as the correctors are constructed in this paper. The mean-square stability properties and numerical results of the PC methods based on these two implicit RK correctors are reported.
Perceived stress as a predictor of the self-reported new diagnosis of symptomatic CHD in older women
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This article describes one aspect of a prospective cohort study of 10,432 women aged between 70 and 75 years. After a 3-year period, 503 women self-reported a new diagnosis by a doctor of angina or myocardial infarction (symptomatic coronary heart disease [CHD]). Time one psychosocial variables (Duke Social Support Index, time pressure, Perceived Stress Scale, Mental Health Index, having a partner, educational attainment, and location of residence) were analyzed using univariate binary logistic regression for their ability to predict subsequent symptomatic CHD. Of these variables, the Duke Social Support Index, Perceived Stress Scale and the Mental Health Index were found to be significant predictors of symptomatic CHID diagnosis. Only the Perceived Stress Scale, however, proved to be a significant independent predictor. After controlling for time one nonpsychosocial variables, as well as the frequency of family doctor visits, perceived stress remained a significant predictor of the new diagnosis of symptomatic CHD in this cohort of older women over a 3-year period.
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OBJETIVO: El estrato socioeconómico juega un rol importante en las desigualdades en salud. En México, la prevalencia más alta de casos de SIDA se encuentra en población de estratos más bajos. El propósito de lo estudio fue describir el estrato socioeconómico (ajustado por variables psicosociales, situacionales y demográficas) como un factor predictor del uso consistente del condón, en adolescentes. MÉTODOS: Se incluyó en el estudio una muestra de una encuesta previa aplicada a 1.410 adolescentes de 15 a 19 años y estratificada por edad, género y estrato socioeconómico de Guadalajara, México. El análisis fue aplicado sobre los 251 adolescentes que reportaron actividad sexual. El análisis estadístico se realizó mediante Ji Cuadrada, t-test, ANOVA y regresión logística. RESULTADOS: La frecuencia de uso consistente de condón fue 30,7% y hubo una prevalencia de uso irregular. El estrato socioeconómico alto fue el principal predictor (OR= 11,1, CI95%= 2,6-47,6). Otros predictores significativos fueron el género masculino, el soporte de los pares y el nivel alto de conocimientos sobre VIH/SIDA. CONCLUSIÓN: El estrato socioeconómico es un importante factor predictor del uso consistente del condón.
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The advantageous use of fractional calculus (FC) in the modeling and control of many dynamical systems has been recognized. In this paper, we study the control of a heat diffusion system based on the application of the FC concepts. Several algorithms are investigated and compared, when integrated within a Smith predictor control structure. Simulations are presented assessing the performance of the proposed fractional algorithms.
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The objectives of this study were to compare how different frailty measures (Frailty Phenotype/FP, Groningen Frailty Indicator/GFI and Tilburg Frailty Indicator/TFI) predict short-term adverse outcomes. Secondarily, adopting a multidimensional approach to frailty (integral conceptual model–TFI), this study aims to compare how physical, psychological and social frailty predict the outcomes. A longitudinal study was carried out with 95 community-dwelling elderly. Participants were assessed at baseline for frailty, determinants of frailty, and adverse outcomes (healthcare utilization, quality of life, disability in basic and instrumental activities of daily living/ADL and IADL). Ten months later the outcomes were assessed again. Frailty was associated with specific healthcare utilization indicators: the FP with a greater utilization of informal care; GFI with an increased contact with healthcare professionals; and TFI with a higher amount of contacts with a general practitioner. After controlling for the effect of life-course determinants, comorbidity and adverse outcome at baseline, GFI predicted IADL disability and TFI predicted quality of life. The effect of the FP on the outcomes was not significant, when compared with the other measures. However, when comparing TFI’s domains, the physical domain was the most significant predictor of the outcomes, even explaining part of the variance of ADL disability. Frailty at baseline was associated with adverse outcomes at follow-up. However, the relationship of each frailty measure (FP, GFI and TFI) with the outcomes was different. In spite of the role of psychological frailty, TFI’s physical domain was the determinant factor for predicting disability and most of the quality of life.
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Background: Upper arm anthropometry has been used in the nutritional assessment of small infants, but it has not yet been validated as a predictor of regional body composition in this population. Objective: Validation of measured and derived upper arm anthropometry as a predictor of arm fat and fat-free compartments in preterm infants. Methods: Upper arm anthropometry, including the upper arm cross-sectional areas, was compared individually or in combination with other anthropometric measurements, with the cross-sectional arm areas measured by magnetic resonance imaging, in a cohort of consecutive preterm appropriate-for-gestationalage neonates, just before discharge. Results: Thirty infants born with (mean 8 SD) a gestational age of 30.7 8 1.9 weeks and birth weight of 1,380 8 325 g, were assessed at 35.4 8 1.1 weeks of corrected gestational age, weighing 1,785 8 93 g. None of the anthropometric measurements are reliable predictors (r 2 ! 0.56) of the measurements obtained by magnetic resonance imaging, individually or in combination with other anthropometric measurements. Conclusion: Both measured anthropometry and derived upper arm anthropometry are inaccurate predictors of regional body composition in preterm appropriate-for-gestational-age infants.
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The recent developments on Hidden Markov Models (HMM) based speech synthesis showed that this is a promising technology fully capable of competing with other established techniques. However some issues still lack a solution. Several authors report an over-smoothing phenomenon on both time and frequencies which decreases naturalness and sometimes intelligibility. In this work we present a new vowel intelligibility enhancement algorithm that uses a discrete Kalman filter (DKF) for tracking frame based parameters. The inter-frame correlations are modelled by an autoregressive structure which provides an underlying time frame dependency and can improve time-frequency resolution. The system’s performance has been evaluated using objective and subjective tests and the proposed methodology has led to improved results.